GB127731A - Improvements in Stop Mechanism for Talking and like Machines. - Google Patents

Abstract

127,731. Marks, E. C. R., (Columbia Graphophone Manufacturing Co.) June 12. 1918. Actuated by speed regulators; periodic.-Talking and like machines are automatically stopped at the end of a reproduction, or upon a reduction of the speed of the machine, by the engagement of two members, one of which moves proportionally to the feed movement of the tonearm, the other being actuated at a determined speed independently of the motor of the machine. The engagement of the two members may close an electric circuit and energize an electro-magnet for releasing a brake or stop lever. Fig. 4 is a part plan of machine, and Fig. 5 is a detail plan of the co-acting members. An arm 21 secured by a ring 30 to the vertical portion ot the tone-arm 15 carries a pin 39 engaging a slot in a sector-shaped plate 22 pivoted loosely on a shaft 28. A slight braking-action is exerted on the plate by a spring 34. The plate 22 carries an upright pin 40 and an insulated post 36 through which is passed a contact-screw 37. Between the pin 40 and the screw 37 lies an arm 23 driven by a friction washer 33 from the shaft 28, which is rotated at a determined speed by an independent motor, for example, by a spring motor 35. The determined speed is preferably slightly less than that of the plate 22 during a normal reproduction. Thus, while the tone arm is travelling normally across a record, the arm 23 is out of engagement with the screw 37 and is driven by the pin 40. If the speed of the machine and tone arm is reduced, or if the tone-arm ceases to advance, the independent motor causes the arm 23 to leave the pin 20 and to engage the contact-screw 37. A circuit is thus completed through battery 24, electro-magnet 26, switch 45, and the machine frame. The magnet attracts its spring-controlled armature 42 and withdraws a pin 41 from engagement with a lever 19 which is then swung by a spring 20 into the position shown in dotted lines, and arrests the machine. At the same time the battery circuit is opened at the switch 45. When the tone-arm is returned to starting position the pin 39 first opens the contact 37 by engaging an extension 46 of the arm 23, and then returns the plate 22 and the arm 23 to their original position. The machine is re-started by operating the lever 19 until it engages behind the pin 41. The independent spring motor 35 is wound up by reciprocating a ratchet arm pivoted on a pin 47 and projecting beyond the turntable rim.