Manufactured by the National Piano Manufacturing Company
A rare National Piano Mfg. Co,
token that could be dropped
into a nickel coin slot and was
"Good For 1 Piece of Music."
The National Automatic Music Company coin pianos are well known for the large characteristic “Music Changed Weekly” sign centered on the inside of the upper clear glass window, and for the eight-slot coin mechanism, and also the intricate looking mechanisms scattered over the “keybed” area that would normally be home to a piano keyboard. Intriguing as these captivating upright looking pianos are, it is often the case that an owner of a National automatic piano knows little, if anything, about the company behind these unconventional but musically appealing instruments.
The National Automatic Music Company was founded in Chicago, Illinois, in May of 1909. The founding officers were:
One month later, in June of 1909, the National Piano Manufacturing Company was founded. Its founding officers were:
The two companies were to be closely allied, with the National Automatic Music Company contracting for all output and being the sole distributor for the National Piano Manufacturing Company, the latter being the manufacturer of what is commonly known today as simply the National automatic piano. According to the Labor Statistics from the 1912 Michigan Department of labor, the National Piano Manufacturing Company had a total of 30 employees, there being 27 male employees and 3 female employees of record.
The coin piano being manufactured had the overall shape of a standard upright piano but with no keyboard. Where a keyboard would have normally been located was instead a sprawling and intricate system of shafts, chain sprockets, gears, cams, and other complicated looking contrivances, all of which served to control an elaborate 8-roll revolver magazine (roll changer). It held eight single-tune music rolls and played them as selected by a patron who could drop a nickel into one of eight different coin slots, the vertical slots arranged in a horizontal row located immediately above a numbered music program.
The tracker bar was mounted on a movable framework above the revolver magazine and is lowered onto the roll to be played once it had been moved into the correct playing position. Each of the eight single-tune rolls has its own feed and takeup spools mounted within the revolver side plates. As a roll was played, a feed spool drive follower worked its way along the length of a threaded shaft that was geared to the feed spool’s main shaft, while simultaneously a coiled rewind torsion type spring was gradually wound ever tighter. Then when the music roll was finished playing the tracker bar and the takeup spool drive gear were quickly lifted up and away from the revolver magazine. Now the revolver magazine was free to rotate in preparation for playing whatever the next selection might be. And once the tracker bar and the takeup spool drive gear were lifted away the recently played music the roll was free to rewind, and did so independently of all other mechanisms, it being powered by the coiled rewind torsion spring that had been wound up while the music roll was being played. As the roll rewound, the spool follower traveled back to the start position until it came to rest against a stiff coiled compression type spring, which buffered an abrupt stop, while leaving several turns of paper still on the takeup spool. To eliminate the stress that might otherwise tear the roll at the end of the rewind cycle, the takeup spool had a friction pad that rubbed against a hub at one end of the takeup spool, which provided enough resistance to keep the rewinding paper slightly taught. This friction brake plus the controlled deceleration of the feed spool (when the threaded follower came up against the compression spring stop) were sufficient to keep the music rolls from looping at the end of the rewind cycle and in good playing order.
National pianos were very widely distributed, with the West Coast being a particularly lucrative region. Some of the piano routes were large while others were relatively small, but nevertheless all were owned by the National Automatic Music Company. To keep track of the profitability of any particular piano route the company maintained local bank accounts in various cities, so that each route manager could make a direct deposit of the money collected. If there were expenses incurred by the route operator they were paid out of the same local account. A certain percentage of the receipts were used to keep the route pianos in good working order. This methodology allowed the head office in Grand Rapids, Michigan, to easily keep track of the viability of each route, and were best to focus their marketing expertise.
The business prospered and by the summer of 1918 the company announced that it would be moving to a new factory, one of sufficient size to accommodate its expanded coin piano manufacturing and distribution business. Then in 1922 there was another move, also in Grand Rapids, Michigan, when both of the associated National companies moved to 1500 Union Avenue, a factory building earlier occupied by businesses owned by Walter Ioor.
In 1924, the Multi-Reproducer, a derivative revolver magazine product for home use was marketed. It consisted of a furniture cabinet that contained a roll changing mechanism that held eight Welte (Licensee) reproducing piano rolls and that could be located at any distance from a piano, being electrically connected to the piano. The desired music roll could be selected by means of eight buttons in the console, or by a remote control key pad, which had a series of eight labeled buttons. The Multi-Reproducer was marketed by Bush & Lane. Another version of this device was made specifically for pipe organs. Known as the Welte Multi-Control player, it held ten rolls, with certain examples reported that held twelve. (The latter number was reported in original press releases and needs to be confirmed.)
By 1925 the company reportedly had some 4,200 pianos on location, spread over 180 routes in 32 different states. This geographically widespread operation involved about 300 people in the field as route operators and supervisors. To keep the popularity of the pianos alive, the company paid close attention to producing exceedingly well-arranged music rolls featuring the latest popular tunes in addition to old standards and favorites. From roughly 1922 to 1930 it is calculated that about 3,200 new roll titles were issued, which provided a superb library of music.
During the earlier years the National operation had been divided into two separate corporations so as to facilitate administration, with one corporation doing the manufacturing, while the other owned and operated the pianos on route locations. On November 9, 1925, Walter Ioor, then in charge of the whole operation, merged both National companies to form the Automatic Musical Instrument Company (AMI), also based in Grand Rapids, and using the already existing factory. By this time it was becoming readily apparent to management that with the advent of the rapidly evolving electronic age the older electric piano technology would probably sooner rather than later be obsolete, it giving way to the new automatic, electrically-amplified disc phonograph. Although with a new corporate structure the transition to the automatic phonograph had officially begun, the National name continued to be used for a brief time in printed notices. That soon changed and an Automatic Musical Instrument Company decal was prominently displayed on the front of each new or refurbished coin piano. Then the National Automatic Selective Phonograph was introduced in 1927, which was a novel innovation at the time. The new automatic phonograph stored 10 records, and due to the ingenuity of the mechanism either record side could be selected and automatically played. The music was electronically amplified.
The introduction of the automatic phonograph was a fortuitous turning point for the company, and soon thereafter the manufacturing of new National coin pianos ceased. However, many serviceable National pianos were sent back to the factory in Grand Rapids, where the piano actions were refurbished and the mechanisms cleaned and repaired as necessary. Some of these refurbished pianos also had a dog-racing device (called an “automatic whippet race”) retrofitted, or even fewer yet had a “Dancing Figure” (a patented jointed figure that danced to and fro) retrofitted, either of which were visible through the upper clear glass front. But if the stack was beyond reasonable repair, it has been rumored, it was replaced with a new single-tier Pratt-Reed Unitype pneumatic stack (also used in a few 1928 Seeburg Greyhound models), but no Unitype stack has yet to be factually observed in any National piano. Many of the refurbished instruments were also reportedly given a coat of exterior paint, whereupon the renovated pianos were then shipped out for further use on location.
The demand for National automatic pianos, as well as for all other types of coin-operated pianos, diminished in the late 1920s. This is a time when the radio and amplified music on phonographs was in its ascendancy, and due to their popularity were increasingly made available in public venues. By 1930 most of the company's coin-operated pianos had been replaced by automatic phonographs, with about 12,000 then in use. And so the birth of a new industry, one founded on electronics and that could supply a wide variety of music more readily and with greater orchestral fidelity (and without the technical limitations imposed by the cumbersome logistics of arranging and cutting music rolls) took the public interest by storm. The National pianos in places distant from Grand Rapids were simply abandoned, and sold for storage charges, or junked. Some instruments in and near Michigan were kept in operation into the early 1930s.
The Automatic Musical Instrument Company was forced into receivership in 1931. About this time Walter Ioor left the company and moved to Florida. Cornelius H. Knoll, who had been with the National companies since 1920, and was now secretary and treasurer, tended to finances. He took on the task of traveling to some 70 towns and cities in 100 days to check on pianos in storage or that had otherwise been removed from use. This included 400 pianos warehoused in New York City and another 100 located in Philadelphia. The storage charges for useless coin pianos were draining company finances. Knoll made deals, often resulting in turning over the pianos in exchange for the amount due, after which the motors could be removed and sold and the pianos burned, so as to salvage the scrap iron. Most accounts were cleared, and Knoll was able to successfully guide AMI through the Depression years, as well as manage the expansion of the company’s popular line of coin-operated phonographs introduced in 1927. The result of Knoll’s steerage propelled AMI on to great success in later years as a maker of excellent coin-operated phonographs and other devices. The company survives to this day (after various corporate transitions) as AMI Entertainment Network.
|National Tracker Bar Scale|
|Note 1: This is the tracker scale as published by Art Reblitz.
Note 2: Accent or Sforzando expression (tracker bar hole #1) is not used when a balance-beam expression control has been installed.
Note 3: The highest piano note (tracker bar hole #68; C#) is often left disconnected. This is apparently because this hole in certain late rolls was used to operate the "dancing figure" retrofit, rather than the piano note.
The 65-note (A to C#) music rolls made for the National automatic piano are always single tune, 12" wide, and cut with a 6 per inch hole spacing. Several thousand roll titles were issued over the many years the National pianos were produced, and for a few years afterward. The musical arrangements tend to be exceptionally good. Unfortunately, however, it was factory practice to have rolls returned to Grand Rapids, where the paper would be removed from the spools and destroyed, after which the spools would be wound with the latest popular tune. Accordingly, original National rolls are scarce. The decision to take back used rolls probably did help keep fresh music on the pianos, but at the expense of future collectors who would much later come to appreciate the wonderful library of piano arrangements that would, for the most part, be forever lost.
The trade journals of the day consistently mentioned that two associated National companies continued to steadily grow since their inception. That said, however, according to the late Durrell Armstrong: It was about 1920 when the National Automatic Music Company business really took off. From the single tune master rolls a few arrangements were punched out on the 9 per inch scale, with standard 11¼” wide paper and boxed under the brand name of “8-T-8 Harmony” for sales directed to the home player piano market. It is likely that the failure of this venture was due to the player piano rolls not being competitively priced compared to the other more established roll manufacturers. Perhaps a few Grand Rapids, Michigan, merchants did stock the “8-T-8” brand, but whatever the case, the only known copies belong to Mr. Bill Burkhardt, a collector in Grand Rapids, Michigan. The “8-T-8” brand piano rolls were only produced for a short period of time, from 1920 to 1922. An employee who operated the roll perforating department, during this same era, recalled making some ten-tune coin piano rolls using the National master rolls. Although he did not recall who the customer was, he did remember sending out an order about once a month. Except for these few exceptions, all roll arrangements were only issued for consumption on the National automatic piano routes, and by 1925 there were reportedly 4,200 pianos out on 180 routes in 32 states.
It is estimated that about 3,000 musical arrangements were churned out between 1922 and 1930. This would average 7 new music rolls per week, which would almost certainly allow the pianos to live up to the company's motto boldly lettered across the clear glass front, which proclaimed: “Music Changed Weekly.” The down side of this up-to-date music policy was that the music rolls were systematically destroyed as they were replaced, perhaps a good business decision, but a tragedy from the point of view of today’s mechanical music enthusiasts. When route operators put new music on the pianos they naturally removed the older rolls and then periodically shipped them back to the factory in Grand Rapids. There the metal spools were stripped of their paper and a new music roll was wound in its place. Sad in a way, because relatively few of the thousands of arrangements have survived, and in some cases only a single copy exists, while most are gone forever.
A great variety of popular music was cut, along with a smattering of classical and ethnic music. Factory records have been lost as to who supplied the blues arrangements, which are in a style not recognized as being among the great jazz artists of the day, such as “Fats” Waller, J.P. Johnson, Eubie Blake, Lem Fowler, or Jelly Roll Morton. The arranging style appears to be edited from line marked recordings. It is a syncopated and “hot” kind of low down South Chicago style of playing, which is consistently well done and equals the best blues arrangements issued by the Clark Orchestra Roll Company or the Capitol Roll & Record Company. The thing that makes National rolls somewhat unique, other than the fine arrangements, is a sophisticated expression coding put in the margins of the paper, although some might argue that the piano’s expressive capabilities were often less than fully exploited. The National pianos used a soft and loud pedal, like other coin pianos, but in addition it had a wide range of dynamics capable of going instantly from soft to loud and back again through manipulation of the stack vacuum level.
