Patent GB-617917-A (GB)
Title: Improvements in and relating to a talking machine with automatic record changer
IPC: G11B17/16
Filed: 1946-06-12
Abstract: 617,917. Magazine gramophones. THORENS, R. June 12, 1946, No. 17558. [Class 40 (ii)] A magazine gramophone for playing both sides of the records, in which records are stacked on a detachable centre shaft 11 revolving in opposite direction to the turntable 5, has means for controlling the pick-up arm 20 for playing the underneath sides of the records on the stack 12 and the upper sides of records on the turntable 5 consisting of a single cam-member 51 having divided paths 128, 129, the one 128 controlling pick-up movements with regard to the upper record, and the other 129 the lower, means being provided to automatically open and close each cam path 128, 129 alternately by a switch 132, and a single cam path 127 joining said divided paths 128, 129 to control the intermediate position and horizontal movements of the pick-up arm 20. The pick-up arm 20, which is provided with two reproducing heads in a single case, is controlled in its upwards, downwards and horizontal movements by a lever 134 having a pin 126 which engages the cam paths 127, 128, 129. During playing of records on the turntable, contact of the stylus 8 with the records is maintained by the weight of the pick-up arm 20. During playing of records on the stack, contact of the stylus 24 with the upper record is maintained by means of a blade spring 158 acting against the underside of the pick-up arm 20, Fig. 7 (not shown). The cam-member 51 is driven, via an idler gear 48 on a movable plate 53, by a pinion 47 on the lower motor 1 which also drives the turntable 5. An upper motor 16 drives the detachable shaft 11, the records being supported by a projection 13 from which they are released one by one by means of a spring-loaded plunger 26, Fig. 3, acting on a member 31 which, under the influence of a pin 30 attached to the plunger 26, moves to the position in Fig. 4 (not shown) so that the tongue 31a unseats the lowermost record. The plunger 26 is operated by a bellcrank lever 46 connected by a rod 93 to a lever 86 having a roller 84 which engages a cam 82 on a cam-member 71. The cammember 71 is coupled to the cam-member 51 by gearing having a 1 : 2 ratio, so that the cammember 51 makes two revolutions to each one of the cam-member 71, and records are thereby released at every other excursion of the pick-up arm 20. The cam-member 71 is provided with a second cam 83 which engages a roller 105 on a lever 107 coupled by a spring 108 to a lever 99. The position of the end 991 of the lever 99, which sets the lever 118 and thence the initial position of the pick-up at the start of a record, is determined by the position of a roller 104 resting against the underside of the stacked records. When the lowest record of the stack is a 12-inch record; the roller 104 and the end 99<SP>1</SP> of the lever 99 take up the positions shown in Fig. 1, but when the lowest record is a 10-inch record, the roller 104 engages the edge of the record, and its position and that of the end 99<SP>1</SP> of the lever 99 differ accordingly, and so set the lever 118 to the alternative position for lowering the pick-up arm on to a 10-inch record. After each side of a record has been played, the switch 132 is moved to its alternative position by means of levers 175, 178, Figs. 10 and 13, and cam 180 on star-wheel 182, which is rotated a quarter-turn at each revolution of the cam member 51 when it strikes the pin 184 on the lever 185. To enable playing of a record to be repeated, the lever 185 may be switched to the position shown in chaindotted lines in Fig. 10. During this operation the end 187 of the lever 185, Fig. 10, or the end 194 of the lever 188, strikes the upturned end of clutch lever 75, which rotates counterclockwise about the point 76, and thereby disengages the drive to the cam-member 71 for half a revolution, so that operation of the cams 82, 83 are suspended during one revolution of the cam-member 51.