GB919154A - Improvements in and relating to gramophone pickups - Google Patents

Abstract

919,154. Pick-ups. COSMOCORD Ltd. June 5, 1959 [March 1, 1958; April 1, 1958], Nos. 7059/58 and 10405/58. Class 40 (4). In a piezo-electric pick-up for use with lateral cut or 45/45 records each of two styli is coupled to both of two piezo-electric elements by means of an open integral ring-like member 17 (Fig. 5) having two integral arms each of which connects one element to the stylus carrier 20 (Fig. 2), the lateral and longitudinal compliances of the arms differing from one another. Two bimorphs; of which one, 14, is shown in Fig. 2, are located within the casing 10, 11 by projections 13 on the inner walls thereof, their rear ends being located in a restraining pad 15 and their front ends being received in slots in the two upper sides of the square- or diamondshaped member 17. The pad 15, the member 17 and an intermediate pad 16 are all made of compliant material such as plasticized polyvinyl chloride. The forward part of the stylus carrier 20 consists of a thin walled tube 21, the front end of which is flattened and carries two styli 22, 23, while the rear part of the carrier 20 is a spring wire 24 having its forward end inserted into the tube 21 which is crimped at 25 (Fig. 1) and its rear end secured in a turnover mounting member 26. The shank portion 26a of the member 26 is accommodated in a groove in the underpart of the casing 10, 11, being held therein by metal spring member 30 the arms of which are passed beneath two lugs 31, 32 of the casing. The stylus carrier 20 and member 26 may be removed as a unit by withdrawing the spring member 30. The stylus carrier 20 engages in a groove in the lowermost part of the coupling member 17. The cartridge is mounted in a U- shaped cradle consisting of a relatively stiff portion 40 and a resilient portion 41 (Fig. 3) by springing it into position, a projection 43 on the front of the casing engaging in a hole in portion 41, and two projections 45 on the rear thereof engaging in a slot in portion 40. The lower arms of the member 17 have a compliance in the compression direction which is substantially less than that in the direction at right angles so that the two signals from a 45/45 recording are transferred to the respective bimorphs with substantially no crosstalk.