In 1925 the National Automatic Music Company and the National Piano Manufacturing Company merged and became the Automatic Musical Company (AMI). In 1931 the Michigan National Bank forced AMI into receivership. Under the bank’s direction they sought to eliminate the accumulating storage costs associated with pianos taken off routes and put in storage. The potential to revitalize these pianos by adding dog race dioramas or other amusement lures was no longer viable. “Juke-boxes” had become the rage and with that there was a dwindling demand for coin pianos.
The music roll production continued for another three years, even though private ownership of the National pianos had greatly reduced the demand for new music. After 1933, apparently, the Clark Orchestra Roll Company continued to supply new National music up until 1937. These Clark rolls were distinguished by a six-digit roll number proceeded by an “X” and the titles were written in pencil instead of stamped with a mimeograph type labeler as National had done. Both the National and Clark origin music roll were made on perforators using a 2-to-one master roll. The Clark perforators, however, had a slightly slower paper advance, which slightly increased the tempo.
This alternative National tubing and tracker scale diagram was created by Dana Johnson, circa 1968 - 1970 (during the time he lived in Denver, Colorado) and is reportedly representative of a National automatic piano for which he personally carried out certain repair work and then regularly serviced. The drawing is made available here because it may help to better illustrate how the various expression control components, working in conjunction with National built stacks, are tubed together and interrelated. And the story behind the drawing is interesting in and of itself and reveals a time when mechanical music collecting was still in its infancy. Please note, however, that certain tracker bar connections for expression controls shown in the diagram differ from the tracker bar scale published by Art Reblitz (and shown above on this page), which have recently been confirmed by a reliable source as accurate.
Gale Snyder (born in 1901) was interviewed in 1980 and he remembered working in the roll cutting department, running the perforator, from 1918 to 1921. He also recalled putting the words on the “8-T-8” player piano rolls by spray painting through a stencil overlay. He also printed the little tune strips that slipped into the tune card slots on the face of the 8-slot coin selection casting, using an old printing press.
Paul Estabrook’s arranging approach was to give his music a hand played feel and sound. He first used a line-marker and then laid the music out in steps to agree with the stepping system of the master roll. Jimmie Allen, another arranger, preferred to do all of his work “drafting board” style. This was done on a special master roll with sprocket holes on each side and with linear lines down the paper coded with the keyboard positions. He could draw the notes with a pencil, which would later be cut through by following it with a machine punch and pulling it into the confines of the 2-to-one stepping of the perforator.
The staff arrangers, Jimmie Allen and Paul Estabrook, each made several arrangements per week. There were other contributors: An old timer by the name of Walter Goebel did most of the march rolls; a Mr. Davies made blues arrangements, and Mr. Durnbaugh was the head of the music roll department. The perforator made fifteen copies at once. An earlier perforator had cut rectangular holes instead of the round holes of the newer perforator. As such, any rolls with rectangularly cut holes will be much earlier than rolls with the more traditional circular cut holes.
(Please note: In this music roll section, the majority of the historical information in the above text is a partial rephrasing and/or clarification of text originally authored by the late Durrell Armstrong.)
Most of the National automatic pianos studied to date (and for which serial numbers are known) fall within the 7,000 number range, along with a few confirmed specimens scattered in the 200, 300, 700, and 6,000 range. It has been noted elsewhere that by 1925 the National Automatic Music Company supposedly had some 4,200 pianos on location, spread over 180 routes in 32 different states. Although it is unknown what the beginning serial number might have been, the number span between the known pianos in the 200 and 7,000 serial number ranges far exceeds 4,200 pianos. A logical explanation for this broad mismatch is that the serial numbering system was skipped ahead to a new starting point one or more times, probably due to some yet unrecognized mechanical milestone or other evolutionary event significant enough to warrant such a drastic change. But what might have caused this kind of upset?
Here are some observed occurrences that might have, either singularly or in combination with some other event, justified a jump in a previously established serial number order:
Understanding the evolving mechanical improvements and precisely when a new design was commercially implemented is one of the goals of further research, but whether, or not, these design upgrades were important enough to generate a new piano serial number range is unknown. The one singular event that stands out as a potentially compelling reason to reset the serial numbering system is the 1925 reorganization of the National companies. But there may be other events, some revolutionary, that roiled the company that have yet to be recognized, and that propelled the serial numbering routine onto a new path. Until many more National pianos can be surveyed, covering a broad range of serial numbers from beginning to end, the precise evolutionary change that pinpoints a serial number reset will probably remain a mystery.
Art Reblitz thinks it is likely that National began a new numbering series at the same time the company introduced a group of major mechanical design changes that required different repair parts—possibly when the company changed from spring barrels and cast iron parts to torsion springs and die-cast parts, assuming these changes might have happened at the same time. That way, when an operator had to order a replacement part, the serial number series would tell the factory which style of part to send out, without looking up the specific serial number in a log book. This same logic might also apply to music rolls, in as much as the revolver magazines equipped with the spring-barrel rewind system did not need pre-spooled rolls, whereas magazines equipped with the later torsion spring rewind system required interchangeable pre-spooled rolls. Moreover, in light of the large number of Nationals that were destroyed, it seems logical that most survivors would be the newest ones that were still in better working condition, which would have higher serial numbers. To me, it seems possible that the original numbering series only got to around 1,000 or 1,200, and that they started the new series with 5,000. That would theoretically cover 1,000 + 3,000 pianos, almost equaling the 4,200 pianos that were supposedly made by 1925.
Mechanical music research is commonly limited to hazy memories, inaccurate word of mouth recollections, and/or oftentimes poor-quality photographs, which, when taken all together, can make it difficult to correctly differentiate between factory original and non-factory alterations. With this in mind, a significant number of National pianos have been identified with what looks like either a felt muffler rail, or a typical curtain type mandolin attachment, or simply a bare metal rod that can be manually lowered and raised but that is devoid of any apparent musical use. And so, considering the uncertainties, did some National pianos come with factory installed muffler rails, while others were fitted with mandolin attachments, or was only one of these things ever factory installed? Taking into account these factors, the most logical conclusion seems to be that it was a muffler rail that was originally installed, which makes good sense for the following reasons:
To actuate the muffler rail (or mandolin effect) there is a machined metal knob with a knurled rim that is located on the right-hand side of the piano case a few inches down from the top edge. Turning the knob clockwise lowered the rail, while turning it counterclockwise raised it, and if turned far enough, passing the over-center position, it was locked in the upward disengaged position. On the rail itself, over each piano action bracket bolt there is usually some action felt wrapped and secured firmly around the metal rod, so that when it was lowered and if it bumped up against the action bracket bolts there was no metal-to-metal clanking noise, keeping the muffler/mandolin rail operation silent. Of course, some muffler rails could have long ago been modified or converted by a route operator or some more recent rogue mandolin attachment fanatic. But whatever the case, of the relatively small sampling of attachment rails noted to date, and that look professionally crafted and original, rather than being a kludged together adaptation, they have either a felt muffler curtain glued to the rail, or a mandolin curtain glued to the rail, or the rail (a round metal rod) is essentially bare.
Exactly how many National pianos originally had a muffler rail (or mandolin attachment) installed is unknown, and will probably forever remain a mystery. This is because there are no factory records to examine, and there is neither sufficient photographic evidence nor a large enough sampling of surviving National pianos to predict a quantity or percentage with any sense of accuracy. Adding to the mandolin attachment confusion, some of those reported are said to be automatic, in that they have a pneumatic mechanism installed that lowers and raises the mandolin attachment, casting further doubt on the originality of the installation. It would be easy to convert a felt muffler curtain to a mandolin attachment, by simply ripping off the muffler felt and gluing on a typical curtain type mandolin effect. Unfortunately, it is often difficult or next to impossible to ascertain the originality of a muffler rail or mandolin effect installation without personally being able to carefully examine and touch the piano in question.
Anyone able to shed more light in this subject is invited to share their knowledge at:
There are at least two types of pneumatic stacks known to have been factory installed in National coin pianos, (1) the commonly observed National built stack and (2) a seldom seen Simplex style stack. Both are visually quite different, making them unmistakably easy to identify. The National built stack is open with all of the unit control valves and/or unit (piano) pneumatics visible and easily removed and serviced from the front, while the Simplex stack is semi-enclosed, with none of the valve units visible from the front, or even removable without first taking off the front cover, which forms the vacuum chamber that feeds the individual unit valves. Even then, the stack needs to be completely removed from the piano to easily service the valve assemblies.
But there is possibly one more stack type that might be encountered. These are late, circa 1928, Unitype stacks, bought from an outside supplier, and while it is reportedly possible that a National piano might have been factory retrofitted with one of these single-tier stacks, no such retrofits have, as of this writing, reportedly been observed in the wild.
The National Piano Manufacturing Company built pneumatic stack is what is commonly found installed in National coin pianos. It consists of a rather standard looking wooden framework that supports three tiers of unit valve and pneumatic assemblies. There are 24 units making up the top row; another 24 on the middle row, and just 23 on the bottom row, for a total of 71 units. There are also 71 holes in the tracker bar, but tracker bar hole #1 for accent (or Sforzando) goes to the spill valve regulating pneumatic, and not to the stack. This leaves one unit valve control assembly unused for some other non-tracker bar related function, for which this “extra” valve pouch is connected to the rewind trip pallet valve, which opens when a lever riding lightly over the music roll paper falls into the rewind cutout at the end of the music roll.
The 6 stack unit valves devoted solely to control functions are located on the left side of the stack, and populate the two left-side outermost spaces on each of the three tiers, while all other positions are for unit pneumatics that play piano notes. Notice the difference in terminology used: Unit valves and unit pneumatics. The 6 special unit valves used for control functions do not have pneumatic bellows attached to the bottom of the valve assembly, but instead have a single spacer block of wood with a 3/8 inch hole drilled through to the rear facing side. This hole is fitted with a brass elbow tubing connector, which is in turn connected via rubber tubing to whatever control function pneumatic is appropriate. These control valves perform the following functions: Hammer rail up (and latched up), hammer rail down (locking latch is released), soft vacuum level on, soft vacuum level off, sustaining pedal, and rewind.
Each of the 71 valve units are firmly held in place by threaded metal studs inserted into the stack framework and that are positioned between the valve units, each with a metal washer and nut on the outer end of the stud that can be tightened to hold the valve units in place. These stacks are easily identified by the individual rubber tubes from each of the value units converging on the area of the tracker bar, resulting in what might appear to be a hopeless tangle of rubber tubes.
From a structural viewpoint, the vertical wooden supports on either side of the stack are notably different. The left leg is structurally complex and consists of a foot and attached vertical structure, both of which have internal channeling to distribute vacuum to the three horizontal tiers of unit valve assemblies. The other vertically oriented leg, located on the right-hand side, is simple in comparison, is without any hidden channeling, and serves only to physically support one end of each tier.
These stacks, at quick glance, might all look to be the same or, at the very least, quite similar in appearance. Upon closer look, however, there are some obvious but perhaps not immediately eye-catching differences, such as variances in the wooden spacer blocks that take the place of omitted unit pneumatics where divisions in the piano string sections and/or piano action brackets occur, and, perhaps much more significantly, in the design of the stack’s main structural framework. For instance, end legs and their foot design can vary, and with more information these differences might be useful in understanding the evolution of National automatic piano mechanisms.
The Tilting Yoke Atmospheric-Port Bleed Type Control Valve is the vacuum expression methodology used with the commonly observed 3-tier National built pneumatic stacks.
Simplex style stacks all share at least two traits: (1) the unit valve design (i.e., unit control valves and the unit pneumatics that play piano notes), and (2) the generalized trunk board hole pattern layout, to which the various unit valve assemblies are attached by a pair of wood screws. But there are also necessary differences that must be accommodated between various player systems and the piano plate scales that will inevitably be encountered. For instance, the trunk board width and the precise layout of valve attachment holes will vary with different piano plate designs, which may group and space the piano strings in similar looking patterns but that require spacing adjustments in the trunk board layout. It is well known that Simplex manufactured a wide variety of stacks with special spacing requirements for many competing player piano brands, and to a lesser extent for coin pianos. And so, was National a big enough customer to warrant a special Simplex stack, ready to mount in a National piano? Or did National purchase some basic Simplex components and finish the work of laying out and building the stack themselves? In as much as there is currently too little evidence to definitively answer this kind of question one way or another, let’s bypass it for now and assume that the Simplex style stack, as installed in National automatic pianos, was made in its entirety by Simplex, but installed, more or less as is, by the National Piano Manufacturing Company.
