Patent GB-818185-A (GB)
Title: Improvements in or relating to gramophones
IPC: G11B17/02
Filed: 1956-07-18
Abstract: 818,185. Automatic gramophones. HENKE, G. A. July 18, 1956 [July 18, 1955], No. 22190/56. Class 40 (2). In an automatic gramophone having a cam 13 which makes one revolution at each record change, a switch bar 6 is so linked with the cam that a short-circuit switch 33 for the pick-up is closed during each record change and after the last record of the stack has been played. The. gramophone is started by pressing a push button to move bars 6, 28 from the position shown in Fig. 1 to that shown in Fig., 3; the bar 6 moving switch lever 37 to close contacts 34, 341 of the switch 33, and the bar 28 turning a plate 21 about a pivot 22. Movement of the plate 2 I  frees a pin 19 so that a cam 16 is moved by a spring-pressed lever 24 pivoted at 25. The cam 16 is integral with the cam 13 which is moved so that its periphery is in driving engagement with the hub 4 of the turntable. The lever 24 coacts with a pin 30 on the bar 6. On release of the push button the pin 30 moves to a position c and causes a projection 31 on the bar 6 to open the contacts 32, 32<SP>1</SP> of the switch 33 whilst a lever 8 closes a switch 5 to rotate the turntable and the cam 13. Rotation of the cam 13 causes a pin 49 to rock a lever 41 about the pivot 25, and the lever 41 rotates a friction disc 44 anti-clockwise by means of a pin 45. A pin 46 on the friction disc engages the lever 37 to open the contacts 34, 34<SP>1</SP> after contacts 32, 32<SP>1</SP> have been permitted to close by movement of the bar 6 due to anti-clockwise turning of the lever 24 derived from the cam 16. Rotation of the friction disc moves a gauging finger (not shown) towards the lowermost record of the stack, a cam 43 moving with the finger. A projection 70 on the lever 41 co-operates with an arm 68 on a clutch plate 67 to rotate the plate, the pick-up arm and a lever 52 clockwise, an arm 53 of the lever 52 striking a stop 54 on the friction disc to limit the rotation. The pick-up is raised before rotation by the withdrawal of an inclined part 71 of the lever 41 from beneath the pick-up shaft 51. An arm 56 of the lever 52 then turns a stop member 59 about its pivot 60 to move a trip lever 58, also pivoted at 60, into engagement with the hub of the cam 13. After a record has been released from the stack by movement of the lever 41 the projection 70 on the lever 41 engages an arm 69 on the clutch plate to swing the pick-up over the edge of the record on the turntable, a pawl 56<SP>1</SP> on the arm 56 striking the cam 43 to limit the pick-up movement. The following clockwise movement of the lever 41 causes the inclined part 71 to slide under the shaft 51 to lower the pick-up on to the record whilst the cam 43 is swung away from the turntable the pawl 56<SP>1</SP> moving along a groove 43<SP>1</SP> in the cam. Further movement of the lever 41 lowers the cam 43 so that it will not interfere with movement of the pick-up. When the lever 41 returns to the position shown in Fig. 1, the contacts 32, 32<SP>1</SP> are opened and the pick-up is energized. The record is then played, the cam 13 being unable to rotate since the depression 14 is opposite the turntable hub. As the pick-up reaches the run-out groove of the record the trip rod 58 is swung by the arm 57 so that a pawl 27 on the plate 21 engages a projection 64 on the trip rod. A cam 66 on the turntable hub strikes the end of the trip rod and the plate 21 is pivoted clockwise to release the pin 19 so that the next record change is initiated. After the last record of the stack has been played the gauging finger meets no resistance on swinging towards the turntable and a hook 55 engages the lever 52 so that the pick-up is swung away from the turntable, and the switch 5 is opened whilst the contacts 32, 32<SP>1</SP> remain closed to mute the pick-up.