Inside the Wurlitzer Automatic Harp

(Photograph courtesy of an unknown source)

An interior view of the Wurlitzer Style B Automatic Harp. The mechanism in this example is of the early type, with wooden linkages to the string pluckers. A later mechanism used a string or cord in place of the wooden linkages, which reduced the level of mechanical noise and made adjusting the length of the linkage between the motor pneumatic and plucker mechanism much easier and quicker. The valve chest in the automatic harp used a set of unique conical shaped rubber valves, instead of the flat leather seated valves common throughout the rest of the coin-operated mechanical music industry.

(Photograph courtesy of Dick Hack)

Two examples of the unconventional valve stem used in the Wurlitzer Automatic Harp, the stem on the right viewed head on, while the one on the left is tilted back to show the bleed hole in the bottom eyelet. the large diameter area of the stem is hollow and vented to vacuum by means of the "vacuum vent hole" as captioned in the picture. Inserted into the hollow part of the valve stem is an eyelet, with a small bleed hole at its center. Between the eyelet and valve stem fragments of the original rubber cloth pouch are visible. This is because the eyelet goes through a hole in the pouch, which is then inserted into and glued to the valve stem. At top left is the conical shaped hard rubber valve, which slips over the small diameter projection sticking up from the top of the valve stem.

The order of assembly was (1) eyelet inserted into punched hole in pouch, (2) eyelet/pouch assembly inserted and glued into bottom part of valve stem, and (3) the eyelet/pouch/stem assembly was glued onto the pouch board. Then, (4) once all of the pouch assemblies were glued in place, the bottom or vacuum seat board was threaded over the valve stems and the board put into place. Then (5) the conical valves were slipped over the stems, and finally (6) the upper or atmosphere valve board was threaded over the stems and screwed onto the rim of the chest.

(Photograph courtesy of Dick Hack)

Bottom or vacuum seat board for the valve chest. The view shows the layout of the valves and the inserts that make up the valve seats. According to the handwritten notation scrawled inside the chest, this automatic harp was restored by "Louis Bacigalupi, Jr., Los Angeles, Calif., March 26, 1946."

(Photograph courtesy of Dick Hack)

Close-up of the valve seat wells and the valve seat inserts in the lower or vacuum seat board in the valve chest. The valve seats were glued in place at the time of insertion, and are described by Dick Hack, who has restored a number of Wurlitzer Automatic Harps, as being "like a grommet with a thin molded rubber ring that is very flexible," which enabled the insert to accurately seat to the conical valve. The valve travel distance was determined by the thickness of a cork like gasket sandwiched between the bottom and top (or atmospheric) board. This large gasket was punched to accommodate all of the valve wells and the hundred or so screws to hold the chest together.