GB616352A - Improvements in or relating to gramophones, especially magazine gramophones - Google Patents

Abstract

616,352. Gramophones. HANSEN, H. C. Jan. 30, 1946, No. 2984. Convention date, April 29, 1944. [Class 40 (ii)] In a gramophone in which the movements of the pick-up arm are controlled by a cycling cam, said cam has a notch in which the driving wheel may idle during the playing of the record, a device being provided for locking the cam in position, and means for unlocking and urging the cam in a direction to engage the driving wheel automatically at the end of the playing of a record. In Fig. 1, a cam-disc 10 controls the movement of an arm 18 rigidly mounted on the shaft carrying the pick-up arm. During playing of a record an extension 50 on the arm 18 engages the side of an aperture 52 in a lever 48 which is frictionally connected by a pin-and-dot connection to a tap-tap member 56, one end of which comes into contact with a projection 64 on the driving shaft 20. During normal traverse of the pick-up arm, the lever 48 slips along the tap-tap member 56, but when the pick-up reaches the run-off groove the taptap member 56 moves to intercept the projection 64 and is pushed by it away from the cam disc 10. By means of pin 60, the pawl 28 on the lever 44 is withdrawn from engagement with the square recess 26 in the cam-disc 10, against the tension of a spring 46, after which the spring-loaded arm 32 moves the cam-disc 10 a small amount in a counterclockwise direction so that it engages the driving wheel 22. Fig. 2 (not shown), illustrates a modified form of the invention in which a second notch and square recess is provided in the cam-disc 10 to enable the pick-up arm to be brought to rest .in the swung-out position when no more records remain in the magazine. A linkage is also shown, whereby the second recess is rendered ineffective while records remain in the magazine. Details are also given of a switch-mechanism whereby the switch is manually set to the " On " position, but is automatically switched " Off " when the pick-up is in the swung-out position and no more records remain in the magazine.