Patent GB-406354-A (GB)
Title: Improvements in talking machines
IPC: G11B3/28
Filed: 1932-08-25
Abstract: 406,354. Gramophones. ELECTRIC & MUSICAL INDUSTRIES, Ltd., Blyth Road' and GEORGE, J. I., 21, Mount Road, both in Hayes, Middlesex. Aug. 25, 1932, No. 23842. [Class 40 (ii).] The reproducer arm 7 of a continuously-playing gramophone is mounted upon a support adapted to rotate in a bearing in the machine in accordance with the horizontal swinging movements of the arm and to make up and down movements of limited extent, and a friction member 16, which is fixed on such support, is adapted to move into frictional engagement with a stationary part of the machine when the support is raised so as to offer a given degree of frictional resistance to swinging movements of the reproducer arm while the support is raised. The arm 7 may be formed as a tube having a vertical portion 9 clamped in a collar 10 carrying trunnions 11 by which the arm 7 is mounted for movement about a horizontal axis between the arms 12 of a yoke 13 fixed to a vertical pillar 14. The pillar 14 projects through apertures provided respectively in upper and lower plates 1, 2, and the friction member 16, in the form of a disc of fibre &c., is mounted on the lower end of the pillar. The pillar 14 is rotatable about a vertical axis and is also capable of limited movement vertically to bring the disc into or out of contact with the undersurface of the plate 2. When the playing of a record is completed, a cam shaft 6 is set into rotation so that a cam 24 rocks a frame 20 about a horizontal axis in such manner as to cause a bridge piece 26 to contact with a pin 27 carried by a bracket 18 on the collar 10 and thereby lift the reproducer 8 from the record. The position of the pin 27 is so arranged having regard to the length and weight of the arm 7 and reproducer 8 that the lift imparted to this pin first raises the pillar 14 to bring the disc 16 into engagement with the plate 2 and then rocks the arm 7 about the trunnions 11. A roller 33 on a T-shaped lever 31 is then engaged by a cam 351 on the shaft 6 so that the end of the lever 31 moves clockwise and swings the arm 7 outwardly by engagement with a pin 29 on a bracket 28 carried by the pillar 14. After a short interval, during which a new record may, in the case of a magazine machine, be fed to playing position, the cam 35<1> no longer operates the lever 31, and a cam 35, also on the shaft 6, engages a second roller 34 on the lever 31 so as to swing the latter in counter-clockwise direction. The arm 7 is thereby swung inwardly due to the engagement of the pin 29 with a lever 37 pivoted on a pin 36 on the lever 31. The lever 37 is urged into engagement with the pin 29 by the action of one end of a coil spring 39 mounted on the pin 36, the other end of the spring being engaged with one of a number of serrations formed on the edge of a plate 38 on the upper end of the pin 36. During the first part of the return movement of the lever 31, the action of the friction disc 16 in resisting movement of the arm 7 causes the lever 37 to lag, and the spring 39 is loaded until a lug 41 on the lever 31 engages the edge of the lever 37, so that levers 31, 37 then move together and swing the arm 7 inwards into a position with the stylus over the smooth portion near the outer edge of the record. The arm 7 is then lowered by the frame 20, but the disc 16 is maintained in contact with the plate 2 until a proportion of the weight of the reproducer 8 and arm 7 is supported on the record. As the friction between the disc 16 and plate 2 is lessened, the spring 39 is able to overcome such friction and move the lever 37 about its pivot 36 and thereby swing the reproducer arm 7 gently inwards to engage the stylus with the first record groove.