Patent GB-104094-A (GB)
Title: Improvements in Talking Machines.
Inventor: MELLERSH-JACKSON WILLIAM JOHN
IPC: G11B17/02
Filed: 1916-05-11
Abstract: 104,094. Jackson, W. J. Mellersh-, (Sonora Phonograph Corporation). May 11, 1916. Periodic. - Relates to automatic stop-gears for talking-machines, of the kind in which a brake is applied at the end of a reproduction by the continued movement of the turntable after the stylus has ceased to advance, and consists primarilv in providing means for withholding the brake mechanism during the initial stages of a reproduction. Fig. 3 shows the mechanism in plan in the position assumed during the playing of a record. A bracket 23 clamped to the tone-arm carries an open frame 24, the outer part of which supports a slide 25 with a gap in its upper surface. Through this gap passes a pointer 26 pivoted at 26<a> to a frame plate 11 and co-operating at its pointed end with an arm 32. The turntable spindle 3 is coupled through reducing-gear to a spindle 20 carrying two cams 21, 22. The upper cam 22 cooperates with the end of the arm 32 and thrusts it intermittently towards the pointer 26. The lower cam 21 operates a spring- controlled slide 29, the outer forked end of which engages a pin 27 on the pointer and thus intermittently centralizes it. If the pointer 26 is central when the arm 32 is moved outwards, a pivoted frame 13 carrying the reducing-gear and the spindle 20 is moved backwards against the action of a spring 38, and a shoulder 34 engages a trigger 35 pivoted to a brake detent 36, moving a finger 51 of the detent out of engagement with the brake lever 48 and allowing a spring 50 to apply the brake to the turntable rim 4. While a record is being played, the tone-arm and its attached bracket 23 move the slide 25 frictionally, and the pointer 26 is thereby swung to one side or the other of its central position, according as the record is played inwards or outwards. The outward movement of the arm 32 is thus rendered ineffective. At every revolution of the shaft 20, the pointer 26 is returned to central position by the forked end of the slide 29 actuated by the cam 21. When the needle reaches the circular groove at the end of the record, the tone-arm and bracket 23 come to rest, and the pointer 26 remains central and is engaged by the arm 32, thus causing the brake to be applied. In order to prevent the application of the brake while the needle is being placed in starting position on the record, a timeconsuming device is provided comprising a lever 44 controlled by a spring 46 and carrying a pawl 43. This lever is rocked by the cam 22 and steps round a ratchet-wheel 42 having one long tooth 47 and a stop-pin 41. For one complete revolution of the ratchet-wheel 42, the pin 41 is removed from the arm 40 of the trigger 35 and consequently the trigger is free to turn and does not allow the brake detent 36 to be released. When a revolution is completed, the pawl 43 rests on the long tooth 47 and ceases to turn the ratchet-wheel, the pin 41 then forming an abutment for the arm 40 and allowing the brake detent to be released whenever the tone-arm comes to rest. When the brake detent 36 is released, either by hand or automatically at the end of a record, the arm 40 of the trigger advances the ratchet-wheel 42 so as to remove the long tooth 47 from under the pawl 43.