Patent GB-1195406-A (GB)
Title: Automatic Return Device for Record Players
IPC: G11B3/095
Filed: 1967-11-10
Abstract: 1,195,406. Automatic return devices for pick-up arms. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 10 Nov., 1967 [22 Nov., 1966], No. 51375/67. Heading G5R. An automatic return device for the pick-up arm of a record player comprises an actuating lever mounted for movement from an initial position into a displaced position in response to actuation of an operating member, a locking device arranged to lock the actuating lever in its displaced position, and a driving plate linked to the actuating lever and resiliently connected to a damped further plate, the pick-up arm being mounted for vertical and return movement by movement of the further plate in response to movement of the driving plate. Assuming the pick-up arm, shown in end elevation at 4, Fig. 1, is located at the peripheral edge of a record to be played, a knob 2 on a shaft 7 is turned clockwise, secured to the knob is an operating lever 8 which, since Fig. 2 is a view of the underside of Fig. 1, turns in the direction of the (upper) arrow on Fig. 2. By withdrawal of lug 21 on operating lever 8 from switch 22, the switch closes to energize an electromagnet 12; the magnet 12 now holds a plate 9 forming part of a freely-pivoted actuating lever 10 which has been moved to the position shown by the operating lever 8. (Movement of lever 8 has also closed a turntable driving switch not illustrated). A link 23 is moved downwards by the actuating lever 10 and rotates a fanshaped driving plate 31 in the direction of the arrow. Plate 31 is linked by a spring 36 to a slow-moving plate 35 which has a cam strip 43 (see also Fig. 1) on its upper surface, and is secured to a shaft 28 having paddles 30 extending into a viscous oil 29, Fig. 1. Plate 35 does not move immediately with plate 31 because of the damping action of the paddles 30, but when eventually it reaches the position shown in Fig. 2 the shaft 37 of a pick-up lift 3 has been lowered by the cam strip 43 to the position shown in Fig. 1, thus lowering the pick-up arm. The record is now played, and the rotary shaft 40, Fig. 2, of the pick-up arm 4 eventually reaches the orientation shown in Fig. 2, where a "return" member 41, mounted on the shaft 40, is directed towards plates 31, 35. When playing of the record is completed the electromagnet 12 is automatically de-energized, whereupon a return spring 32, Fig. 2, rotates plate 31 to its initial position. The plate 35 is moved by the driving plate 31 in the same direction by means of a "kicking" member 33 pivoted to the driving plate 31 and partly slidable against an edge 42 on plate 35. Movement of plate 35 causes cam strip 43 to raise the pick-up arm from the record by means of shaft 37 and lift 3, Fig. 1, while engagement of "kicking" member 33 with "return" member 41, in passing, rotates the pick-up arm by means of its shaft 40. The turntable driving switch opens during this phase. If playing is to be interrupted in the middle of a record, knob 2 is turned counter-clockwise so that lever 8 is turned in the direction opposite the arrow from the position of Fig. 2 until lug 21 opens switch 22, thus de-energizing magnet 12. Spring 32 is thereupon able to rotate lever 10 clockwise through link 23, and to rotate 31 and, eventually, plate 35 to lift and swing the pick-up arm in the same way as at the finish of a record. For manual operation a button 16, Figs. 1 and 3, and with it a clamping member 26, is depressed against the force of a spring 24, whereupon a spring 20, Fig. 2, pulls the end 17 of a clamp plate 13 on to the top of the clamping member 26 as in Figs. 1 and 3. Arm 18 of clamp plate 13 is thereby rotated to cause notch 19 to engage a stop pin 11 on the operating lever 8, and a hook 15 on clamp plate 13 latches the end portion of actuating lever 10. When button 16 is released the mechanism 31, &c., is immobilized and the pick-up arm may be moved by hand. For release from manual setting, operating knob 2 is rotated counterclockwise, causing operating lever 8 to push arm 18 outwards (by means of pin 11); end 17 of clamp plate 13 is thereby pulled away from clamping member 26, spring 24 raises member 26, and the position of Fig. is regained.