Patent GB-823773-A (GB)
Title: Improvements relating to record-changing gramophones or record players
IPC: G11B17/02
Filed: 1956-01-31
Abstract: 823,773. Record changers. STAAR, M. J. H. Jan. 31, 1956 [Sept. 17, 1955], No. 3089/56. Class 40 (2). In a record-changing gramophone or record player of the kind in which the drive between the motor and turntable includes change-speed mechanism manually-operable to adjust the rotational speed of the turntable, this mechanism also including a " zero " position whereby the drive between the motor and turntable is interrupted, there is a control element sensitive to the presence of a record in the distribution position ready to be placed upon the turntable during a record-changing operation and adapted to be moved into an operative position when there is no record in such distribution position, that element when in the operative position being adapted to cause movement of the speed-control lever to the zero position thereof during the subsequent operation of the record-changing mechanism. As shown in Fig. 2, the arm 5, which has a forked end adapted to engage a stack of records on a supporting stem, is secured to a rod 9 slidable vertically in a sleeve 10. As shown in Fig. 4, a control plate 13 is rocked about a spindle 15 by a follower arm 14<SP>1</SP> provided with a head 14<SP>2</SP> which engages in a groove in a rotatable cam 14. A lever 18 pivoted on the spindle has a finger 19 engageable with the plate, movement of the latter causing swinging movement of the lever, and a lever 20 provided with a longitudinal slot 21 rocks about and also slides radially with respect to the spindle; the two levers are pivotally connected to a link 22 provided with a lug 24, and a tension spring 23 urges the link in a direction away from the spindle 15. A spring 32 secured to the lever 18 is anchored to the plate 13, and a spring 33 attached to the lever 20 is secured to a tongue 34 on a bell-crank lever 35 pivoted on a pin 36 and provided with an arm 37. The changespeed lever 7, Fig. 3, pivots on a pin 25 having a radial projection 27 which moves in a slot 28 parallel to and separated by a partition 31 from a slot 30, both slots being formed in a frame 29. Operation.-Rotation of the cam 14 causes movement of the control plate 13 about the spindle 15 in the direction of the arrow F, Fig. 4, to a position 13<SP>1</SP> and the ramp 16 on the plate engages a rod 17 to lift the pick-up arm of the apparatus, the levers 18, 20, also being rocked about the spindle to positions 18<SP>1</SP>, 20<SP>1</SP> and the link 22 moving in the slot 30 towards the position 22<SP>1</SP>; during such movement of the plate the raised pick-up arm is swung clear of the turntable and the lowermost record of a stack of records is released to fall on to the turntable, further rotation of the cam 14 causing movement of the plate back to the initial position thereof. Under the influence of the spring 33 the lever 35 moves to a position 351 when the plate 13 takes up the position 13<SP>1</SP>, and the rod 9 of the arm 5 descends to rest on the arm 37 of the lever 35; when the arm 37 is swung back to the initial position thereof the rod drops behind the arm as shown in Fig. 4. When the last record has been played and the record-changing mechanism is again set into operation and the plate 13 moves to the position 13<SP>1</SP>, the lever 35 is prevented by the rod 9 from swinging about the pin 36 and the spring 33 is put under tension by movement of the lever 20 with the plate so that the link 22 moves to a position wherein the lug 24 of the link enters a notch 40 in the frame 29 thereby preventing return movement of the levers 18, 20 when the plate 13 moves back from the position 13<SP>1</SP>. The end of the lever 20 now lies in the path of a cam element on the cam 14 and which engages and slides the lever in a direction causing pivoting of the link 22 to release the lug 24 from the notch 40, the levers 18, 20 in consequence being returned under the action of the spring 32 to the initial positions shown in Fig. 4, and the lug travelling along the slot 28 in the frame 29 to engage the projection 27 and thus shift the speed-control lever 7 to a zero position; the lug then again enters the slot 30 in the frame 29, and the lever 20 moves clear of the path of the element 41 (Fig. 5, not shown). In a modification, the rod 9 is constructed to enable the lever 7 to be shifted to a zero position during any operation of the recordchanging mechanism whether or not such operation takes place following the playing of the last record of a stack and to accomplish this the rod has an extension carrying a boss and of dimensions so as to clear the arm 37 of the lever 35 during rocking movement of the latter. If it is desired to cause the lever 7 to return to the zero position manual raising of the arm 5 results in the boss being brought into the path of the arm 37 to result in the lug 24 travelling along the slot 28 to effect shifting of the lever 7. The reciprocating movement of the link 22 may be adapted to act upon a speed-control lever rotatable about a vertical axis. Specification 652,924 is referred to.