Patent GB-470455-A (GB)
Title: Improvements in or relating to portable piano players
IPC: G10F3/00
Filed: 1936-02-10
Abstract: 470,455. Piano-players; bellows. BARNETT, H., and COOKLIN, I. Feb. 10, 1936, No. 3971. [Class 88 (i)] [Also in Group XXVIII] A portable player to be placed on the keyboard of a pianoforte comprises within the casing an electric motor driving a pump, the suction of which both drives an air motor driving the spools and also operates the playing accenting and tempo actions, with a switch for the electric motor. The casing 10, which is adjusted in position by longitudinally adjustable feet 11 and vertical screws 12, is divided into three sections A, B, C, by plates 13, 14. The electric motor 21 in section B drives through high-reduction gearing a shaft 20 with two cranks at 90‹ operating the suction pump 17 in section A through two connecting rods 18, 19. The pump 17 comprises two bellows-members 55, 56 rocking on a fixed beam 57 so as to form four separate exhausting bellows which are opened and closed out of step. A spring- pressed relief valve 61 mounted on a spring- pressed bellows 60 is opened in the travel of the bellows 60 by a stationary pin 61b to prevent the suction becoming excessive. A pipe from the pump 17 leads, through a speed-governor device and tempo control (operated by a fingerlever 96), to the air motor 33 in section C, this motor being mounted on a frame 34 rocked into one of three positions by a finger lever 84 or automatically by a pneumatic 35. The forward drive of the tune sheet is obtained from a pinion 82, rotated by the motor 33, engaging a, gearwheel 75 on the spindle of the take-up roller 28, and operating against the action of a brake. On conclusion of a piece, tracker-bar operation of a valve 50 deflates pneumatic 35 and thus rocks the frame 34 into neutral position. When frame 34 is rocked by hand into the other end position, for re-winding, pinion 82 is put into mesh with a wheel gearing with a pinion 72 on the spindle 30 for the music-roll, and the brake is removed. The rocking frame 34, which is centred in its three positions by a spring pawl, in its two end positions closes the circuit to the electric motor 21, but leaves the circuit open in its central (neutral) position. Another pipe, 47, leads from the pump 17 to the treble and bass exhaust-trunks through an accenting device 38 operated by valves 53, 54 either from treble and bass finger-levers 118, 119, or from the tracker-bar through ducts which may be closed by a hand-valve to cut out the automatic accenting. The main valve of the accenting device 38 is closed automatically to cut off the pump 17 from the actions, when the driving mechanism is rocked to re-winding position, by air admitted through a valve opened by movement of the frame 34. The striker-pneumatics 39 and their valves 42 are mounted on the baseboard 40, which is kept clear of other mechanisms and through which the key-strikers project. The central portion 66 of the trackerbar is slidable step-by-step by a rotary fingerkey 68 and eccentric, for transposition. The tracker-bar is slidable as a whole to ensure correct tracking, by a rod 130 connected to a pair of pneumatics 36 operated by valves 51, 52 controlled by the two end tracker-ducts. Specifications 470,456 and 470,457 are referred to.