Patent GB-190211558-A (GB)
Title: Improved Playing Attachment for Musical Instruments.
Inventor: BIRKBECK HENRY
Filed: 1902-05-21
Granted: 1902-08-07
Abstract: 11,558. Birkbeck, H., [Ludwig, J. H., and Ericsson, C. A.]. May 21. Automatic instruments.-Relates to a pneumatic apparatus for playing keyboard instruments. The motive power is obtained from compressed air supplied through a pipe 146, with a branch 149 leading to a motor 105, and branches 147, 148 leading to expression devices or "controllers" 50, a pedal actuating-device 101, and to other parts. The distribution of the compressed air is governed by a vacuum created by a bellows 61 and distributed by a pipe 60. The branch tube 149 is controlled by a cock 150, while the main portion of the tube 146 is controlled by a valve 154, which can open and allow the compressed air to pass when the air is exhausted from the upper part of its casing through a tube 175. The action is as follows :-On opening the cock 150 and throwing a lever 135 to the right, so as to operate clutches 116. 126, the motor draws the tune-sheet from a music roll 141 on to a take-up roll 142 across a tracker board 54, the ports 55 of which are exhausted of air. Some of these ports are connected through tubes 33 with key striking-mechanisms shown separately in Fig. 6, their positions being indicated in Fig. 1 by 24 and 3. When a hole in the tune-sheet admits air to a cavity 27, a diaphragm 26 is forced to the right by a spring 31, thus closing a valve 29 and opening a valve 30, and so opening a chamber 12 to the space above a flexible diaphragm 8. Compressed air contained in a chamber 18 can now force open a valve 19, and reach the diaphragm 8, which it depresses, thus actuating the key striker 4. The valve 19 is carried on a spindle 20. and an additional opening can be given to it by a diaphragm 21, thus admitting more compressed air to the diaphragm 8 and causing the striker to actuate the key more forcibly. The movement of the diaphragm 21 can be caused by compressed air admitted through a tube 34 to one of the "controllers" above mentioned. These controllers are shown at 50, and consist of valves governed by vacuum by means either of some of the ports 55 below the tune-sheet, or push-buttons mounted in a board 88. They are six in number, and each is connected to all the notes of the same name and an adjacent note a semitone distant, the idea being that, as a note and its semitone are seldom sounded together, one emphasis apparatus will do for both. Thus, when the controller appropriate to F is in operation, all the F's and F sharps are in readiness for being sounded with emphasis whenever their note openings are uncovered by the tunesheet. A general forte effect is produced by a special device 99, which throws all the controllers into operation at once. For producing a piano effect, a valve 176 is used. This can also be controlled either manually or by the tune-sheet, and serves to reduce the pressure of the wind admitted to the key strikers. The pedal device 101 is also actuated in a similar way. At the end of the tune the lever 135 is moved to the left. This raises a valve 139. thus destroying the vacuum, and throwing out of action everything but the motor. The clutches of this are at the same time reversed, and thus the tune-sheet is re-wound on the roller 141. The apparatus can be actuated wholly automatically, if desired. all the movements being governed by holes in the tune-sheet. Thus the motor is controlled by a lever 216, which is acted on by pushes 210, 211, and these are controlled by holes in the tune-sheet, which admit air to ports in the hollow spindles of the rolls 141, 142.