Patent GB-639442-A (GB)
Title: Automatic phonograph mechanism
IPC: G11B17/16
Filed: 1948-03-23
Abstract: 639,442. Magazine gramophones. TRIGGS, W. W. (Farnsworth Research Corporation). March 23, 1948, No. 8552. [Class 40 (ii)] In an automatic phonograph the recordchanging cycle is effected by a unitary control device in the form of an L-shaped plate lever 51, Fig. 4. The plate lever includes a cam 61 Tor lifting and lowering the tone arm and stops 66, 67 for controlling the tone arm rotating mechanism. The lever also operates the recordejecting mechanism. A turntable 2, driven by a motor 4 is mounted on a base-plate 1, Fig. 2. A sleeve 9 mounted on the turntable is journalled in a bracket 11 so that a recordsupporting spindle 13, having an offset shoulder 14, may be removably mounted through the sleeve 9. The tone arm 17 is pivotally mounted on a standard 16 at 21. Vertical movement of the tone arm is effected by a pin 24 slidably mounted in a rotatable sleeve 23. The record ejecting mechanism may be as described in Specification 605,201, and comprises a pivoted arm.30, Fig. 5, the lower end of which is engaged by an upstanding portion 75 on the lever 51. The upper end of the arm 30 co-operates with a record ejecting plate 35. A horizontal record supporting shelf 26 has oppositely disposed shelf portions 27 and 28 for co-operation with either 10 or 12 inch records respectively when rotated manually through 180 degrees. A sleeve 25 is also rotated with the shelf 26, thus positioning a pin 29, Fig. 3, for co-operation with the lever 51 when 10 inch records are played. The lever 51 is slidably pivoted on a stud 52 and has formed in it a mutilated internal gear rack 50 having portions A, B, C, D, which engage a pinion gear 54 secured on the sleeve 9. Upon initiation of the record-changing cycle, the gear 54 co-operates with the mutilated gear moving the lever 51 to the position shown dotted at E. This causes the cam 61 to operate the pin 24 and raise the tone arm. The stops 66, 67 actuate the tone arm by engaging. a downwardly projecting pin 69 fixed to the free end of a lever 71 which is attached to the tone arm. Movement of the lever 51 into position E thus causes outward movement of the tone arm. As the gear 54 engages the portion B of the gear 50, the lever 51 is moved into the position F causing the upstanding portion 75 to operate a lever 30 for ejecting the record from the stack on to the turntable. At the same time the pin 24 engages an extension 62 to maintain the tone arm in the elevated position. The portion C of the gear 50 then co-operates with the gear 54 to move the lever 51 to the position G. Assuming a 12 inch record is to be played, the stop 67 engages the pin 69 to move the tone arm inwardly over the record. If 10 inch records are to be played the pin 29 is depressed by the cam 25A. The pin 29 then engages the end 82 of a lever 81 on movement of the lever 51 from position F to G, thereby moving the end 83 of the lever 81 inwardly over the stop 67 for co-operation with the pin 69 to position the tone arm inwardly the required extra distance. Portion D of the gear 50 causes the lever 51 to be moved back to its original position, causing the pin 24 to lower the tone arm on the record by riding down the cam surface 62A. The lever 51 is also supported during movement by the cam follower 94 of a cam 91 depending from the base plate. Initiation of the change cycle is effected by a lever 105 urged in an anti-clockwise direction by clutch mechanism on the tone arm spindle. Lever 105 urges a lever 108 mounted on lever 51 towards the gear 54 which has a projection 112. During playing of a record the projection 112 engages surface 115 on lever 108 once each revolution so as to maintain it in the starting position. When the tone arm is radially accelerated inwardly, however, the lever 108 is moved to such a position that projection 112 engages the face 116, thereby throwing the lever 51 to the left so that the gear wheel 54 is brought into engagement with gear portion A. The lever 108 is reset by means of a pin 98. Specification 605,201 is referred to.