GB651757A - Improvements in or relating to electromagnetic pick-ups - Google Patents

Abstract

651,757. Gramophone pick-ups. ELECTRIC & MUSICAL INDUSTRIES, Ltd. April 7, 1948, No. 9678. [Class 40 (iv)] In a moving-coil pick-up for lateral cut records angular movement is imparted to the coil by a stylus arm which is substantially co-planar with the axis about which the coil oscillates and which is resilient in directions within that plane but has considerable stiffness in directions at right angles thereto. The pick-up comprises a U-shaped permanent magnet with pole-pieces 2, 3 mounted in a two-piece casing, the rear part of which consists of a plate 4 having a tubular extension 5 and lugs 6 serving to locate the magnet and as securing means for the front part (not shown). The coil 8 (Fig. 4) is wound on a rectangular elongated former 9 of insulating material, the ends of which extend into and are gripped by the ends of two lengths of rubber or like sleeving 10, 11 carried by a support 12 mounted on the extension 5 and having pairs of fingers 13, 14 which clamp the ends of the tubes 10, 11 remote from the coil. Extending through the former 9 at right angles is a shaft 15 provided with a stylus arm 16 coplanar with the longitudinal axis of the former and bent away from the coil to give suitable clearance between the pick-up and a record. The stylus arm is resilient in the plane containing the axis of the former but exhibits substantial stiffness in directions at right-angles thereto. The tubular extension 5 carries the leads 19 which are lead from the coil through the sleeve 11. The sleeves 10, 11 provide the torsional restoring forces for the coil.