GB373158A - Improvements relating to apparatus for the electrical reproduction of sound - Google Patents

Abstract

373,158. Gramophone pick-ups. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London, AULT, L. B., 172, Allesley Old Road, and ROBINSON, T. F., 6. Dane Road, Stoke, both in Coventrv. Feb. 17, 1931, No. 5020. Addition to 310,284, [Class 40 (iv), Telephones &c.]. [Class 40 (iv).] In an electromagnetic sound reproducer as described in the parent Specification wherein an armature is pivotally mounted between the abutting ends of a pair of pole pieces and has a portion extending at right-angles to the pivotal axis thereof and adapted to engage at its end a resilient member mounted on the polepieces and subjected to substantially no initial compressive or frictional force, the resilient member is in the form of a rod or tube arranged so that it is subjected to a bending movement about its axis on movement of the armature about its pivot. The gramophone pick-up shown comprises a horseshoe magnet 1 provided with bipartite polepieoes 2 enclosing a coil 3. An armature 4 passing through the coil is provided with a shaft 5 adapted to be clamped with interposed resilient material between the lower extensions of the polepieces. The upper recessed end 6 of the armature, which is located between the upper recessed polepiece extensions, receives one end of a resilient rod 8, the other end of which is adjustably secured by a nut 12 in a clamping member 9 supported by the bridge member 10 fixed to pillars 11 on the polepieces. If desired, the rod 8 may be replaced by a resilient tube adapted to fit over the upper end of the armature.