For sure, the 3-tier Simplex style 65-note stack design used by National bears no visual resemblance whatsoever to the more commonly found 3-tier National built 65-note stacks. Although both stacks provide unit pneumatics for 65 piano notes, along with 6 unit valves dedicated to various control functions, that is pretty much where the similarities end. The unit pneumatics are basically divided into three groups, the dividing line coinciding with the string divisions in the piano plate. There are 14 individual unit pneumatics in the bass section, 32 in the middle section, and 19 in the treble section, for a total of 65 playing piano notes. Curiously, the Simplex stacks examined are laid out to accommodate National pianos with 32 notes in the mid-section of the plate, whereas all of the pianos examined with National built stacks have only a 30-note mid-section plate design. This implies that Simplex stacks may have only been installed in a select production run of National pianos fitted with a specific piano plate design, and perhaps with their own serial number range, making these pianos structurally different from the common variety seen today that have National built stacks. This perhaps trivial seeming difference between the two types of piano plate styles might someday turn out to be a solid clue as to what National was building during its earliest years.
The Simplex stack is built around a central trunk board, which is 3-tiers high and with a width that is somewhat more than enough to accommodate the string layout on the piano plate. It is this trunk board to which all of the unit valve assemblies are fastened, whether they be for playing piano notes or carrying out some important control function. As the name implies, the trunk or channel board feeds necessary resources through channels to the attached unit valves, so that they are functionally useful, such as connecting a tracker bar signal to the appropriate unit valve, or providing a vacuum source to each valve. Additionally, the trunk board is accurately drilled to hold each unit valve, using a pair of wood screws, firmly in its correct position. Covering and protecting the trunk board is a removable wood panel that has a framework around its outer edges, so as to form an air-tight cavity or compartment once the cover is affixed over the front side of the trunk board. The cavity formed by the cover is then connected to a source of vacuum, which, in turn, provides a vacuum source to all the attached unit valve assembles. This design is elegantly simple and durable, but has its drawbacks. To remove any unit valve for servicing the front cover must be removed first in order to access and unscrew the pair of wood screws that hold it attached. But then, once the unit valve is loose, that stack must still be taken out of the piano to gain easy access to the unit valve assemblies.
But there is more to the stack than the trunk board and its front cover, because it needs to be held rigidly upright and in the correct position. This is accomplished by hefty and blockish wooden vertically oriented sections at each end of the stack, also adding depth to the stack approximately equal to the length of the individual unit valves sticking outward on the backside of the trunk board. The end pieces also support a top shelf, to which is attached a wooden rail with 65 wood flanges, each flange acting as the pivot point for a movable finger that is raised at its outer end by a piano pneumatic. This finger also has a capstan screw near the outer end used to adjust the contact height with the piano action, so that the stack accurately conforms to the piano action wippens, thereby eliminating any lost motion between the stack components and the piano action. This self-contained arrangement makes it relatively easy to slip the entire stack out of the piano for servicing, and then put it back in without undue effort.
Screwed to the front side of the stack, and to the left of center on the trunk board cover, is a large block of wood bored and channeled to accommodate the needs of a poppet type spill valve, which is controlled by the cam-work on the Rewind/Play control system located to the left of the roll changer and mounted on the flat “keybed” area shelf. This spill valve is either wide open or closed tight, and it possess no vacuum regulation capabilities at all. Near the left side of the front cover there is a medium sized elbow jutting out with a rubber tube that curls upward toward the top of the piano action. The elbow is inserted into the vacuum cavity made by the trunk board cover, while the rubber tubing connects to the tune indicator mechanism to the left of the piano action, and in particular to the pneumatic that raises the metal shutter that reveals what tune is currently being played. Moreover, if the piano has been retrofitted with a dog race diorama, the rubber tube is teed to also connect with a small valve chest under the race track area.
The Balance-Beam Design (with Coil Spring Balanced Ventil Valve) is the vacuum expression methodology used with Simplex style pneumatic stacks.
In the writings of the late Durrell Armstrong it is mentioned that some National automatic pianos were retrofitted with Unitype pneumatic stacks. These were a single-tier stack with a row of narrow unit pneumatics that faced forward, and that had a metal spoon attached to the rear end that lifted a piano wippen when the pneumatic collapsed, causing the piano note to sound. And so, it may be that some National pianos were retrofitted with a Unitype stack, either by the factory or by some route operator. But if such retrofitting did in fact occur it cannot currently be verified by any original factory or other documentation, and so it remains hearsay. Moreover, no extant National pianos fitted with a Unitype stack have been observed, reported, or rumored to date. Nevertheless, an example might someday be discovered, and so to become familiar with Unitype stacks please click on the patent illustration thumbnail at right.
Anyone able to provide information regarding the retrofitting of Unitype pneumatic stacks in National automatic pianos is invited to share their knowledge at:
There are at least two types of pneumatic volume expression control devices observed in National automatic pianos. The first, which we have arbitrarily named “Tilting yoke atmospheric-port bleed type control valve” is the type commonly observed in most of the National coin pianos that survive to this day. Moreover, it is an indispensable companion for the National built 3-tier pneumatic stack. Whether, or not, our terminology for this expression control system bears any resemblance to what the National Piano Manufacturing Company originally called it will probably forever remain a mystery.
The second kind of volume control device used a “balance beam” type of regulated spill valve, which was integrally built into the left-side structural protruding foot of Simplex style pneumatic stacks. A separate board with paired lock and cancel pneumatics (for high vacuum on or off) was butted up against the balance-beam mechanism and was attached by a threaded adjusting screw to one end of the wooden balance-beam. This system is much simpler to regulate, but has no provision for the accent (or Sforzando) hole #1 on the tracker bar.
It is important to keep in mind that the vacuum expression control system is a critical part in any National automatic piano, no matter whether the expression device be made by National, Simplex, or someone else. This is because the expression system not only controls the vacuum soft/loud levels, but it also acts as the safety spill valve for the pump. The vacuum system in National pianos has no customary vacuum reservoir with a traditional spill valve. This means that the expression control’s spill valve must be capable of safely accommodating no less than the maximum airflow passing through the vacuum pump, otherwise damage to the pump bellows and/or connecting rod links may occur due to being overloaded and/or stressed to the breaking point.
To recap, here are the two pneumatic expression control variations observed to date:
This commonly observed expression control system could perhaps better be described as two different but interdependent and equally important components, each quite different in appearance, construction, and purpose. The most obvious component, and usually the first and only part of the system easily seen and recognized, is what I have been referring to as the “tilting yoke atmospheric-port bleed type control valve,” a long and cumbersome name perhaps, but one that describes the unit quite nicely. The name is derived from the obvious and centrally located tilting yoke, the lower tail end of which opens or closes an atmospheric-port that bleeds off and reduces the output vacuum level of the unit. The expression control unit sits at the far left of the “keybed” area, usually mounted on top of the stack’s left-side foot, but occasionally it has been seen mounted on the “Keybed” area in front of the stack foot. The other part of the expression system is the regulated spill valve, which is usually mostly hidden behind a mat of rubber tubing that connects the tracker bar with the 3 tiers of individual unit valve assemblies on the stack.
The so-called “tilting yoke” unit consists of an aluminum block with a wide channel cut into the top. Secured to each side of this channel is a narrow pneumatic that faces forward. These two little control pneumatics are used to alternately tilt a thin brass yoke (located on the front of the aluminum block) one way or the other—the yoke pivoting about a machine screw. The tail or lower end of this brass yoke either blocks off or exposes a small port or orifice, which has been drilled into the front side of the metal block. This small port connects internally with a much larger diameter channel drilled through the block from side to side, for which the vacuum supply is connected to its inlet connection on the left side; the right side being the outlet for the unit. There is an adjusting screw into this main vacuum channel located between the inlet and center air bleed port, whose sole purpose is to restrict the airflow allowed through the main vacuum channel. Another adjusting screw located on the right-hand side of the aluminum block is used to adjust the airflow through the small atmospheric port.
The main side-to-side vacuum channel delivers at its right-hand side outlet a variable output vacuum level that depends upon (1) the position of the brass yoke, which either closes or exposes the atmospheric port, and (2) the two adjusting screws which regulate the airflow rate within the device. The output is connected via a rubber tube to the regulating pneumatic making up the other half of the expression system, and that is an independently situated regulated spill valve unit. This spill valve component is described as regulated because it acts to both regulate the vacuum level throughout the player system, and to serve as the vacuum dump valve during the rewind and roll changing operations.
The regulated spill value unit consists of a die-cast pedestal that serves not only as a mounting platform for a suspended medium sized control pneumatic, but also as the actual spill valve face itself. Directly over the spill valve face is the suspended pneumatic (using a metal bracket attached to either side of the die-cast pedestal). The top side of the pneumatic is fixed to the metal bracket and therefore stationary, while its bottom movable leaf, which is partially covered with a suitable valve leather, is free to relax and fall open and rest flatly on the spill valve face, thereby forming an air-tight seal.
To make certain that the regulating pneumatic will tend to stay firmly seated on the spill valve face, an internal but adjustable compression type spring is used to push the movable leaf of the pneumatic downward. To make this internal compression spring easily adjustable, on the top side of the pneumatic toward the front, there is a partially hollowed out brass stem that sticks up. The upper part of the compression spring slips into the hollowed-out area of the stem, and through the top of the stem is a threaded hole for a machine screw, which can be screwed in or out, thereby adjusting the spring tension pushing down on the lower movable leaf of the pneumatic. Occasionally the machine screw is unembellished, bare for all to see, but more often than not it is combined with a knurled brass cap-sleeve, or cuff, that facilitates the easy adjustment of the spring tension upwards or downwards by gripping and then twisting the outer sleeve one way or another. When the piano is in play mode, this spring tension, working in conjunction with the airflow adjusting screws on the “tilting yoke” mechanism, will determine the “at rest” player system vacuum level. Except, of course, during the rewind and roll changing phase, when the regulating pneumatic is mechanically raised by a cam operated lever, so that all vacuum is spilled whenever the tracker bar is raised away from a music roll.
While it may seem counterintuitive at first, the higher the vacuum level in the regulating pneumatic the lower the overall player system vacuum level, which directly affects how soft or loud the piano plays. Because of the restricted airflow on the vacuum inlet side of the “tilting yoke” unit, when the atmospheric bleed port is open the vacuum level at the outlet side, which is applied to the regulating pneumatic, will be relatively low, due to air bleeding into the exposed bleed port. Thus, the bottom movable leaf of the regulating pneumatic will only be gently pulled away from the spill valve face, and so the system will balance out with a relatively high vacuum level. Conversely, however, when the atmospheric bleed port is closed the vacuum level in the regulating pneumatic will rise, because no vacuum is being bled off through the bleed port. This causes the regulating pneumatic to more vigorously work at pulling the movable leaf of the pneumatic upwards and away from the spill valve face, which, once the system reaches a new equilibrium, will result in a lower vacuum level.
On the top side of the regulating pneumatic is a second but smaller brass fitting. It is connected directly to tracker bar hole #1, which is used for accent (or Sforzando) effects. When air rushes into the accent hole through the tracker bar the vacuum level in the regulating pneumatic is almost instantly lowered (as a consequence of those airflow limiting adjusting screws in the “tilting yoke” device), thereby lessening the tug trying to pull open the spill valve. This has the immediate effect of momentarily raising the overall vacuum level throughout the player system, thereby providing an accent to the piano melody.
Out the backside of the die-cast spill valve pedestal is an approximately 1-inch diameter tube fitting to which is attached a rubber hose. This hose is teed into the main vacuum supply hose going between the vacuum pump and the pneumatic stack. There is no vacuum reservoir in National coin pianos, although it is something commonly used by other coin piano manufacturers to smooth out the periodic fluctuations in airflow due to the physics of how bellows type pumps are constructed. Consequently, the spill valve in National pianos must regulate not only the desired vacuum level, but it must also reliably spill and relieve the constant pulsing caused by the rotary pump, along with any excess vacuum that may be generated by the pump, otherwise, if the vacuum level were to go too high the pump could be severely damaged.
But there is more to consider here, because of the compound duties of the regulated spill valve it is imperative that the two airflow limiting adjusting screws in the “tilting yoke” unit, as well as the spring tension in the spill valve pneumatic, be properly adjusted. And, as should be obvious, these three adjustments, which are spread across two separate components, are closely interrelated, with any adjustment of one affecting the other two. This begs the question: How does one go about adjusting these three items for maximum effectiveness? It would be wonderful if we could simply refer to an instructive pamphlet by the National company itself, but no such thing is known to exist. Thus, some deductive reasoning seems appropriate, although it may not achieve the exact same result as originally sought by the National Piano Manufacturing Company.
