Patent GB-878379-A (GB)
Title: Improvements in or relating to phonographs
IPC: G11B21/12
Filed: 1957-12-04
Abstract: 878,379. Gramophones. THORENS S. A. Dec. 4, 1957 [Dec. 22, 1956; Sept. 26, 1957], No. 37815/57. Class 40 (2). A photograph comprises a motor-driven turn-table and a pick-up arm in which the power necessary to automatically position the pickup over the first record groove is stored in a spring motor by the action of manually setting a lever which conditions the machine to play a record of a particular diameter. A turntable D (Fig. 2), is driven by a motor M through a belt 5, a three-step pulley 6 and an idler wheel 7, the speed is changed by a control 14. The wheel 7 is mounted on an articulated arm 8 and 9 (Fig. 3), pivoted to the baseplate at 3 and fitted at the joint with a spring 10 to maintain driving contact. An automatic clutch mechanism which controls the position of the idler wheel 7 comprises a lever 86 which is pivoted at 84 and has a hook 87 which engages the axle 88 of the idler wheel and moves it against the action of the spring 10, when a rod 85 is pulled by a lever 81 acted on by a spring 89. The movement of the lever is controlled by a roller 83 running on the edge of a cam 52 and also by a sloping face y on a lever 29. The motor M is controlled by a switch 43 which has an operating member 42 actuated by a pin 40 on a lever 39 pivoted at 37 to the lever 29. A pick-up arm B (Fig. 8), is mounted on a horizontal pivot 17 carried by a holder 18 secured to a bush 19 (Fig. 9), which is free to revolve on a vertical spindle 20. Fastened to the top of the spindle is an arm 23 (Fig. 8), which carries an adjustable stop 25 which engages a face 26 (Fig. 8), formed by part of the holder 18. The lower end of the spindle 20 carries an arm 27 (Fig. 9), fitted with a pin 28. This pin engages a sector 102 (Fig. 3), with a pin 28. This pin engages a sector 102 (Fig. 3), which is pivoted at 103 and has a stepped cam face m. During rotation of the sector in an anti-clockwise direction the pin 28 moves along the face m and swings the pick-up arm into the correct radial position to engage the first groove of a particular size of record. During rotation in a clockwise direction the pin runs along one of the grooves 108, 109 or 110. In the rest position the pick-up arm is raised above the surface of the turn-table and the pick-up is outside the diameter of the turn-table. To start the machine the operator places a finger in one of the holes 92, 93 or 94 and rotates the lever 91 and also the lever 29 in the direction of the arrow # 5 . Rotation of the lever 91 pulls the rod 101 and rotates the sector 102 and also tensions the spring 95. Rotation of the lever 29 switches on the motor M through the lever 37 and the sloping face y of the lever 29 rocks the lever 81 and allows the idler wheel 7 to transmit the drive. When the lever 91 is released by the operator it returns to its rest position under the influence of the spring 95 and is locked in that position by the hook 107 engaging the lever 56. The lever 29 returns under the influence of the spring 34, and carries with it the lever 46, the end 51 of which engages with the face 67 on the cam 52 and rotates it against the action of the spring 53 to the position shown in Fig. 2. Rotation of the cam 52 causes a roller 58 to move on to the portion c of the cam thus rocking the lever 56 against the spring 59 and allowing the rod 60 to move so that the lever 61 (Fig. 9), can rotate about the pivot 62 and release the rod 64 holding the pick-up arm in the raised position, so that it is lowered on to the record. Rotation of the cam also brings the part u (Fig. 3) of the cam under the roller 83 and maintains the idler wheel 7 in the driving position. At the end of the record a tap-tap lever 71 (Fig. 2), of known type cooperating with a striker 74 is moved in the direction of the arrow   # 2  and strikes the pin 48 carried by the rod 47 (Fig. 3), which disengages the pawl 51 from the face 67 and allows the cam 52 to rotate due to the action of the spring 53 until the nose 55 abouts the stop 54. Rotation of the cam allows the lever 56 to rotate under the influence of the spring 59 so that the rod 60 pulls the lever 61 (Fig. 9), and raises the pick-arm which can then be moved outwards manually. Rotation of the cam also allows the roller 83 (Fig. 3), to move on to the part o of the cam and disengage the idler wheel 7. The motor M is switched-off by the lever 71 striking the member 42. A record rejection device comprises a member R pivoted at 112 and connected by a rod 113 to a lever 77 which is pivoted at 78 and has an arm 114 which moves the tap-tap lever 71 in the direction of the arrow # 2 . In a modification (Figs. 11, 12 and 13, not shown) the speed of operation of the mechanism, after the lever 91 has been released, is controlled by an air dashpot. Specification 854,209 is referred to.