Patent GB-1155510-A (GB)
Title: Improvements relating to Miniature Record-Players
IPC: G11B3/36
Filed: 1968-03-13
Abstract: 1,155,510. Disc record players. CSF-COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. 13 March, 1968 [17 Nov., 1967], No. 12292/68. Heading G5R. A record player comprises: a turntable; a fork-shaped pick-up arm having an upper prong carrying a pick-up having a stylus and a lower prong; a first cam carrier part pivoted under the turntable for causing the arm to retract on co-operation of the part with the lower prong; a second cam carrier part for lifting the arm for optional rejections of it in the course of playback of a record; first means for bringing the second cam carrier part into co-operation with the lower prong and the first cam carrier part; and switching means for controlling the rotation the turntable. The bottom of the casing 1, Fig. 1, has a raised flat part 100. The turntable 2 (shown transparent to assist description) rotates about a spindle 4 on a shoulder 7 and has, mounted about a pivot 51 on its underside, a first cam carrier part including a cam 50, a part 5 and a pin 52. The pick-up arm 3 is in the form a fork: the upper prong carries a stylus, not shown, while the lower prong has a horizontal projection 31, Fig. 1, and a downwardly-directed projection 32. Held down on to flat part 100 by springs, not shown, is the second cam carrier part in the form of a plate 6, Fig. 2, which has at one end a vertical button 60, Figs. 1 and 2, and at the other end a thin downwardlyextending cam 63 having a cam edge co-operating with a fixed ramp 13, Fig. 2. The turntable motor and amplifier are fed through two switches in parallel - one, 9, normally closed, and the other, 10, normally open, Fig. 1. The cam carrier part 5, 50 is normally urged against shoulder 17, Fig. 1, by a spring 53, Fig. 2. Stylus return after playback.-When the stylus has left the end of the sound groove and is in the final circular groove, the distance of the lower prong of the pick-up arm 3 from the spindle 4 is such that cam 50, integral with part 5, comes into engagement with projection 31 on the lower prong during rotation of the turntable 2. While the turntable continues to rotate, the cam raises the prong, thereby lifting the stylus from the groove; thereafter, engagement of projection 31 with the free end of part 5 (beyond cam 50) results in part 5 being swivelled about pivot 51 (against the spring force), the part 5 in turn pushing pick-up arm 3 outwards to its rest position. At this position, the lower prong opens switch 9, whereupon all movement ceases. Starting playback.-Button 60 is raised to close switch 10 momentarily. The resulting current pulse suffices to rotate the turntable 2 until part 5 disengages from the lower prong of pick-up arm 3. Cam carrier part 5, 50 is then returned to its normal position by spring 53, permitting arm 3 to descend away from switch 9, which thus closes automatically and maintains the rotation of the turntable. The rest position of arm 3 is chosen so that, on its descent, the stylus enters the lead-in groove of the record. Playback continues until automatic return as described above. Interrupting playback.-Button 60 is pushed until a catch 66 on it engages a catch 80, Fig. 2. Cam 63 is thus pushed up ramp 13 so that plate 6 rises, and lifts the pick-up arm by contact with projection 32 to disengage the stylus from the record. During continued rotation of the turntable, pin 52 on part 5 engages a ramp 64, Fig. 1, on plate 6. This engagement causes cam carrier part 5, 50, to swivel outwards about pivot 51 and push the pick-up arm 3 outwards to its rest position, where it opens switch 9, whereupon all movement ceases.