GB419205A - Improvements in or relating to gramophones - Google Patents

Abstract

419,205. Gramophones. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and JACOBY, H. C. E., c/o General Electric Co., Witton, Birmingham. Feb. 7, 1933, No. 3745. [Class 40 (ii).] An automatic control mechanism for a gramophone, described particularly with reference to a mechanism for switching off a driving motor and applying a brake when a record has been played, comprises a bent lever 8 mounted by a screw 9 on a sleeve carrying the tone arm &c. 6. A lever 17 pivoted at 14 on a fixed plate 1 secured to the gramophone is pressed into frictional engagement with a sector 13, also pivoted at 14, by means of a spring tongue 18. The sector 13 has a step 15 on its periphery, which rocks a lever 40 to close a switch 37 to start the driving motor, when the sector is rotated by a pin 12 on the lever 8 as a result of the tone-arm being swung to starting position. The lever 17 carries at its free end a doublearmed lever 21, pivoted at 20, one arm 22 being pressed by a leaf-spring 25 into contact with a fixed stop. Towards the end of the audition period, the part 11 of the lever 8 engages a pin 16 on the sector 13 and thereby frictionally rotates the lever 17, which rotation swings the lever 21 so that a face 27 on the arm 23 of this lever moves into the path of a rubber pad 30 on an arm 29 mounted on the turntable spindle 3 and is struck back to replace the lever 17 at each revolution of the turntable. This continues until the needle enters a quick run-in groove on the record whereupon the arm 23 is rocked sharply so that the end 28 of this lever is struck by the pad 30, thus causing the lever 17 to actuate the pin 39 to open the switch 37, and allowing the spring 45 to rock the arm 44 to apply a brake 47 to a flange on the turntable. In a modification, the contact 60 for making or breaking the motor circuit is carried by a rocking plate 58 which is pivoted at 65, and which carries the brake pad 62. The sector 52 is rigidly connected to arms 53, 54, the sector having one step 67, which, by means of a lug 66 and pin 64 on the plate 58, sets the lever 56, and a second step 70 which actuates a lever 69 to lock the lever 56 in set position. When, during playing, the tone-arm 55 engages the pin 82 on lever 54, the sector 52 is rotated clockwise to release the lever 69 and plate 58 so that at the end of the playing period the lever 56, on actuation by the arm 76, may rotate the plate 58 by means of the pin 64 and thus break the motor circuit and apply the brake 62.