Here are some ideas regarding the adjustment options utilized by the vacuum expression control: Please consider any methodology expressed here as experimental, subject to change, and never any kind of official or perfected way of adjusting the vacuum expression system. Moreover, everyone will probably have differing ideas as to what constitutes an ideal level of performance. Nevertheless, let’s start exploring the subject by noting what the three adjustment options are, how they function, and why:
Of course, it almost goes without saying, any adjustments made will probably require some patient back and forth twiddling before the desired perfection in vacuum expression levels will be achieved. And much of that success will depend upon the quality of any restoration work performed on the player mechanisms. For instance, any player system full of leaks and fettered by some poorly working components will never perform satisfactorily, no matter how you might adjust the expression controls. Possible reasons for troubles abound, but are often simply because the pump, regulating valves, and certain air passageways are simply overwhelmed due to the sheer volume of air they are required to process. This overload, in turn, causes other previously operational but now compromised components to act sluggishly or become unresponsive altogether, all because some leak strewn player system forces crucial components well beyond their design capacity.
The Simplex style balance-beam type expression control is visually simple and intuitively easy to understand and adjust. The ventil or spill valve and its mating metal seat is located on the topside of what casually looks to be an extended foot for the stack’s left side structural support. This foot extension has a vacuum channel partially through it (interconnecting it with the spill valve cavity), which is part of the internally channeled vacuum supply system that feeds each of the stack’s three tiers of unit valve assemblies. The circular metal seat is held fixed in place by two small wood screws, the metal seat being directly above the actual ventil or spill valve, which can freely move up and down within the valve cavity. When a vacuum is applied to the valve cavity the spill valve body will naturally be pushed down and open by atmospheric pressure, unless, and to the extent that an upward balancing force is applied to the valve body. This is where the balance-beam apparatus comes into play. The beam is supported mid-point by a sturdy cast brass stanchion, that also serves as the pivot point for the balance-beam. The brass stanchion is mounted on the stack foot extension near the spill valve, but also located midway between it and a pair of lock and cancel pneumatics mounted side-by-side on an adjoining wooden board that has internal channeling to provide tubing connections for the two control pneumatics.
A vertically oriented hole is drilled near each end of the balance-beam, through which is placed a threaded eyelet that is adjustable up or down using leather nuts. One end of the balance-beam is connected to the spill valve by a coiled extension spring, while the other end is connected to a wide control pneumatic that once activated locks in the down position until unlocked by another but narrower pneumatic at its side. With the wide locking pneumatic fully relaxed, or open, the spring tension on the ventil valve is adjusted to provide an ideal low vacuum level (piano soft). Then when the wide locking pneumatic is activated and latched down it pulls the balance beam down with it, in turn raising the other end, which then increases the spring tension on the ventil valve, thereby causing the vacuum level to rise (piano loud).
The balance-beam spill valve in this type of expression system must have sufficient spill capacity to handle the entire airflow volume generated by the vacuum pump, otherwise excess vacuum could not be relieved, causing the vacuum level to rise beyond safe levels and possibly damage the pump. However, the balance-beam type spill valve used with Simplex stacks does not do double duty, i.e., regulating the vacuum level plus act as a vacuum dump valve during the rewind and roll changing operations. To dump the vacuum a separate, non-affiliated poppet style dump valve is attached to the front cover of the Simplex stack. This large volume capable valve is operated by one of the cams on the Rewind/Play camshaft.
Oddly enough, the balance-beam system offers no provision whatsoever for the accent (or Sforzando) perforation in the music roll (tracker hole #1), which is left unused on the tracker bar. This omission has served to cast doubt on the originality of the balance-beam device. Was it factory installed by National, or was it installed by someone else? The consensus at this time is that the balance-beam vacuum expression system is integral to the use of a Simplex style stack, and was therefore likely factory installed along with the stack.
Adjusting the balance-beam unit is intuitively easy, it being so simple in both theory and construction that correctly optimizing its operation requires no heady instruction sheet or hand-holding to enjoy successful results. It is, however, important to remember that the minimum vacuum level to be allowed must always be a level at least a little above the point whereby the stack unit valves begin to function unreliably, first symptoms often being certain piano play weakly, or have lost their repetitive accuracy, or do not play at all. Moreover, any valve reliability issues will be exacerbated when the player system is full of leaks and malfunctioning but not necessarily crucial components. Suffice it to say, the Simplex style stack associated balance-beam expression control is probably one of the easiest components in a National coin piano to restore, adjust, and then maintain.
The hammer rail (soft pedal) is controlled by a pair of interlocking motor pneumatics located in the upper left rear corner of the case, directly above the piano action. Both pneumatics are mounted on the same wood block, which is screwed to the inside of the piano case. The lower pneumatic lifts the hammer rail and when fully collapsed a spring loaded and felted wooden hook falls over a metal blade and latches the pneumatic in the upward closed position. At this point the hammer rail (or soft pedal) is locked in the raised (or soft pedal on) position. The smaller upper pneumatic, when caused to collapse, pushes the wooden hook off of the latching surface, allowing the hammer rail to fall back (of its own weight) to its normal rest (soft pedal off) position.
The sustaining or loud pedal is located on the left side of the “keybed” area behind the left foot of the stack. It is operated by a single pneumatic that is mostly obscured from view by rubber tubing and the stack foot. It functions by pushing upwards against a sturdy lever that is part of a round metal rail running the length of the piano action, which, in turn, lifts the piano dampers from the piano strings. Unlike the hammer rail (or soft pedal), there is no lock and cancel system for it, but simply a single chain perforation on the music roll, which when present causes the sustaining pedal pneumatic to collapse, lifting the piano dampers.
There are two known but fundamentally different revolver magazine configurations Patented by the National Piano Manufacturing Company, one with a stationary tracker bar and the other with a movable tracker bar. Both types have carriers (or roll stations) for eight music rolls. The first and very early style revolver magazine had a stationary tracker bar coupled with a magazine that slid toward or away from the tracker bar on two horizontal rails. The Patent, No. 1,217,271, titled Automatic Musical Instrument with Magazine, was filed on July 18, 1912, and finally granted on February 27, 1917. Disappointingly, there are no known extant National pianos with this type of revolver magazine arrangement. Consequently, the only reliable information regarding this horizontal sliding type is from the Patent application, and so this type of revolver magazine will not be detailed in this writing. Click here to view Patent Application No. 1,217,271.
The second type of revolver system utilized a movable tracker bar with the revolver magazine axis journaled in stationary bearings (below the “keybed” area) and fastened to vertical structural components of the piano case. Initially the tracker bar moved back and forth horizontally; not the revolver magazine, as in the previously mentioned Patent. The Patent, No. 1,068,217, titled Automatic Piano Player Having Self-Settings Device was filed on August 7, 1912, and granted on July 22, 1913. Click here to view Patent No. 1,068,217. And like the sliding revolver magazine, no examples of a revolver setup with a horizontally moving tracker bar are known to exist. It is a relatively short evolutionary jump for the idea of a horizontal tracker bar to be reoriented so that it moves up and down vertically, a simple change that substantially reduces the depth of the piano case. Now you have a revolver magazine system that could very well be the start of an evolutionary outcome that is universally observed in the typical National automatic piano still enjoyed by collectors today, and that is the configuration that is covered extensively in this writing.
Almost certainly, the revolver (roll changer) magazine and its associated intricate control mechanisms are usually the most eye-catching mechanical feature of the National Automatic Piano. Moreover, when the numerous scattered but closely interrelated components are all lumped together into one whole system it might seem to be an unfathomably complex mechanical nightmare. However, when the apparent complexity is broken down into logical units of basic functionality there is a beautiful simplicity that is easy to see, appreciate, and comprehend. To begin sorting out the various functionally unique sections, the revolver (roll changer) magazine can be categorized as a separate cluster of associated parts whose sole purpose is to hold eight music rolls (each with its own personal take-up spool and spring-loaded rewind gearing) and then, on command, rotate on its axis until stopped when the desired music roll is situated beneath the tracker bar. The revolver assembly reliably performs this function but no other, and its action is coordinated by the two separate but interconnected control systems mounted on either side of it on the flat “keybed” area of the piano.
Temporarily setting the revolver magazine aside, the “keybed” area revolver controls can easily and logically be further divided into (1) the Rewind/Play mode functions located on the left side of the revolver, versus (2) the music roll selection functions located on the right side. Both sides and the functions they carry out are equally important. If either a left or right-side mechanism fails to perform its mandated duties correctly, or in a timely manner, the player system will be rendered inoperative. The logical divisions noted here apply to all National coin pianos, no matter whether they are equipped with a National built or Simplex style stack, and/or have either certain cast iron or die-cast components, such as for the worm gear clutch housing casting.
First, we will deal with the Rewind/Play mode control system, followed by a detailed explanation of the music roll selection mechanisms, which are located over on the right-hand side. Once these two spatially separate but interconnected control systems are understood adding the revolver mechanism to the mix will be an easy next step, with the process building toward a useful comprehension of how the three functionally independent but related systems work, interconnect, and why.
First off, the so-called “Rewind/Play” term is a convenient simplification, a space saving contraction for the more explanatory “Rewind/Roll Changing mode versus the Play mode” And the frequently used “Rewind/Roll Changing mode” terminology is a reminder that the “rewind” and “roll changing” modes always occur simultaneously, and are essentially one and the same thing. The rewind mode for any music roll automatically occurs when the tracker bar and take-up spool drive gear are lifted away from the revolver magazine, which is the same mode in which roll changing operations are allowed to occur. The player system is either in the Rewind/Roll Changing mode or it is in the Play mode, and it is always powered off and later powered back on while the system is in the middle of a Rewind/Roll Changing mode cycle.
It may be that the Play/Rewind interrelated clutch, gearing, and camshaft segments might look intimidating at first glance, but analyzing the whole thing bit by bit quickly reveals the easy simplicity of the entire unified assembly. To do this, let’s start at the left end and work our way to the right side. All of the Play/Rewind system components to be discussed are mounted on a single underlying metal plate, which keeps all of the attached components precisely aligned, more so than would be the case if the same components were mounted directly onto the underlying “keybed” area wood shelf.
But before going further let’s define what a cam and a cam follower are:
Next is another important concept to grasp, and that is to understand that the rotational functions of the camshaft are divided into two distinct 180-degree rotational segments. In other words, each one-half revolution of the camshaft performs a different set of functions—either putting the player system into the Rewind/Roll Changing mode or into the Play mode. And after each one-half revolution the camshaft rotation is automatically and abruptly stopped at a precise point, until triggered again and the next one-half revolution occurs. If and when all is working as designed, whenever a coin is accepted by one of the eight numbered coin slots, and it then falls into the coin switch mechanism, the electric motor is powered on, and with the tracker bar in the raised position and the revolver magazine rotating to position itself so that the selected music roll will be put under the tracker bar. Thus, the camshaft is temporarily positioned in what could be called the Rewind/Roll Changing mode, a state invoked earlier when the rewind pallet dropped into the cutout at the end of a music roll, whereupon the tracker bar was then quickly lifted away from the music roll and the music roll began rewinding.
When the selected music roll is correctly stationed under the tracker bar the camshaft drive clutch is engaged, causing the camshaft to rotate one-half revolution and stop, putting the player system in the Play mode. When this camshaft activity occurs, the tracker bar is lowered onto the music roll, the revolver magazine is locked into position, the vacuum spill valve is allowed to close, and the spur gear that drives the music roll take-up spool is engaged, with some toe-tapping piano music soon to follow. The camshaft sequence is always the same (1) Rewind/Roll Changing mode when the system is powered on, (2) switching to the Play mode when the selected music roll is correctly positioned, and then (3) back to the Rewind/Roll Changing mode at the end of the music roll, when the system is either powered off or the next selected tune is played in succession. (Music roll rewinding is accomplished using a torsion spring system built into each music roll station on the revolver magazine.
Because the Rewind/Roll Changing mode is the rotational position of the camshaft whenever the player system is powered on, let’s define the Rewind/Roll Changing position to always be the starting point when describing the revolver magazine and its controls. To sum it up:
With some generalities out of the way, here is an enumeration of the individual camshaft components working from the simple left side trigger pneumatic over to right side, with the largest cam that raises and lowers the tracker bar assembly.
