Automatic Musical Company
Mandolin Emulating Attachment

(Photograph courtesy of Terry Barnes)

Overview of the Automatic Musical Company's unique mandolin attachment, a free standing mandolin emulating mechanism that was independent of the piano action and its strings. The unit, patented August 2, 1904, consisted of a mechanically operated set of 31 thin metal pluckers. each one, when activated, strumming one of 31 pairs of strings, the bass end being C sharp (key #41 on the piano keyboard) and up through G (key #71). The mandolin device had its own pinblock, soundboard, and plucker assembly mounted in an elaborate, well designed casting that was held in place by two sturdy brackets, so that the unit hung down in front of the mid-range portion of the piano. A small round-belt driven crankshaft provided the side-to-side oscillating motion for the individual pluckers. The individual pluckers were activated by wood stickers that rested in adjustable capstans screwed into the rear portion of the affected piano keys.

(Photograph courtesy of Terry Barnes)

Hanger bracket for the mandolin device, which is fastened to and extends outward from the piano plate. On the topside of the bracket is a block bearing supporting a bearing pin that projects outward from the mandolin device's main plate casting. This allows the mandolin pinblock and sounding board to swing to and fro in relations to the pluckers, which are suspended independently. At the front end of the bracket is a drilled hole and slot, into which is slid one end of a metal strap or hammock that supports the oscillating framework that holds the string pluckers. The ends of the metal strap are crimped over, and it is this crimped edge that slides into the bracket hole and that in turn keeps the metal strap from falling out of the bracket. Then by carefully positioning the metal strap slightly in or out in the bracket the position of the pluckers can be set very precisely in relation to the mandolin string pairs, and then the strap locked in place by a thumbscrew.

(Photograph courtesy of Terry Barnes)

Hammer rail soft pedal link to mandolin device. As alluded to earlier, the mandolin pinblock and sounding board plate casting hangs in such a way that it can swing to and fro in relation to the fixed but adjustable framework that holds the pluckers. But its ability to swing is constrained by a spring loaded adjustable knob arrangement. A coil spring keeps the a bottom flange on the cast iron mandolin plate up against an adjustable notched knob, which can be locked in place by inserting a machine screw through one of the notches and into the cast iron flange. This keeps the distance between the string pairs and the pluckers accurately adjusted. But notice the lever behind the knob that extends upward to the top side of the hammer rail. A thinner and more flexible adjustable metal strap extends from the lever to the topside of the hammer rail, and pivots around a regulating screw (whose round eyelet is visible). When the hammer rail moves forward the fulcrum point of the lever, which is at the upper edge of the gilded plate flange (just above the adjustable knob) causes the mandolin plate to move away from the pluckers ever so slightly, effectively softening the brilliance of the mandolin tones.

(Photograph courtesy of Terry Barnes)

Piano key adjustable capstans for adjusting the stickers for the mandolin device. These adjustable capstans can be rotated to precisely adjust the vertical length and actuating point for each of the 31 string pluckers. The springs insure that each vertical wood sticker stays aligned and retained within the slight depression on the topside of each capstan screw, and that the stickers and attached pluckers accurately drop back down and follow the action of the piano keys.

(Photograph courtesy of Terry Barnes)

Metal plucking tab in oscillating frame for the mandolin device. Each of the 31 metal pluckers is held within the framework by a common rod that runs through a hole toward the bottom of the pluckers. When the backside of a plucker is pushed upwards by a sticker it tilts forward and engages its string pair. Notice the simple looped wire connectors at the top of each sticker, which connect the stickers to there respective pluckers. The white colored piano rail felt bushings prevents metal to metal clatter due to the fast oscillating motion of the plucker framework.

(Photograph courtesy of Terry Barnes)

Right side view of plucking tab connectors for the mandolin device. This view clearly shows the two wires that project upward from the end of each wooden sticker. The wire on the left is looped with a tail that goes through a small hole in the plucker. The wire on the right merely keeps the looped wire with a tail from coming out of the connecting hole in the plucker. In the center of the picture and on the wooden framework that holds the string pluckers is the patent notice.

(Photograph courtesy of Terry Barnes)

Belt driven crankshaft that operates mandolin device's oscillating framework. This small round-belt driven single crank attachment, with its own flywheel, is what imparts the side-to-side oscillating motion to the mandolin device's pluckers. It is connected to the moveable framework by a simple wooden connecting rod. The unit is nestled between the piano case and bass end piano hamers.

(Photograph courtesy of Terry Barnes)

Belt driven manually operated pin type clutch arrangement for the mandolin device. This unit is mounted at the bottom of the piano near the motor. The large pulley is connected to the motor, which is fitted with a dual belt pulley, one belt connecting to the vacuum pump and the other to this mandolin attachment clutching device. The smaller pulley would be belted to the mandolin device's crankshaft pictured in the above image. Notice that the smaller pulley is free riding on the shaft, and is slid into an "on" or "off" position by a lever that is connected to control knob underneath the left side of the keybed, but easily accessible to anyone who knows of its location. Thus, the mandolin attachment could be engaged or disengaged at whim. At the upper right of the picture is the bottom of the receiving coin box--holding the day's receipts.