Patent GB-637233-A (GB)
Title: Improvements in machine for playing disc-type phonograph records
IPC: G11B17/16
Filed: 1946-09-05
Abstract: 637,233. Magazine gramophones. LYNCH, W. A. Sept. 5, 1946, No. 26750. [Class 40 (ii)] In a magazine gramophone which plays both sides of the records by means of oppositely directed styli 16a, on the pick-up arm 15, records are supported for playing the undersides thereof by means of three retractable rubber-tyred wheels 60 which rest on the turntable 11, or a record thereon, and effect the necessary reversed direction of drive to that of the turntable 11. The cycle of operations after a record has been played is controlled by a cam-disc 30, Fig. 3, which is rotated 180 degrees during each cycle by means of a toothed wheel 31 on the turntable shaft 13, the said wheel 31 idling in one of the toothless sectors 32 while a record is being played. During each cycle, cam-surfaces 38 co-operating with a roller 25 on an arm 24, Fig. 5, control the horizontal movements of the pick-up arm 15 which is held in a neutral position between the stack of records and the turntable 11 by a rod 26 co-operating with a cam-surface 33. During a cycle prior to the playing of the underside of a record, a bar 46, Fig. 3, is moved to the right by means of a lever 50 pivoted at a point 51 and having a roller 85 which engages a cam-groove 55. The bar 46 serves to rotate the arms 45 in a clockwise direction so that the flexible blades 44 intercept all but the lowermost record of the stack, and the rigid blades 43 move clear to release the lowermost record on to the wheels 60, which have meanwhile been moved to the dotted position shown in Fig. 1 by means of a rod 68 coupled to one of the arms 45. The bar 46 also serves to bias the pick-up arm 15 in an upward direction by means of a spring 91. At the end of this cycle a roller 83 enters a recess 82 in a cam-surface 80, and, by means of a bell-crank lever 84 and link 89, a triangular plate 69 is rotated clockwise so that the rods 71 are drawn inwardly to lower the wheels 60, Fig. 4, on to the turntable 11, and the upwardly pointed stylus 16a comes into contact with the start of the record. At this moment the appropriate toothless sector 32 reaches the toothed wheel 31 and rotation of the cam-disc 30 is arrested. When the stylus reaches the end of the record the toothed wheel 31 is caused to re-engage the cam-disc 30, by means not shown, and the roller 83 rides up on to the plain part of the cam-surface 80, and thereby lifts the wheels 60 from the turntable 11 and raises the record which has just been played clear of the upwardly pointed stylus 16a. The pick-up arm 15 is then moved outwardly by one of the cam-surfaces 38 to the position shown dotted in Fig. 1. Continued rotation of the cam-disc 30 causes the arm 45, by means of the cam-groove 55, lever 50 and bar 46, to be rotated counterclockwise, as viewed in Fig. 3, so that the rigid blades 43 are returned to a position underneath the stack of records, the flexible blades 44 withdrawn, and the wheels 60 moved outwardly to the positions shown in full lines in Fig. 1 so that the record supported thereon falls to the turntable 11. The pick-up arm 15 is then moved, by means not shown, over the start of the record, the underside of which has just been played, and is lowered on to the record when a slope 34 on the camsurface 33 reaches the rod 26. At this moment the toothless sector 32 coincides with the position of the toothed wheel 31 and the cam-disc 30 is stopped in a position ready for the commencement of a cycle prior to the playing of the underside of a record, and so on.