Rotation of the camshaft is triggered in one of two ways. The first method has been detailed above in paragraph #1, which explains the functionality of the Rewind/Play trigger pneumatic. When activated, this lone pneumatic unlatches the cam follower lever under the Rewind/Play cam, which allows the camshaft clutch to engage, rotating the camshaft one-half revolution before it is again stopped. During its momentary activity, the camshaft reconfigures the player system, taking it from the Play mode to the Rewind/Roll Changing mode. However, to reverse this action, i.e., to go from the Rewind/Roll Changing mode to the Play mode, requires a different way of triggering the clutch action—namely because the spill valve will still be fully open, dumping any vacuum, thereby rendering the trip pneumatic useless. And so, to bypass the problem a direct mechanical link to the coin switch mechanism is used. This is accomplished by using an alternate trip lever, which is attached to the smaller diameter shaft that traverses the front of the “keybed” area (and is placed inside the hollow but larger diameter shaft), and that terminates with a small bell-crank located inside the coin switch enclosure.
When the coin mechanism is activated by a coin, and the player system powers up, it will be in the Rewind/Roll Changing mode. Then, as the revolver magazine rotates, the studded selector cylinder in the coin switch enclosure rotates in synchronicity with it. When the rotational position of the studded cylinder signals that the selected music roll is located under the tracker bar, the trip lever (in front of the Rewind/Play cam) alternately pushes down onto and releases the cam follower lever, thereby engaging the clutch, putting the player system into Play mode. (Note that there are two control shafts that traverse the “keybed” area, a smaller diameter “Play mode trip” shaft that goes through the hollow and larger diameter “coin switch reset” shaft.)
It is important that the exact rotational position of the studded selector cylinder in the coin mechanism and the revolver magazine be correctly aligned. If the tracker bar drops too soon the locking hook for the revolver magazine will ride over the top of the locking wheel for some distance and then suddenly drop into a slot. This drops the tracker bar frame with a bang. When the timing is adjusted properly the tracker bar frame will begin to descend just prior to the point whereby the locking hook is approaching the leading edge of a slot in the locking wheel, allowing the tracker bar frame to be lowered onto the music roll in one smooth flowing motion—without any adverse mechanical jarring and cringe-inducing noise.
The music roll selection controls to the right of the revolver magazine are less complicated looking than the Rewind/Play camshaft system on the other side. There are only two separate but interrelated major component assemblies that share the workload of getting the selected music roll correctly positioned under the tracker bar. First there is the simple eight tooth clutch mechanism that drives a round leather belt pulley, for which the belt then wraps around a much larger metal pulley affixed to the main axis of the revolver magazine.
Operation of the so-called tooth clutch is simple: When the tracker bar frame is raised up (while the Rewind/Play camshaft is in the Rewind/Roll Changing mode position) the tooth clutch is engaged, causing the revolver magazine to rotate whenever the electric motor is powered on. Conversely, when the tracker bar frame is lowered (when the player system is in the Play mode) the tooth clutch is disengaged, during which time the revolver magazine is then rotationally locked in place.
There are two halves to the machined brass tooth clutch: First is the loose or driven one-half of the clutch, which is firmly attached to the belt pulley. The belt pulley can spin freely on the clutch shaft, unless the tooth clutch halves are pushed together, whereupon the clutch is then considered to have been engaged. The other half of the tooth clutch is cut into one end of a brass sleeve (the shifter assembly) that can slip back and forth on the clutch shaft but that is keyed to the shaft, so that it must always rotate along with it. The position of the movable shifter sleeve is determined by a yoke that is attached to a lever that is, in turn, connected by linkage to the tracker bar framework. When the tracker bar frame is raised the tooth clutch is engaged, and when the tracker bar is lowered the jaw is disengaged.
For certain pianos, and possibly all of them with a Simplex stack, the tooth clutch shaft is supported on each end by cast iron bearing posts, with another bearing post to support the lever and yoke that engages and disengages the clutch. And there is yet another (or forth) adjacent cast iron bearing post, this one used to support the near end of the long shaft that synchronizes the revolver magazine with the studded selector cylinder located inside the coin switch enclosure. However, for most pianos associated with National built stacks, a single die-casting takes the place of the four separate cast iron bearing posts, one casting supporting (1) the clutch shaft (and everything on it), (2) the activating lever and yoke for working the tooth clutch shifter sleeve, and (3) the bearing support for one end of the shaft used to synchronize the revolver magazine with the studded selector cylinder within the coin switch enclosure. This multi-purpose die-casting is mounted directly on the wooden shelf that makes up the “keybed” area. No underlying spacer or metal mounting plate is necessary in this instance, because any critical alignment necessary between the various working parts are suitably maintained by the single die-casting.
The second crucial component in the roll positioning process is the studded selector cylinder located in the coin switch enclosure, which must be precisely synchronized with the rotational position of the revolver magazine, something accomplished by means of a non-slip chain and sprocket arrangement. Tune selection for a National piano is accomplished by dropping a coin into one of eight different coin slots, one for each of the eight music rolls mounted on the revolver magazine. Correspondingly, there are eight rugged studs (which are adjustable in height) mounted on the studded cylinder, with each stud located on a different track spread across the length of the cylinder, and each track assigned to a particular music roll. As such, each stud represents the exact rotational position the revolver magazine must attain for the tracker bar to be perfectly lowered over the selected music roll. So, when a tripped cam finger for a selected music roll contacts the corresponding stud, and is pushed downward, the Rewind/Play camshaft clutch is engaged and the player system immediately goes into Play mode. In contrast, when the end of the music roll is reached, and the rewind pallet valve drops into the rewind cutout, the player system switches from Play mode to the Rewind/Roll Changing mode, raising the tracker bar and engaging the tooth clutch. When this occurs the revolver magazine will begin rotating, and, if no other tunes have been selected, it will immediately begin slowing down to a stop, following the electric motor which has been powered off and stopping. Now the player system is set for the next coin drop, with the tooth clutch engaged and ready to continue rotating the revolver magazine while seeking to position the newly selected music roll.
The revolver magazine is, of and by itself, a heavy piece of complicated looking machinery housed and anchored in its own centrally located cabinet space down below the “keybed” area of the piano. It is completely independent of all other player system mechanisms, except for three simple interconnections: (1) The leather belt that rotates the revolver magazine, (2) the metal rod that pushes down on the locking hook that locks the revolver magazine into position when the Play mode is initiated, and (3) the little spur gear that meshes with the large diameter gear on a take-up spool. Curiously, it is possibly the only contemporary coin piano whereby the roll mechanism can be disconnected from a mechanical power source and still happily carry out rewinding the music roll unattended.
However, before going further, it need be mentioned that the revolver magazines normally encountered can usually be divided into two easily recognized sub-categories (although minor variations using some evolutionary combination of both categories might exist): However, confusing the issue, two other variations of significance have recently been reported, one of them having a spring-barrel with a fan type governor for the rewind system, but no solid details are currently available. What follows accounts for those rewind system variations for which photographic evidence and verifiable details are available.
The spring-barrel motor type rewind system is comparatively rare and is thought to be a fairly early and relatively short-lived design, while the later coiled torsion spring system is quite common in surviving National coin pianos. For the spring-barrel powered rewind system the actual flat spring is safely housed in a geared brass barrel that is mounted with its axis of rotation in line with that of the music roll feed spool, although the two are only indirectly connected by means of intermediary gears. The feed spool is not removable, nor is the take-up spool, unless the revolver magazine is purposely disassembled. On the shaft holding the intermediary gears is a coarse square thread on which rides a cast bronze feed spool follower. When the music roll is being played the follower moves to the left, crawling longitudinally along the threaded shaft, but when the music roll is being rewound the spool follower moves back toward the right side of the revolver magazine. There is a stiff compression spring loaded plunger built into the spool follower that, when the plunger face pushed against a brake lever mounted on the outside surface of the roll station side plate, the take-up spool is immediately decelerated and then stopped, terminating the rewind process.
Inasmuch as the feed spool for the spring-barrel type of rewind system is not designed to be removed, this design suffers by making it challenging to change music rolls. To change a music roll—a quick and simple thing to do in most coin pianos—the old music roll must first be manually unspooled from the feed spool, and then the tabbed tail end of a new music roll must be inserted into a thin slot on the feed spool, and finally the new roll must be hand spooled onto the then empty feed spool. This meant that National music rolls had to be double ended, i.e., each end of the music roll had leader paper with a tapered end and a centered paper tab. Fortunately, when the feed spool is in its fully rewound and stopped position, the task of putting on new music is ameliorated by pushing the feed spool to the left, which disengages the feed spool from the intermediary gearing, allowing the feed spool to rotate freely. Moreover, by placing a flat shim (with a slot to accommodate the feed spool shaft) of sufficient thickness between the feed spool gear and the carrier side plate, the shim can mechanically hold the feed spool in the left disengaged position, freeing the hands to manually spin the feed spool to load the new music roll. This would make it relatively easy to unspool an old music roll and then spool up the new one with a minimum of effort. It is easy to imagine up some sort of accessory kit to facilitate changing music, and National may have provided such a kit, but no such apparatus has yet to be reported.
The late coiled torsion spring rewind system is the type most collectors are familiar with, and very likely the only National rewind methodology they have ever experienced—or heard about. The great advantage over the spring-barrel rewind system is that with the torsion spring method the music roll feed spool is interchangeable, and can be easily removed, and then replaced by a new already spooled music roll. This was probably a wonderful boon for route operators fed up with the cumbersome toil necessary for the advertised weekly change of music. The downside of the newer rewind system, if any, was that it was more complicated. Both the feed spool and the take-up spool had their own independent spool follower and braking mechanism, which needed to be reasonably well synchronized to simultaneously play their part in terminating the rewind phase. Moreover, the coiled torsion springs did not always age well (compared to the more durable flat springs used for the spring-barrel mechanism), eventually losing enough strength to cause incomplete rewind of music rolls. It is common practice today to replace the torsion springs when restoring a National piano.
The revolver magazine is characterized by the eight independent music roll stations (referred to as carriers in early National Patents) that are equally spaced around the outer circumference of its two side plates. Each of the individual stations is self-contained, with its own music roll feed spool, a take-up spool, and a spring-motor based rewind mechanism equipped with the necessary gearing and braking to safely rewind a music roll, and do so in such a way that the rewound roll is ready to be played over and over again. When the player system is switched into the Play mode, and the tracker bar is lowered onto the music roll, a small spur gear meshes with the large diameter gear on the take-up spool, pulling the music roll paper forward under the tracker bar. As the paper advances from the music roll onto the take-up spool, the rewind system spring-motor geared to the music roll feed spool is slowly wound ever tighter. It is this spring-motor that will be used to power the roll rewinding phase. Then, at the end of the music roll, when the tracker bar is raised and the spur gear meshing with the take-up spool gear disengages, the music roll is suddenly free to instantly begin its speedy rewind phase, eventually stopping short and leaving a few layers of music roll leader wrapped around the take-up spool, ready for the roll to be played once again.
There are at least two distinct types of spring powered rewind system employed by National, and rumor has it that there are more. Nevertheless, of the two documented methodologies—the early spring-barrel powered and the late exposed torsion spring powered types—both have been extensively studied and the principles of operation are well understood. However, each rewind system is quite different when it comes to exchanging music rolls, replacing old music for new tunes. The differences and a suggested method for dealing with them are detailed in the following paragraphs:
Each of the eight roll stations is equipped with both a music roll feed spool and a take-up spool, both of which are non-removable. Thus, music rolls cannot be easily exchanged in the quick and easy fashion normal for most rewind type coin pianos, which is to lift out the old roll with its own individual spool, and merely pop in a new already spooled roll. And so how does someone change music rolls when the spools are permanently fixed and cannot be removed short of disassembling the revolver magazine? There are a couple of ways that come to mind, neither as ominous as might be imagined, with the former requiring no special tools or equipment, while the latter needs one simple tool that almost anyone could rather easily fashion.
The suggested first method comes from Dick Hack, a professional restorer of things relating to mechanical music. His idea is presented below in eight simple steps:
Once this technique for changing music rolls is commenced is it critical to understand that the feed spool must never be let go to run free and “rewind” itself with no roll paper attached to the feed spool. Failure to heed this requirement will definitely complicate the roll changing process, and will require the new music roll to be tediously wound onto the feed spool by hand.
