Patent GB-180370-A (GB)
Title: Improvements in or relating to gramophones or other sound reproducing machines
IPC: G11B3/095
Filed: 1921-01-17
Abstract: 180,370. Gaydon, H. A., and Creed & Co., Ltd. Jan. 17,1921. Transmitting power.-Relates to pneumatically-operated gramophones and the like and consists in providing automatic repeating-mechanism comprising a. pivoted track adapted to be raised and lowered by an air or like fluid-pressure motor to lift the sound-box off the record, return it to a predetermined starting-point, and replace it on the record, valves in the fluid-pressure system being controlled by the record-driving mechanism. The apparatus may be set to repeat a predetermined number of times, or for a given period, or indefinitely. The gramophone comprises a turntable 1 driven by an air motor 2, a pneumatic sound-box 3 carried by a tone-arm 4, and a. track or rail 21 which is pivoted at 22 and extends over the turntable and under a roller 20 on the tone-arm. The rail-operating motor consists of a cylinder 24 and piston 25 carrying a roller 26 on which the rail rests. Compressed air is supplied to the system through a pipe a, which is connected direct through a pipe h to a valvechest g. The pipe a also leads through a rotary valve b to a pipe c which has branch connections to the main motor 2 and to a secondary valve e. The latter leads to the sound-box 3 and to a silencer 19 into which the motor 2 exhausts. The valves b, e are alike controlled by spring-pressed pistons 10 working in cylinders 11, 11<a> each having a leakage port 13; the cylinders are connected by pipes 16, 14 respectively to valves 7, 5 in the chest g. The valve 5 and a similar valve 6 are controlled by cams u, v on a spindle t geared to the turntable-spindle. The valve 7 is under the control of a bell-crank lever 32, one arm of which bears against a notched flange 33 on a wheel x. This wheel normally gears with a worm w on the spindle t, but can be depressed temporarily, and turned by a knob 35 to set the notch 34 in a predetermined position relative to the lever 32, according to the number of repetitions desired. The setting is indicated by a pointer 36. After the setting has been made, the lever 32 is held down by the flange 33, allow. ing the valve 7 to close. Air is thus shut off from the cylinder 11, and the main valve b opens automatically, admitting air through the pipe c. During the ensuing operation of the gramophone, after each movement of the sound-box across the record the cams u, v open the valves 5, 6 and shortly afterwards close them. The opening of the valve 6 admits air to the cylinder 24 so as to effect the lifting of the rail 21 and thereby the return of the tone-arm to the starting-position, determined by a stop 31; the operation of the valve 5 causes air to pass to the cylinder 11<a> whilst the rail is being lifted and lowered, so as to divert air temporarily from the sound-box to the silencer 19. When the wheel x, driven by the worm w, has been returned to the zero position, the lever 32 enters the notch 34, the valve 7 opens, and air passes to the cylinder 11, thus causing the valve b to close, and stopping the working of the apparatus. If desired, the wheel x may be retained in the depressed position, in which case the gramophone repeats indefinitely. Means may be provided for closing the valve b after a predetermined time.