Patent GB-449987-A (GB)
Title: Improvements in magazine gramophones
IPC: G11B17/16
Filed: 1935-08-19
Abstract: 449,987. Magazine gramophones. HOLSTENSSON, A. H., Motala, Sweden. Aug. 19, 1935, No. 23288. Convention date, Aug. 28, 1934. [Class 40 (ii)] Relates to magazine gramophones, of the kind in which a pile of records is located above the turntable, and in which, at the end of the playing of a record, a cam mechanism operated from the turn table by a friction roller effects the necessary movements of the tone-arm and releases a fresh record to fall on to the turntable. According to the invention, the friction roller is mounted on an arm forming part of or engaging a lever which normally engages a recess in a cam disc so as to keep the roller out of contact with the turntable, the lever being adapted, after a predetermined movement of the tone-arm across the turntable, to be rocked into such a position as to bring the friction roller into engagement with the turntable, and to be held in this position by the cam disc during ono revolution thereof. In the machine shown, the records 16, Fig. 2, are threaded in a pile on a spindle 15 projecting from the turntable, and rest on a pair of opposed supports 13 extending laterally from rotatable uprights 3. A pair of projections 14, also provided on the uprights 3, are angularly and vertically displaced relatively to the supports 13, the arrangement being such that when the uprights are partially rotated in one direction and then reversely, by means of a spring-controlled push-rod 11, the members 13, 14 effect the release of the lowest record in the pile. The tone-arm or pick-up arm 19 is pivoted at 20 on a bent arm 21, Fig. 3, secured to a sleeve 22 which is rotatably supported in a socket 23. A slidable pin 25 below the pick-up arm passes through the sleeve 22 and rests at its lower end on a cam flange 26, Fig. 7 on a cam disc 27, which is mounted on a shaft 28. A lover 29 secured on the lower end of the sleeve 22 has two shanks 30, 31 adapted to be actuated bv a roller 32 mounted on the cain 27. The lever 29 is also provided with a segment 33 frictionally engaging a clamp 34 mounted on a shaft 35. An arm 36, carrying a friction roller 37 adapted to engage the edge of the turntable 2, is secured to the shaft 35, on which is also mounted a plate 38, free on the shaft and adjustable relatively to the arm 36 by means of a screw 39. The plate 38 has a projecting arm 41, the free end of which bears against the cylindrical periphery of the cam disc 27, or enters a recess 42 therein. The roller 37 is fixed on a shaft 46 journalled on the arm 36, the shaft being geared to the cam disc 27 through a train of wheels 49 ... 52 intermediate between a pinion 47 and a wheel 48. An arm 43 is detachably and adjustably secured to the upper end of the shaft 35, and carries a roller 45 in the path of the pick-up arm 19. The operation of the machine is as follows :- Whilst a record is being played, the free end of the arm 41 lies in the recess 42 in the edge of the cam disc 27, and the friction roller 37 is out of contact with the edge of the turntable 2. When, at the end of the record, the needle enters a largepitch run-off groove, the pick-up arm 19 engages the roller 45 on the arm 43, turning the latter and thereby the spindle 35 and arm 36, so that the roller 37 is brought into engagement with the turntable. By this means, the roller drives the cam disc 27 through the wneels 47, 48 and intermediate gearing, and the recess 42 moves away from the arm 41 ; thus the cylindrical edge of the disc 27 keeps the roller 37 in engagement with the turntable until the disc has made one revolution. During this rotation of the disc 27 the pin 25 is first raised by the cam flange 26 on the disc, and by upward pressure on the arm 19, lifts the pick-up from the record. Next, the roller 32 on the disc 27 strikes the shank 31 of the lever 29, and by rotating the lever swings the pick-up arm 19 outwardly. As soon as the arm is clear of the turntable, a projection 53 on the underside of the disc 27 moves the push-rod 11 longitudinally, and so effects the release of a fresh record, which drops on to the turntable. The rod 11 is returned by a spring to normal position when the projection 53 has cleared it. The arm 19 is swung inwardly over the fresh record, by engagement of the roller 32 with the shank 30 of the lever 29, and the cam flange 26 then allows the pin 25 to descend so that the pick-up is lowered on to the record. Shortly afterwards, the recess 42 again passes under and frees the end of the arm 41, and the resilience of the friction roller 37 causes it to move out of driving engagement with the turntable. If the records in use are of the kind having an eccentric termination groove, the oscillating movement imparted to the pick-up arm at the end of the playing of a record effects the engagement of the friction roller 37 with the turntable. This is brought about by means of frictional engagement of the segmental end 33 of the arm 29 with the clamp 34 mounted on the spindle 35. As the clip is oscillated, it causes the arm 36 to swing, bringing the roller 37 repeatedly into engagement with the turntable until the recess 42 in the cam disc 27 has moved away from the arm 41 whereupon the driving of the cam disc proceeds and the action previously described occurs.