GB334562A - Improvements in means for automatically stopping or controlling phonographs - Google Patents

Abstract

334,562. Stockton, J. P. March 22, 1929. Starting and stopping.-Relates to means for automatically stopping or controlling gramophones, of the kind in which a lever driven from the tone-arm and a lever driven by the motor have a differential movement when the tone-arm changes its motion at the end of playing, such movement being utilized through trigger mechanism to apply a brake to the turntable, or to open a switch controlling the driving motor, or to initiate the action of repeat or record-changing mechanism. According to the invention, the trigger mechanism is carried by the motor-driven Lever and is released upon the sudden inward movement of the tone-arm which results when the stylus passes into the usual concentric or eccentric terminal groove. Figure 2 shows a lever 20 movable about a pivot 21 by a pin 17 on the tone-arm and a lever 25 mounted on a pivot 26 on the lever 20 so that relative movement of the levers can take place when the switch or brake is to be actuated to stop the machine. The lever 25 has pivoted thereto a trigger-lever 31 and a switch or brake-operating lever 30, a pin 36 on the lever 31 holding the lever 30 in the off position against the action of a, spring 43. The lever 30 also carries a toothed member 41 which, towards theend of the pla.ying movement, engages the motor-driven worm 42 to ensure synchronous movements of the levers 20, 25. When the movement of the tone-arm accelerates at the end of the playing movement due to the needle entering a special guiding groove, the end 34 of the lever 20 engages the end 33 of the lever 31 to release the lever 30 and, in the example shown, cause the insulating member 53 to pass between the spring contacts 47 and break the circuit of the driving-motor. Stopping can be effected independently of the special groove by the engagement of a pin 61 on the lever 31 with a fixed cam 60. The parts are reset by the return of the tone-arm, the trigger 31 beinp re-engaged with the lever 30 when a link 53 engages a fixed stop 58. A hand-operated rod (not shown) may engage the pin 54 to stop the motor at any time. The same mechanism can be employed to close a switch through an auxiliary motor to operate, for example, a record-changing mechanism. Fig. 11 shows means whereby the lever 30 operates to lift a lever 70, trip a lever 81, and release a spring- controlled lever 77 which serves to actuate the brake-lever 73.