The other method requires the use of a simple tool, consisting of a flat spacer (or shim) a few inches long and with a short slot in one end. This spacing shim needs to be wide enough (3/4” overall width should be more than sufficient) so that the slot can slide over the right carrier plate bearing pin on which the feed spool rides. The thickness of the shim need be sufficient so that when it is slipped between the carrier side plate and the little gear on the feed spool, the spool will be shifted to the left enough to keep the rewind gear disengaged. And so, with your spacer shim tool in hand, follow these ten steps:
While the above roll replacement methods are perhaps not convenient, they are not so arduous as to be avoided. It may well be that National offered some sort of roll changing accessory kit to aid in the weekly job of unspooling and then respooling the feed spool, replacing the old music with new tunes. However, no such accessory device has yet to be reported. Moreover, National actively encouraged route operators to simply destroy old music rolls, and only keep fresh new music on hand, no doubt to maximize the profitable flow of nickels. As such, the built-in inconvenience of the spring-barrel rewind system, namely the imposed difficulty of salvaging old music rolls, probably did not matter much to the company, and the difficulties might even have been purposely sanctioned, so as to expedite the immediate trashing of old rolls the moment they were removed from a piano. Whatever the case, the company policy of destroying used rolls is surly a contributing factor for the rarity of early National music rolls.
It is important to understand that for each of the eight music roll stations on the revolver magazine there are two separate spool followers, one for the feed spool and yet another for the take-up spool, each mechanically independent of the other. The sole purpose of a spool follower is to keep track of (from a predetermined starting point) the number of spool rotations made while the music plays, and then, once rewind is initiated, to count backwards and precisely decelerate and then stop the movement of its associated spool the moment it reaches the starting point. Thus, when the rewind process is halted, there should be several wraps of music roll leader paper still safely wound around the take-up spool, with only roll leader paper exposed between the feed and take-up spools—all perforated paper should be fully wound back onto the music roll feed spool.
If a music roll was correctly loaded onto the revolver magazine (with both spools synchronized with their respective spool followers, when it is eventually removed the two spool followers will each be similarly seated at their own stop position. What is a stop position? This is the exact position on a threaded rod (geared to a spool’s axis) where a spool follower normally brakes the spool, stopping the rewind process. This occurs when the spool follower bumps up against a stiff compression spring that serves as a stop bumper. During play, the feed spool follower essentially counts the number of rotations of the music roll feed spool, beginning from the stop bumper starting point. Likewise, the take-up spool follower also counts the number of rotations of the take-up spool, but using a 4-to-1 gear ratio, which means that the take-up spool follower moves along its threaded shaft much more quickly than does the slower feed spool follower. This increased speed basically amplifies the accuracy and reaction time during rewind when the take-up spool follower comes up against the stop bumper spring.
When a music roll is finished playing and the tracker bar frame is lifted, the music roll will immediately commence rewinding, with the paper accumulating on the music roll spool tugging against a light braking action provided by a friction pad riding on the left side hub of the take-up spool. This light tensioning of the paper will prevent the paper from looping and help keep it snugly wound on the music roll feed spool. Now it is the job of the two spool followers to stop the two spools from spinning precisely when the roll paper reaches the stop bumper starting point. And, as should be obvious, it is imperative that the two spool followers be synchronized properly so that they, more or less, brake the feed and take-up spools simultaneously. However, being that the take-up spool follower moves some four times more quickly it will tend to take precedence and apply a more accurately timed and greater stopping force at the end of the rewind process, which suggests that accurately synchronizing the music roll with the take-up spool follower is probably a bit more important that it is with the feed spool follower.
Whenever you remove or insert a music roll into the revolver magazine you will need to disengage the gearing for the take-up spool follower. But where is the so-called release lever for the take-up spool follower? Facing the revolver magazine, on the outer left-hand side of each roll station is a long brass lever toward the back of the station. It is parallel with the metal side plate. This lever pivots toward the lower end and extends upward to rest against a shaft that runs behind the take-up spool. When the upper end of the lever is pushed to the right it disengages the spur gears (located on the opposite side of the revolver magazine) for the take-up spool follower. This allows the take-up spool to be rotated freely one way or the other without affecting the position of the take-up spool follower.
To remove a music roll, follow these four simple steps:
Once the music roll is removed the spool follower for the feed spool will be automatically and correctly set against its stop bumper. This possible reset will occur because of the torsion spring that powers the feed spool during the rewind process, which will try to “rewind” the drive chuck to its full stop position once the music roll has been removed. However, be aware that the take-up spool will not try to “reset” itself against its stop bumper. Consequently, it may be prudent to make certain that the take-up spool follower is properly seated against its stop bumper. To do this, turn the take-up spool gently in the rewind direction until a braking force can be felt. Keep in mind that there is a friction pad that rides on the off-side take-up spool hub, whose purpose is to apply a slight but constant tension on the roll paper during the rewind process to keep the paper snuggly wound onto the feed spool. Thus, when turning the take-up spool you will need to be aware of this light but constant braking effect, and be watchful of an abrupt increase in braking force due to the take-up spool follower coming up against its stop bumper.
To load a new music roll, follow these six simple steps:
During normal operation, there should always be several wraps of leader paper remaining on the take-up spool when the rewind phase terminates. The excess leader paper helps to compensate for any spool follower tracking inaccuracies and/or rewind overshoot due to momentum. However, if no or too little paper is wrapped around the take-up spool (when inserting a new music roll) the rewind process will likely decelerate too late, probably about the time the roll tears loose from the take-up spool. The goal here is to end up with multiple wraps of leader paper still on the take-up spool when the rewind brakes are applied, which is when both spools come to their “at rest” stopped position.
There are two fundamentally different types of vacuum pump that has been observed in National automatic pianos—the reciprocating type and the rotary type. Because the sampling at this point is still statistically almost insignificant, it is unknown whether another type of pump might have been used. Complicating our studies, photographs of extant instruments usually omit showing the interior of the pump or motor compartments. Moreover, the majority of the serial numbers recorded in the database study are in the 7,000 range, with a but a slim few in the 3-digit range, leaving us to wonder about the construction characteristics of the earliest National automatic pianos, circa 1909 and how they might have evolved onward toward the 1920s.
One of the oddities of all known National automatic pianos, unlike most other coin piano brands, is the total lack of a vacuum reservoir, which normally would also include a spill valve to regulate and keep constant the vacuum level throughout the entire player system. (Nelson-Wiggen was the only other major brand that normally had no vacuum reservoir.) The vacuum pump in National coin pianos is connected directly to the stack, which, in turn, provides a vacuum source for a vacuum regulation valve, which must not only maintain a fairly constant vacuum level, but that additionally controls the piano expression, the exact setup depending upon the type of stack installed.
What is believed to be the earliest National vacuum pump observed to date is what we have arbitrarily termed a wood frame reciprocating pump. This is because it has a four-throw crankshaft, with individual connecting rods that attach to bearing cleats fastened to each of four bellows situated on the pump framework below the crankshaft, a layout reminiscent of how a multi-cylinder reciprocating automobile engine might be constructed.
The pump consists of a strong wooden rectangular framework with four vacuum bellows mounted on the bottom floor of the framework. There are two pairs of bellows arranged side-by-side, with the two pairs facing each other. On the outer edge of each movable bellows board there is a die-cast cleat, to which a die-cast connecting rod is connected by means of a bearing shaft going though the flanges of the cleat. The uppermost horizontal part of the framework supports a 4-throw crankshaft, and to connect each of the four bellows (located on the bottom floor of the framework) there are individual die-cast connecting rods with a matching bearing cap for the crankshaft end. This type of pump is usually associated with a sheet metal drive pulley on its rear-facing side, and the usual metal chain sprocket on its front-facing side.
Two distinct sheet metal pulley variations have been noted, one with circular reinforcement around the hub and the more commonly observed type with ribbed reinforcement radiating outward between the hub and the outer rim. Wooden drive pulleys have also been noted on the reciprocating type pumps, but they may or may not have been original to the pump. The reciprocating pump also made use of a belt idler to help keep the belt tension constant, and that was fastened to the outside of the pump framework near the bottom floor. Overall, the reciprocating type pump is well-built, but probably more difficult to maintain and repair than would be what is thought to be a later and relatively simple rotary style unit with a single crankshaft throw and bearing.
What is thought to be the latest of the National pump types is what we have termed the aluminum frame rotary box pump. It basically utilizes the same box-frame and central single-throw crank idea that many other coin piano manufacturers used throughout the 1920s. It is an efficient design and is easy to maintain in good repair.
A slightly modified version of the National rotary pump used in its coin pianos—one that had a wooden platform mounted on its top to accommodate an electric motor—was used as the vacuum source for the National built Welte pipe organ roll changer mechanisms. These tall and elaborate roll changers had 10 music roll stations attached to a long endless chain that wrapped around hefty chain sprockets located at the bottom and top of a steel framework. These impressively constructed pipe organ roll changers were housed in a special cabinet, or built into a convenient closet.
A similar rotary pump, with some relatively minor modifications to the basic cast aluminum framework design, was later used in Auto-typist roll-operated duplicating typewriter machines. The Auto-typist was reportedly introduced in 1927, and commercially manufactured in the 1930s by the M. Schultz Piano Company, and then later by the American Automatic Typewriter Company, both Chicago, Illinois, based enterprises. The Auto-typist basically consisted of two machines. A perforator with a hole spacing of 5 per inch was used to punch an 11-1/4” wide paper roll. The paper roll was then transferred to and deciphered by another machine that was housed in a special typewriter desk, which controlled the keys of a standard typewriter through a system of vacuum powered control valves, pneumatic bellows, and a maze of interconnecting tubing alongside various other mechanical linkages. It was used by letter duplicating services, which created mass-produced “hand-typed” letters for businesses that wanted their mailings to appear to be personalized. The most elaborate models had a console with a selector device, based on the Western Electric “Selectra” patent (which Otto Schulz purchased at Western Electric Piano Company’s bankruptcy sale). The master roll included a number of boilerplate paragraphs; the “Selectra” fast-forward and rewind were used for printing these paragraphs in a specified sequence. Larger setups had a master console containing the roll and selector mechanisms, connected to a group of typewriters, each having a pneumatic stack that pulled its keys down.
The National rotary pump, however, is visually quite different than the rotary type pumps used in most American built coin pianos. It makes use of a hollow aluminum framework (instead of the common wood framework), which is both structural and it channels the vacuum generated by each of the four bellows. Small mounting feet protrude from each side of the aluminum casting at its bottom edge. Attached to the rugged exterior framework, at its vertical mid-point on both the front and back sides, is a horizontal aluminum cross member with bronze bearings to support the single throw crankshaft. The cast metal housing surrounding the crank bearing has four flanges protruding outward from it. To each of these flanges is attached (by means of two heavy duty machine screws) a length of rubberized canvas belting, which is, in turn, fastened by wood screws to a wood block mounted about midway on the movable board for each of the four bellows.
These flexible “connecting straps” eliminate the need for the four die-cast connecting rods with lubricated end bearings, which are necessary with the earlier wood frame reciprocating style pump. They also have the advantage that as long as the very durable rubberized canvas material remains flexible, they will never knock like most wood or metal connecting rods eventually end up doing. Although the rotary style pumps have been seen with a sheet metal drive pulley, the rotary pumps are usually observed with a wooden drive pulley on its rear-facing side, and the normal metal chain sprocket on its forward-facing side. It is likely that the rotary pumps used in National pianos are an adaptation of an off-the-shelf pump offered by some unidentified supplier.
The coin switch mechanism could be said to include a compendium of closely related items, all of which need do their part effectively for the coin handling process to function as intended. It is, however, the complicated looking mechanisms housed in the coin switch enclosure that usually grabs most, if not all the attention. Here, however, we will deal with the entire coin handling system, from top to bottom, which can logically be divided into three main interrelated and functionally diverse components. One perhaps ancillary item has been added to the lot, and that is the device that indicates which tune is currently playing. The following enumeration highlights the generalized properties of each logical division:
The coin slot faceplate is an artfully designed and crafted casting, with a series of clever coin-handling mechanisms mounted firmly on its backside. At the front side top are eight different coin slots, with a push button directly below each of the eight slots. Below the row of buttons is the cast inscription: “Play Nickel in One or More Slots; Push Button Each Nickel.” Further below is a display window that lists, by number, each of the eight tunes available for play. Above the tune display window is a simple key-lock used to gain access to the tune cards inside the display window.
