Patent GB-1136657-A (GB)
Title: Record player having light-activated switching circuit
IPC: G11B17/12
Filed: 1966-11-28
Abstract: 1,136,657. Record-player switching circuits. V-M CORP. 28 Nov., 1966 [28 Sept., 1966], No. 53182/66. Heading G5R. A phonograph record player comprises a tone arm for playing records, first means arranged to effect a functional operation of or associated with the record player, and control means, (arranged to actuate the first means) comprising a circuit including a light-activated switch operatively connected to the first means, a light source directing light towards the switch to activate it, and a wand operatively connected to the tone arm and arranged to move therewith between the light source and the switch during record play to prevent actuation of the switch by light from the source, the wand passing from between the light source and the switch when the tone arm reaches a predetermined position where it permits light from the source to pass to the switch and thereby cause the first means to effect the functional operation. Transferring records.-Records R<SP>1</SP> Fig. 3, are stacked around a cap 32 surmounting a fixed spindle 13 and terminating at its lower end in out-turned fingers. The lowermost record is supported by, and may be lowered by, retractable fingers 31 pivoted in a rod 33 but extending, in the position shown, through slots in spindle 13. When rod 33 is lowered, the lowermost record is carried down on fingers 31 until they are retracted by contact with the unslotted part of spindle 13, whereupon the record falls on to the turntable 12. The rod 33 rests on a train of balls 34 which are permitted to descend at the appropriate time by pivoting of a lever 35 about 36. Such pivoting is effected by counter-clockwise rotation of a cam 39, Fig. 1, which has a cam track 38, Fig. 3, on its under-side engaging a follower 37 on the lever 35. Tone-arm movement.-A circular cam track 42 with a plateau 56 on the upper face of cam 39 co-operates with one end of a lift plate 44, which is pivoted at 45 and raises a friction clutch member 49, Fig. 4, into contact with part 50 of the tone arm 15 whenever the follower of lift plate 44 is in the depressed portion 59 of track 42 during rotation of the cam. The tone arm 15 is thereupon moved outwards beyond the records, and then inwards to the starting position, by a link 51 which is connected at 52, Fig. 4, to the stem 48 of clutch 49 and is constrained to move it, in a slot 47 in plate 44, by a further cam track 43. This cam track co-operates with a roller 53 at the junction of link 51 and a further link 54 pivotable about a fixed point 55. When the plateau 56 reaches the lift plate 44 again the clutch 49 is released; thereafter the tone arm 15 is free to be traversed inwards by the sound groove on the record. (The tone arm is raised, when appropriate, by a rod 41, Fig. 4, operated by conventional mechanism. ) Automatic operation of cam 39.-The cam has been stopped before tone arm 15 moves inwards on a disc record and, as the tone arm does so, a wand 83, secured to it at 85, Fig. 4, continues to obscure an aperture 80 in the light path between a lamp, a lens (not shown) in a housing 71 and a photoelectric cell (not shown), above the housing. When the stylus 17 reaches the innermost position on the record, the wand 83 moves beyond the aperture 80, whereupon the now-illuminated cell completes the circuit of the driving motor 40 of cam 39 to set it in rotation. The aperture 80 is immediately reobscured by wand 83, but a spring-urged lever 89 now released by projection 88 on the cam opens, by link 92, a shutter (not shown) to keep the photoelectric cell illuminated. The cam is thus maintained in motion until, at the end of the cycle, projection 88 on cam 39 serves to close the shutter again (aperture 80 being at this time obscured). Record-lowering and tonearm movement are appropriately synchronized by relating cam tracks 43 and 38. Primary operation of cam 39.-At the outset, in order to lower the first record, and to locate the tone arm in playing position over it, a switch by-passing the photoelectric cell is momentarily closed at the same time as the closing of the switch governing all circuits of the record player; cam 39 is thereby rotated sufficiently to release lever 89, after which the cycle continues as described.