Patent GB-230823-A (GB)
Title: Improvements in and relating to automatic musical instruments
Filed: 1925-03-09
Abstract: 230,823. American Piano Co., (Assignees of Stoddard, C. F.). March 12, 1924, [Convention date]. Expression-controlling; exhausting air. - In addition to a regulating valve which may be controlled to produce both incremental and crescendo and diminuendo changes in intensity, means are provided to regulate the main suction to varying degrees of intensity. The normal scale of intensities produced by the regulating valve is thus transferable proportionally to other main levels of intensity. The regulating valve 31, Fig. 1, controls the port 30 situated between the chest 14, connected at 15 to the pump 16, and the chest 12 connected at 7 to the playing action 1. The means shown for directly controlling the regulating valve 31 to produce the normal scale of intensities is stated in the Specification as open to inspection under Sect. 91 (3) (a) to be as described in U.S. Specification 1,409,492, and is referred to below. The means for producing different main levels of intensity comprises a spring-pressed valve 213, Fig. 2, admitting air to the suction chamber 202 of the pump 16, the air being withdrawn through a muffled passage 218 from the internal chamber 221a communicating with the atmosphere through holes 221. On the equalizer bellows 201 are mounted two bellows 230, 231 whose expansion is limited by stops adjustable by screws 238, 241. The outermost leaf 240 has a lug 232 for opening the valve 213 by engagement with a collar 233. When both bellows are collapsed the equalizer 201 will maintain the main suction at its weakest, and when both are expanded, at its strongest, intermediate degrees of intensity being obtained by collapse of one or other of the bellows 230, 231. The bellows 230, 231 are automatically controlled from tracker-bar apertures 276, 276a through a valveblock 250 connected at 256 to the suction chamber 202. Normally the bellows 231 is collapsed. Passage of a perforation at 276 opens a valve 270 to atmosphere, which by the connection 266 opens valve 251, thus connecting the bellows 231 to atmosphere to expand it. Passage of a perforation at 276a operates valves 270<a>, 252 to collapse bellows 230. Valve 270 or 270<a> may be caused to remain open after passage of a small perforation in the tune-sheet, by admission of air from the opened valve, as 270, to the diaphragm chamber 274 through a passage 277, 279 with bleed 278. To nullify this action and close the valve 270, the main cancel valve 84 described in U.S. Specification 1,409,492 is used, which valve is operated from the tracker-bar and admits air to the diaphragm 286 operating a valve 285 to close passage 277, 279. The valve 31 referred to above serves (i) for regulating intensity through its connection to the common pivoted board 33 of three regulating pneumatics 34, 35, 36 connected to the chamber 12; (ii) for effecting automatic incremental changes of intensity, tracker apertures T, T<a>, T<b> connecting any one or more of the pneumatics 34, 35, 36 to atmosphere by the operation of diaphragm-operated valves 58, 50. These valves may be kept open after the small perforation used in the tunesheet has passed, until nullified by the operation of a valve 92 by the cancel valve 84 referred to above; (iii) for producing either slow or rapid crescendo and diminuendo changes in intensity, by variation of the suction in a pneumatic 37, acting on the other side of the movable board 33 and connected to a larger pneumatic 101 which normally maintains its internal suction constant by means of a regulating valve 112 balanced between atmospheric and suction seatings. This valve 112, should the suction in the pneumatic 101 diminish owing to movement of the board 33, opens further to increase the suction admitted under the control of a screw 119 to the pipe 106, owing to expansion of the pneumatic 101 underthe influence of the adjustable spring 102, and consequent further lifting thereby of a valve 118 thus admitting more atmospheric air by a passage 117 to the underside of the diaphragm of the valve 112. More rapid adjustment is given by an extreme lifting of the valve 118, atmosphere then being admitted by a passage 133 to raise, a valve 129 and open a by-pass valve 123 which cuts out the more obstructive screw 119, the suction admitted to pipe 106 being then controlled only by a less obstruction screw 120. A slow crescendo is obtained either manually or, as shown, from a tracker-aperture R and duct 138, the valve 112 being lifted to a higher position and the additional suction past screw 119 gradually increasing the tension in pneumatics 101, 37, thus opening valve 31 wider. A slow diminuendo follows closing of the aperture R. Another tracker-duct is opened to operate the valves 129, 123 when the crescendo or diminuendo is to be rapid.