Each coin slot, numbered 1 through 8, correspond to a specific music roll loaded onto the revolver magazine. The slots are accurately sized to accommodate only the coin denomination to be accepted, usually a U.S. 5-cent nickel. Any coins that are too thick or that have a diameter greater than the required coin size will not fit into the slot, and so are rejected outright without further ado. However, coins inserted that are too small in diameter will simply fall into the slot’s coin trap and be rejected as under-sized, and then further drop unceremoniously into the coin return tray where the customer can easily recover any rejected coins.
When a coin is dropped into a slot, it rolls through a short zig-zag chute and into a slotted die-cast coin trap—there is a separate, independent trap for each coin slot. At the bottom of each slot (in the coin trap die-casting) there is a spring loaded blunt ended lever, which blocks just enough of the slot to catch and prevent a properly sized coin diameter from falling through the slot. However, any coin smaller than the required coin diameter will fall freely through the trap and be guided by a metal chute to ring a small bell on its way into the coin return tray. To dispense a correctly sized coin still held in the coin trap—so that it can fall into and trip the coin switch mechanism—the push-button below the coin slot must be pushed fully inward to its stopping point. When this is done, the button pushes against a lever arm attached to the corresponding coin trap, causing the trap to swing back away from the coin slot faceplate and over the appropriate chute in the wooden multi-slot connector block below it. When the coin trap moves over the connector chute a dog on the blunt lever that retains the coin within the trap bumps up against a fixed metal bar. On contact with the bar, the blunt lever arm keeping the coin in the coin trap swivels downward, thereby exposing the full width of the slot and releasing the coin. It is important to understand that the coin trap must be moved back away from the faceplate casting until it is directly over the appropriate chute in the multi-slot connector block, and reach this position before the coin is released from the coin trap, otherwise the coin would end up in the coin return tray.
The coin trip mechanism does not function like other contemporary combination coin switch and play accumulator mechanisms, such as commonly used in many single-slot setups. Some of these single-slot mechanisms can accumulate up to 20 or so plays, and do this quite independently of what the player system might be doing. But in National coin pianos the coin switch mechanism is highly integrated with the player system, in fact guiding certain crucial operations, like determining when the revolver magazine is correctly positioned and then triggering the player system into the Play mode. These are not functions normally associated with a single-slot coin switch accumulator.
For the National piano coin switch device, only one coin per slot deposited during any one Play mode cycle will be acknowledged, i.e., once the player system is put into Play mode, multiple coins dropped into any one slot will only count as a single coin. This rule of thumb does not, however, perfectly apply when the player system is powered off and the first coin is dropped, causing the player system to be powered up. This is because when the electric motor initially starts up the player system will be in the Rewind/Roll Changing mode, not the Play mode. It is when the system switches to the Play mode that the trip lever for the currently playing tune is reset. This is done when a stud on the studded selector cylinder in the coin switch mechanism engages a tripped cam lever, setting in motion these actions: (1) the player system is triggered into Play mode, and (2) the coin trip lever for the selection being played is reset. Once this reset action for the currently selected tune occurs, another coin can be dropped into the same slot and it will register, allowing the same tune to eventually replay, although if other tunes have also been selected during the current Play mode the system will cycle through and play them in succession.
Made of many carefully cut and fitted together bits and pieces of wood, this multi-slot and gracefully contoured connector delivers coins from the upper and much wider coin slot faceplate unit to the lower and much narrower lineup of coin chutes down in the coin switch mechanism. The transfer connector sits below and to the rear of the row of individual coin traps located on the backside of the coin slot faceplate. It is only when a coin slot push-button is pressed that the corresponding coin trap is moved rearward, so that it is rightly lined up over the waiting connector chute below it, otherwise the coin would miss the opening in the transfer connector. To alleviate any minor alignment issues, the topside wooden chute entry openings are wide and spacious, with the upper ends of the wood separators tapered to a point. This wide-open spaciousness allows the individual wooden chutes enough leeway to reliably catch and collect coins dropped from the coin trap directly above. On the bottom end of the connector, the woodwork fits snugly above the multi-chute die-casting located at the back of the coin switch mechanism.
The National coin switch mechanism, with its eight separate coin slot layout, is unique amongst all of its competitors, all of which utilized a much simpler single coin slot design, which in many cases used standard off-the-shelf components. But not National. The company choose a very different, independent methodology. Nonetheless, both the National way and the somewhat standardized industry wide coin processing methods proved to be durable, and could usually be counted on for many years of mostly trouble-free service. And so, within its enclosure, the National style coin switch mechanism, although perhaps complicated looking, can logically be divided into three functionally unique but interconnected sections. These are enumerated below, going from front to back:
What follows next is a brief and simplified description of how the coin switch mechanism works:
When a coin falls through one of the eight coin chutes (located at the back of the coin switch mechanism) it impinges upon a trigger pawl near the bottom of the chute. When this happens a vertically oriented extension on the trigger pawl rotates toward the rear, which then allows the end of a lever arm resting on top of the pawl extension to slip free and drop. The other end of this lever arm is enlarged and rounded where it swivels around its pivot point, Below the pivot point is a tension spring that works to rotate the lever's trip arm downward, while above the pivot point there is a short projection sticking up that is forced in a rearward direction. This projection has two functions. Firstly, it is drilled with a hole to accept a long hooked wire that connects with corresponding linkage that interacts with the studded selector cylinder in the middle of the coin switch enclosure. When this wire is pulled it causes a finger to pop forward toward the studded cylinder, putting it in the path of one of the cylinder studs. Secondly, as the upward sticking projection is rotated to the rear it pushes against a suspended metal bar that is free to swing to and fro (within limits). This bar runs the entire width of the coin switch enclosure, so that any coin chute pawl that has been tripped will cause an affected lever arm to impact this swinging metal bar, pushing it toward the rear of the enclosure. When it is pushed back it comes up against a vertical lever that, in turn, trips the electrical switch at the front of the enclosure, which then makes electrical contact. If this metal bar is kept in the rearward position, such as when multiple tunes have been selected, the coin switch will not open (break the electrical circuit) until all of the coin trip levers have been reset, one by one, as any additionally selected music rolls have been played.
Moving on to the center of the enclosure, is the studded selector cylinder and associated linkages. When one of the wires connected to a coin trip lever pulls the corresponding linkage associated with the studded cylinder, a metal finger is caused to move closer to the studded cylinder (each finger is akin to a vertical lever with a projecting tip or finger at the top end that is facing toward the cylinder). With the finger moved closer to the cylinder surface, when the corresponding stud on the rotating cylinder touches the finger it will be pushed downward, and at some point, after sufficient travel distance, it will be disengaged from the stud. When any finger is pushed downward it both resets the corresponding coin trip lever, and it presses down against a heavy-duty metal bar attached at both ends to a steel shaft, which has a simple lever arm on its front facing right end. When this shaft is rotated (perhaps a quarter revolution) a wire linkage between it and a cast bronze bell-crank (near the front of the coin switch enclosure) twists the small inner shaft traversing the front of the “keybed” area. Momentarily rotating this long inner shaft triggers the Rewind/Play mode clutch to cycle the camshaft into the Play mode position. When multiple tunes have been selected, the corresponding fingers next to the studded selector cylinder will be moved closer, so that when the current music roll trips the rewind pallet, and the player system goes into the Rewind/Roll Changing mode, the studded cylinder will again rotate and a different stud will push down the next successive finger to be encountered. This process will repeat until all the selected tunes have been played through and any associated coin trip levers have been reset, whereupon the electric switch contacts will finally be pulled open, shutting down the player system.
Lastly, at the front of the coin switch enclosure, is the insulated electrical switch block, and in front of it the operational linkages that control the knife switch action. This insulated block uses copper strips to connect the electrical wiring terminals to the two fixed switch blade contacts. The knife blade itself is electrically neutral, and is connected to but electrically insulated from the steel lever arm that raises and lowers the switch blade. When the player system is off the knife switch blade is raised, breaking the electrical circuit, and it is kept latched in that upward raised position until specifically released. When a coin falls through one of the coin chutes at the back end of the coin switch enclosure, and trips a coin trip lever, the vertical oriented latching lever (at the front of the enclosure but connected by a long metal rod to the coin trip mechanism) is pushed forward. This action forces the latching lever to swivel slightly, which releases the latch pin projecting outward from the knife blade lever arm, allowing the electrical contacts to close. Cleverly, the bearing pin, on which the latching lever swivels, is attached to a horizontal lever that can be raised and lowered by a bell-crank, which is clamped onto the larger hollow shaft that traverses the front of the “keybed” area, and that is further attached to the cam follower lever for the “coin switch reset cam.” When the vertical latching lever is raised, by the action of the reset cam, the latch pin on the switch blade arm can re-engage. Then, when the vertical latching lever is lowered, it pushes down on the latch pin located on the forward end of the knife switch arm, in turn swiveling the knife switch on the opposite end of the lever arm into the open position, breaking the electrical circuit. However, when several tunes have been selected the rod controlled by the coin chute trip levers will keep the vertical latching lever pushed forward. This will prevent the latch pin on the knife blade lever arm from re-engaging the vertical latching lever, until all selected tunes have been successively played and their associated coin trip levers have been reset, whereupon the player system will then be shut down.
The coin collection box is located underneath the "keybed" area shelf and on the right-hand side of the piano case. It and the electric motor share the same compartment. Directly above the black painted coin box is a sheet metal coin collection chute that funnels any coins passing through the coin switch mechanism into the large and lockable steel coin collector box. Inside the top of the metal box are a pair of brackets that are used to hold a stiffened hoop sewn into the top edge of a suspended cloth bag used for the collection of coins, and that can be quickly pulled out and replaced with an empty bag. This makes transporting the day’s receipts both quick and easy.
Retrieving the coin piano receipts may seem to be a trivial occurrence, but I am reminded of a story told to me in the late 1960s by the late Jim DeRoin. Jim had some number of coin pianos out on location in the San Francisco and Oakland areas. One day he was down on his hands and knees collecting coins from the bottom of a piano when he felt a strange tickling sensation across his throat. Puzzled, he looked up only to see a man standing over him with a switchblade knife, having just attempted to slit his throat, but not cutting deep enough to do major damage. Jim, a strong and burly fellow by nature, grabbed a piano stool next to him and broke it over the guy’s head, which, needless to say, aborted the attempted coin piano robbery.
All known National coin pianos have, or at one time had, a tune indicator wheel attached to and located in the upper left-hand side of the piano case. The rotational position of the tune indicator wheel must be perfectly synchronized with the angular position of the revolver magazine, so that the tune number being displayed always exactly coincides with the music roll positioned under the tracker bar. To accomplish this end, a chain around the sprocket on the backside of the tune wheel connects with a similar sprocket underneath the “keybed” area shelf. This lower sprocket is fixed to one end of a countershaft that extends over to the left side of the revolver magazine, where another length of chain and set of chain sprockets connect the countershaft to the revolver magazine. Because all the linkages are chain, there is no slippage resulting in misalignment between the tune wheel and the revolver magazine. However, although functionally identical, two different types of underlying support construction have been observed, as follows:
The underlying support structure provides (1) a bearing surface on which the numbered tune indicator wheel can revolve, and (2) a mounting platform for a small pneumatic that raises and lowers a metal shield to cover over and conceal the otherwise exposed tune number whenever the player system is powered off. The tune indicator wheel itself is nothing more than a thin sheet metal disk with eight large equidistant holes punched a little inside its outer circumference. In the center of the disk is a small metal hub, to which is attached a short shaft on which the tune indicator wheel rotates, and at its outer end is a small chain sprocket used to synchronize the tune wheel to the revolver magazine. The front surface of the metal disk is painted black. On the backside of this disk is a pre-cut paper circle, with large numbers (1 through 8) printed inside its circumference, which has been pasted onto the backside of the tune wheel. From the front side, the circle of individually printed large numbers show through the large diameter holes punched in the metal disk.
The selected tune number is made all the more apparent by an electric light hanging near the backside of the tune indicator wheel, which illuminates the printed numbers from behind. This electric lamp is located a little above the tune indicator wheel, but yet effectively spaced between it and the piano action, which, when the player system is powered on, illuminates the entire upper interior of the piano. When the case front is in place the tune indicator device is hidden, except for what can be seen through a circular aperture in the case front, which is precisely positioned to be in front of the number representing the currently selected tune. When the player system is powered off a metal shield drops down and covers the otherwise displayed number, but when the player system is powered on the electric light behind the tune indicator wheel is brightly lit and the protective metal shield is lifted out of the way by a small pneumatic connected into the stack vacuum supply. This action allows the number for the currently playing tune to shine brightly through the case opening, announcing to all the number of the currently playing musical selection.
