Patent GB-810954-A (GB)
Title: Improvements in or relating to record changers
Inventor: BARA EDWIN STANLEY
IPC: G11B17/16
Filed: 1956-01-16
Abstract: 810,954. Automatic gramophones. WEBSTER-CHICAGO CORPORATION. Jan. 16, 1956, No. 1462/56. Class 40 (2). A record changer having automatic cycles for the sequential playing of a number of records of different diameters includes a turntable 10 provided with means for releasably supporting a stack of records 97, 98 and 99 and means for dropping one of the records on to the table during each cycle, a tone arm including a transducer adapted for vertical movement and horizontal swinging movement relative to the turntable, indexing means 90 having a normal position and a position corresponding to each of a number of record diameters, means operable at the beginning of each cycle for operating the index means corresponding to the smallest diameter record in the stack, means actuated by the indexing means for urging the tone arm into an initial reproducing position corresponding to the diameter of the record dropped on to the turntable during a cycle, and means operable in response to the position of the indexing means for varying the speed of the turntable to correspond to the requisite reproducing speed of the record dropped. As shown, the turntable 10 is rotatably mounted about a non-rotating spindle mechanism 13 connected to a pivotally mounted rocker-arm 28 carrying a roller 52 engaging a cam path 51 formed on the underside of a rotatable cam gear 29 and serving to actuate the record-dropping mechanism. The teeth 33 on the cam gear 29 are interrupted so that the latter is periodically disconnected from a pinion 32 on the turntable hub 17 at a predetermined point where a spring-loaded plunger 34 coacts with a cupped projection 36 formed in the motor-board 1 for yieldably locking the cam gear in a normal inactive position. A rocker arm 44 pivoted on a rotatably mounted bracket 47 carries a cam follower pin 42 which rides in an undulating groove 43 formed in the cam gear 29. Ordinarily, during reproduction, the pinion 32 rotates in the interrupted portion of the gear teeth 33 but at the initiation of each automatic cycle the cam gear 29 is rotated out of the inactive position thereof by means responsive to the position of the tone arm when sound-reproduction of a particular record has been completed and the pinion 32 is brought into mesh with the teeth 33 so that the cam gear 29 is rotated through 360 degrees until the interrupted portion of the teeth 33 is again opposite the pinion 32. One revolution of the cam gear imparts radial and lateral movements to the rocker arm 44 to raise and swing the tone arm out of the reproducing position, release the lowermost record on to the turntable, swing the arm inwardly to either 7, 10 or 12 inch record reproducing position, and then set the arm down on to the record to be reproduced. A lever 63 which moves with the tone arm carries a pin engageable with the indexing assembly 90 to limit the inner swing of the arm according to the diameter of the record dropped. Indexing assembly.-A flag 90a mounted on a shaft 93 has an inclined face 91 engageable by a 10-inch record 98 or a 12-inch record 99. At the initiation of an automatic changing cycle, a record, in dropping, cams the flag outwardly so that the shaft 93 is rotated a predetermined distance and the travel of the pin in the lever 63 is limited by a stepped cam plate 89 in a position such that the tone arm is lowered in the correct position for the record. After the record has been deposited on the turntable the flag 90a is moved to the outermost position thereof and to effect this movement a channel-shaped bracket 96 mounted on the shaft 93 and normally urged by a spring 93a to a lower position is formed with the cam plate 89 which has pivotally mounted thereon a latch 105 provided with a shoulder 105a engaging the underside of the plate 89 and a projection 105b behind which the end of a lever 104 formed on the rocker arm 44 locks as the latter moves upwardly; as the rocker arm moves transversely the bracket is rotated to bring the flag to the innermost position thereof and the lever 104 disengages from the projection 105b so that the bracket is returned by the spring 93a to the lower position. Automatic change-speed mechanism.-An arm 200 attached to the bracket 96 is secured to a drawbar 202 which is guided for horizontal movement in a bracket 204 and has an apertured inner end for the sliding support of pushrods 206, 208 mounting knobs 210, 212 adapted to be engaged by a dog 214 pivoted to an ear 216 depending from the rocker arm 44. The push-rods are coupled to a lever 149a secured to a shaft 123 which forms part of a speed selector assembly and is rotated manually for selective engagement of one of the steps 162, 162a, 162b or 162c on the shaft 151a of a motor 152 with an idler wheel 153 that frictionally engages the turntable. Rotation of the lever 149a effects axial movement of a push-rod 150 which affords sliding movement of a cam 159 below the shaft 151a and having steps 159a, 159b, 159c and 159d corresponding respectively to turntable speeds of 78, 45, 33 1/3 and 16 r.p.m.