Patent GB-544545-A (GB)
Title: Improvements in and relating to devices for automatically controlling the movements of a pick-up arm in talking machines provided with means for changing discs automatically
IPC: G11B17/02
Filed: 1940-05-06
Abstract: 544,545. Automatic gramophones. BLAKE, W. H. (Paillard & Cie Soc. Anon., E.). May 6, 1940, No. 8086. [A Specification was laid open to inspection under Sect. 91 of the Acts, Nov. 11, 1940.] [Class 40 (ii)] In automatic gramophones of the kind in which a pile of discs is supported above the turntable by lateral supports, a separate cam is provided for effecting each separate movement of the pick-up and an eccentric or its equivalent for effecting the record changing operation, and all these cams and the eccentric are secured rigidly on one and the same shaft 35, Fig. 4, adapted to be driven one revolution by the turntable motor through a clutch when the pick-up reaches the end of a record. As shown in Fig. 4, the shaft 35 carries a gear wheel 33 in mesh with a pinion 30 fast with a clutch member 31 adapted to be clutched to a shaft 29 driven by the turntable spindle 2. Universal joints 32 are provided in the shaft 29. During the revolution of the shaft 35, a cam 43 acts on a lever 44 on a spindle 45 fast with a wedgeshaped lever 46 which bears against the bottom end of a rod 48 to lift and lower the pick-up. Another cam 37 acts on a pin 38 to move the pick-up outwards. A cam 36 or 36a acts on the pin 38 to return the pick-up over the edge of the fresh record; and a spring finger 72 or 72a on the cam 36 or 36a urges the pick-up into the starting groove; the pin 38 is moved up or down to engage the cam 36 and finger 72 or the cam 36a and finger 72a according to the size of the fresh record as described in Specification 544,546. Another cam 49 on the shaft 35 acts on a lever 50 to re-set the control mechanism. A cam 81 acts on a lever 82 to re-set the fork mechanism serving to control the position of the pick-up on the record according to the size of the record as described in Specification 544,546. An eccentric (not shown) also on the shaft 35 serves to operate the record-changing mechanism also as described in Specification 544,546, and a cam 40 acts on a lever 42 to release the clutch at the completion of the revolution of the shaft 35. The clutching operation is controlled by an arm 1, Fig. 1, which follows the horizontal movements of the pick-up arm. During the play of a record, the arm 1 bears on a lever 6 and turns that lever clockwise. This movement is transmitted through a pin and slot connection 12, 9 to a lever- 7 which is periodically pushed back by a finger 3 on the turntable spindle 2. When the pick-up enters the quickpitch groove at the inner end of the record disc, the increased rotational movement of the lever 7 allows the end 15 of a catch 13 pivoted at 13<SP>1</SP> on the lever 7 to engage over the nose 17 of a lever 16 pivoted at 16<SP>1</SP> on the base plate 11, so that when the lever 7 is next pushed back by the finger 3, the lever 16 is also turned and releases the nose 22 of a lever 20 pivoted at 201 on the base plate 11. This lever is turned clockwise by a spring 21 ; and a pin 26 on the lever turns a lever 27, Fig. 4, about a pivot 27<SP>1</SP>; and this turns another lever 28 pivoted at 41 by means of the pin and slot connection 28<SP>1</SP>, 28<SP>11</SP>. A lever 25 on the same pivot 41 and frictionally coupled to the lever 28 is therefore also turned and causes the clutch' 31 to engage to start the record changing and pick-up returning operations. When these operations are completed, a cam 49 on the shaft 35 acts on a bell-crank lever 50, 52 pivoted at 51, and a pin 34 on that lever acts on the lever 6, Fig. 1, to return this lever 6 and the lever 7 to the initial position. Finally, a cam 40 acts on a lever 42 pivoted at 41 and bearing on a lug 25A on the lever 25 to turn this lever back to release the clutch 31. To prevent the machine stopping before the completion of this cycle of operations, a switch 77, Fig. 6, in the motor circuit is closed by the lever 25 when this turns to cause the engagement of the clutch. The switch 77 is in parallel with the manual switch 80 and therefore keeps the motor circuit closed independently of the manual switch so long as the clutch is in engagement.