For National coin pianos, the electric motor of choice seems to have been a Holtzer-Cabot motor. Thus, having the motor nameplate information can be very helpful in sometimes approximating the manufacturing date of National automatic pianos. This is because original Holtzer-Cabot factory information survives that makes it relatively easy to determine what year the motor was manufactured. Of course, there will be some delay between the manufacturing date and when the motor was eventually installed in a National piano, but so far using the motor to estimate the piano manufactured or shipping date is about the only tool currently on hand that has a reasonable chance of being useful. This situation may change as more pianos are added to the National coin piano database, perhaps providing more clues once the mechanical evolution of the pianos can be more accurately studied and compared.
It should be understood that using the motor as a piano dating guide has its shortcomings. For instance, a troubled motor in a piano bringing in money from a lucrative location might have hastily been swapped out with the motor in an idle piano sitting in storage, or when a piano was refurbished and/or retrofitted with a dog race diorama or “dancing figure” trade stimulator a fresh new motor might have been installed. Or maybe a motor was temporarily “lost” in a secluded nook in a distributor’s storage warehouse, and then when eventually discovered this “old” motor was sold and later inserted into a new National piano, which would cause the motor date to be much earlier than the piano date. Moreover, anyone with a good imagination could come up with a myriad of other scenarios that would upset any scheme using a motor to determine when a piano was factory made or shipped.
To determine the approximate manufacturing date for a Holtzer-Cabot motor please refer to the Dating Holtzer-Cabot Motors section on the Electric Motors in Coin Pianos page.
The Automatic Whippet Race (alternately known, in lieu of its true name, as a Dog Race Diorama) was a popular trade stimulator retrofitted by National in a last heroic but vain attempt to extend the commercial viability of the company’s ever-growing stock of idle coin pianos. The diorama’s mechanisms are both intricate and beautifully constructed, but that effort did little to prolong the coin piano business, which faced ever more aggressive competition from radio, the automatic phonograph, and talking pictures, all entertainment venues finding enormous popularity with the public sector. The hand-writing was clearly on the wall, and even National (reorganized as AMI in 1925) itself recognized this, and had been busy developing its own version of the automatic phonograph—The National Selective Phonograph, Introduced in 1927.
The whippet race diorama, and all of its many parts, contribute to what amounts to a substantial piece of ancillary equipment. It is bulky, it makes use of mechanical sub-assemblies, it has its own pneumatic valve chest for control and certain randomizing functions, and it requires a steel framework in which to contain and hold the various components. Consequently, it is weighty. Moreover, the external Geneva gear-driven randomizer module needs it own source of motive power, as does the input shaft for the whippet race mechanism itself. To accommodate this additional need for rotational motive power, more chains, sprockets, and countershafts were added to the already existing maze of gears, sprockets, and drive shafts. Unfortunately, for pianos with the retrofitted diorama, it became much more difficult to tune the piano or work on anything requiring access to the stack or associated mechanisms.
The most obvious feature of the race diorama is the colorful artwork background, as well as the four Whippets, either waiting impatiently to begin a new race, or perhaps they are randomly spaced along the raceway after finishing a race, still waiting to be reset, and made ready for the next event. When a Whippet’s nose touches the finish gate the race is over, and the underlying mechanism that moves the hounds is instantly disengaged—forever, unless someone intervenes and manually resets the race mechanism. On the front of the piano case, and to the lower right of the race diorama window, is a control lever with a Reset position to the left, neutral in the middle, and with a Race position on the right side. Starting a new race, or resetting a finished race, i.e., lining up the Whippets at the starting line, are manually initiated operations, and can only take place when the player system is powered on and rotational power is applied to the input shaft of the whippet race machinery.
There are two equally spaced Whippets mounted on each of the four endless thin spring-steel bands that move the hounds along the race track, with each band threading around a large diameter pulley at each end of the diorama’s short but pretty race track. The individual pulleys on the left side are merely idlers that maintain sufficient tension on the steel bands, while the pulleys on the right side do the work of pulling the hounds forward. For each band, only one Whippet is visible and on the race track at any given time; the other one being upside down and underneath the race track until it is moved into a starting position for the next race. Oddly enough, the real starting gate is a metal plate that stops the movement of the hidden Whippets underneath the race track, near the working pulleys. When the noses of all four upside down Whippets are touching the starting plate, the visible Whippets at the beginning of the race track will also be properly lined up and ready to go.
The four working pulleys (that move the Whippets) all ride, side-by-side, on the same gear driven shaft, i.e., they could spin freely on the shaft if it were not for the pair of unseen brake shoes opposite each other inside each pulley. These brake shoes are supported by a framework that is firmly attached to the drive shaft. Between the two shoes are compression springs, so that each brake surface exerts the same amount of resistance against the inner circumference of the pulley’s rim. The spring tension must be just sufficient to provide enough force so that the steel bands (to which the hounds are attached) will pull the Whippets unerringly forward, and yet, at the same time, easily and gracefully slip whenever the working pulley is intentionally or otherwise halted.
There are two normally occurring scenarios that necessarily halt the forward motion of the Whippets, but do so without stopping or interfering with the rotation of the drive shaft on which the four working pulleys ride. By default, a locking pawl is pushed into the toothed flange on the outer edge of the four working pulleys, which causes the brake shoes inside each of the locked pulleys to harmlessly slip, unless the locking pawl is released, during which interval of time a Whippet can race forward. As such, at the beginning of each race all four Whippets are halted, unable to move forward except when intermittently allowed to do so by the so-called randomizing system (consisting of several separate but interconnected components). Each Whippet will move forward in randomized spurts, with the outcome more or less unpredictable.
The other situation (when a Whippet must be halted) is when the whippet race mechanism is being manually reset, and the Whippets are moved forward until, one by one, each Whippet’s nose bumps up against the starting gate (located underneath the race track) and stops it dead in its tracks. Here, again, the brake shoes inside the working pulleys must slip, but this time because the associated Whippet is physically preventing from moving past the starting gate. Thus, no matter whether the Whippet is paused by locking the working pulley or by physically stopping the Whippet itself, the amount of braking applied, or perhaps alternately described as the amount of slip allowed, is a critical adjustment that must be set with care. The racing Whippets need to be reliably moved along when appropriate, but it is imperative that they be safely and gracefully stopped whenever a Whippet’s nose touches some kind of fixed barrier.
The mechanical mechanisms are generally easy to understand through casual visual inspection alone; the randomizing functions not so much. The valve chest and the four control pneumatics that link to the locking pawls for each of the four working pulleys are contained within the diorama underneath the race track. Two important associated but external components are connected by means of rubber tubing. The first of these is a row of fifteen spring metal pallet valves mounted on top of the stack cover. The free end of each spring metal strip rests over the end of a piano wippen, so that when the piano note is played, and the end of the wippen is pushed upward, the spring metal strip is raised slightly, opening a port otherwise sealed shut. Approximately every forth valve is teed together, resulting in just four rubber tubes that represent the combined output signals generated by the individual pallet valves. These four tubes are connected to the Geneva gear driven randomizer module mounted on the “keybed” area of the piano.
The piano notes used by the pallet valves are the top fifteen piano notes in the mid or tenor section of the piano. The idea here is that these selected piano notes will be played somewhat randomly, or at least differently, for each and every tune. Thus, the resulting signal for each of the four output tubes will be randomized through various combinations of pallet valves being “unpredictably” opened and closed as the music plays. But to further confuse, or randomize, the signals, the four output tubes are attached to the Geneva gear driven randomizer module.
The gear driven randomizing device gets its motive power from an added chain sprocket stuck onto the end of the tooth clutch shaft used to rotate the revolver magazine during the music roll selection cycle. The purpose of the randomizing module is to take the four channels of gibberish coming from the pallet valves and further randomize it, by further breaking up any repeating patterns. Fundamentally, music is not random, but follows very precise rules, although taking part of a melody and screwing up any obvious patterns is probably more than sufficient for the simple requirements of the whippet race mechanism.
The randomizing part of the module consists of two thick circular metal parts mounted on a common shaft, and with a common machined-flat mating surface between the two halves, with each half drilled and channeled with various air-tight passageways. The stationary half has four incoming rubber tube connections (from the pallet valves operated by the piano wippens), and four output connections that go to the valve chest in the diorama, which, in turn, operate the four pneumatics that serve to intermittently and randomly unlock the working pulleys. The rotating half of the randomizer moves in discreet steps, advanced one step at a time by the Geneva gear, followed by a pause, with each step connecting the input and output tubes differently, adding more unpredictability to the action of each individual racing Whippet. The upshot here is this: Each Whippet moves forward unpredictably in spurts, each effectively inching toward the finish gate at varying speeds, all according to the multi-level randomization of signals generated by the piano note operated pallet valves working in combination with the independent stepped Geneva gear driven randomizing module.
There are no currently intact National automatic pianos known that have been retrofitted with the so-called “Dancing Figure” amusement. But there are, however, some loose parts that purportedly make up the “Dancing Figure” apparatus, which are thought to have come from a junked out National piano with a Simplex style stack. The “Dancing Figure,” in this instance, consists of two main parts:
The head of the doll is dark-skinned in color and sits atop what appears to be a flexible, jointed body clothed in a simple but attractive Native American costume—other costume variations probably existed. The only mechanical attachment was the single wire encircling its neck (and then bent upward at a right angle), which, when yanked up and down, caused the doll to flop around and “dance” as it bobbed to and fro. There was nothing sophisticated about its movement or how it was controlled. To automatic and coordinate the doll’s action with the music, tracker bar hole #68 (normally C#, the uppermost playing note) was reportedly connected to a unit control valve, which was, in turn, connected to the overhead pneumatic that animated the “Dancing Figure.”
To accommodate this retrofit device, at least some of the late National rolls are said to have used perforation #68 to operate the “Dancing Figure” attachment, and hopefully keep its flailing antics somewhat in time with the music. Because tracker bar hole #68 was repurposed some restorers have reportedly disabled this tracker bar position for regular National pianos that do not have a “Dancing Figure” retrofit. Doing so prevents the uppermost playing note from sounding in odd and non-musical ways when playing late music rolls, which, if hole #68 was left connected, would upset the otherwise pleasant musical arrangement.
Because of the crudeness of what may be representative of the so-called "Dancing Figure" attachment it brings into question whether this was something actually sanctioned and installed by National, or was it something clumsily added, for instance, by some eager route operator trying to stimulate business? Or was the original dancing figure badly damaged or missing, and this crude substitute took the place of a figure much more fitting of the flapper era? This may be a question that is never satisfactorily answered. Anyone able to provide additional information about the "Dancing Figure" retrofit is invited to share their knowledge at:
This page contains detailed descriptions and photos of various features, which are deemed important for a truly useful understanding of both the database reports and to effectively fill in the Survey Reporting Form. The actual database reports and survey form can be accessed in the Distribution of Database Information section and then clicking on the large Download button at the bottom of this page.
The primary information that inspired the creation of the National Automatic Piano database was gathered by Andrew Barrett, a mechanical music enthusiast located in California. Many other people, listed under Acknowledgments in the Introduction to the Registry, have also contributed information, all of which is presented in an orderly, easy to read format on this web page and in the database report offered below.
By default, current ownership information is not integral to the database project, but a provision exists whereby the current owner's name information can be accommodated and then shown in database reports. However, this will be done only if and when specific written permission is granted to the Mechanical Music Press specifically authorizing us to show and/or distribute individual ownership information. Furthermore, if and when such authorization is granted the Mechanical Music Press and/or its authors shall assume no liability or responsibility of any kind, nor to any extent, regarding any inferred, purported, or actual privacy intrusions, incidents, or claims.
We cordially invite and solicit additional information for the database on National automatic pianos that are not in this list, and additional details for pianos that are already listed but that have little information.
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Q. David Bowers, Art Reblitz, Durrell Armstrong (deceased), John Perschbacher, Terry Hathaway, Dana Johnson, Dick Hack, Andrew Barrett, Bob Gilson, Jody Kravitz, and David Krall.
Dana Johnson, Dick Hack, David Anderson, Bob Gilson, Dan Zelinsky, David Krall, and Terry Hathaway.