Patent GB-408294-A (GB)
Title: Improvements in or relating to arrangements for automatically controlling the playing of gramophone records
IPC: G11B17/02
Filed: 1932-07-04
Abstract: 408,294. Gramophones. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and JACOBY, H. C. E., c /o General Electric Co., Witton, Birmingham. July 4,1932, No. 12763. [Class 40 (ii).] Relates to an arrangement for automatically controlling the playing of disc gramophone records comprising means to raise the tone-arm when a record has been played, to return the tone-arm to the starting position, to lower the tone-arm, and to guide the tone-arm by the engagement of a part on the tone-arm with a fixed guide in such a manner that the tone-arm is first given a lateral deflection and then led vertically down to the correct position on the record. According to the invention, the continued movement of the tone-arm lowering means after the stylus has engaged the record is made to disengage the aforesaid part of the tone-arm from the guide ; and this guiding device can be adjusted or set for 10 or 12 inch records as desired. As shown, the guide is an upwardly extending slightly curved plate 34, Figs. 7 and 8, with two vertical slots 35, 36 each opening out into a V-shaped notch adjacent spring controlled pivoted flaps 37, 38, one or the other of which is put in operative position by a lever 46 according to the setting of the shaft 49 of a record feeding pillar 5 for 10 or 12 inch records. The part of the tone-arm adapted to engage the guide is a pin 30 projecting from an arm 29 on a shaft 27 journalled in the tone-arm 18. The shaft 27 is connected by a crank to one end of a lever 26, Fig. 1, pivoted inside the tone-arm at 25 and adapted to bear at its other end on a plunger 28, Fig. 3, which serves to raise and lower the tone-arm. The shaft 27 has also another crank 32 connected to a spring 33, which tends to hold the pin 30 away from the guide 34. The tone-arm is carried by a pillar 22 connected by a slotted crank 80 and a spring 82 to a lever 78 controlled by the face 62 of a cam 61. The plunger 28 is operated by a lever 71 pivoted at 72 and controlled by the periphery 63 of the cam 61. Another face of the cam controls the record feeding means. The automatic operation of the cam and mechanism associated therewith may be as described in Specifications 374,908 and 407,952. When a record has been played, the tone-arm is lifted by the plunger 28 and swung out by the lever 78, a fresh record is placed on the turntable and the tone-arm moved in over the starting groove. The finger 30, which was thrust forward by the action of the plunger 28 in lifting the tone-arm, deflected the spring flag 37 or 38 during the outward swing of the tone-arm but now abuts against the flag, which cannot yield in this direction ; and when the tone-arm is lowered by the plunger 28, the pin 30 strikes one of the sides of the V-shaped mouth of the slot 35 or 36 thereby giving a lateral deflection to the tone-arm, after which the pin rides down the slot 35 or 36 to position the stylus correctly in the starting groove of the record. The continued movement of the plunger 28 allows the spring 33 to withdraw the pin 30 from the guiding groove to permit the tone-arm to swing inward while the record is being played.