GB632233A - Improvements relating to sound reproducing machines - Google Patents

Abstract

632,233. Magazine gramophones; mounting pick-ups; turntables. MORRIS, S. M., and MORRIS, R. April 29, 1947, No. 11474. [Class 40 (ii)] A sound reproducing machine comprises a platform a raisable to engage centrally the underside of a disc record and lift it clear of a ring support j, swung into the path of the platform from a magazine, to a position where the record moves a weight m clear of its support n and is clamped by it, pick-ups q, r arranged to be raised and swung about a spindle v so that one engages the top or underside of the record and means for reversing the direction of rotation of the platform. The platform is raised by a cam h on a spindle i engaging a bell-crank lever g and linkage e, el, d acting on the lower end of the platform spindle. Dependent on the selected one of two positions of spring-loaded toggle linkage 23, 22, a roller 16 on a lever 17 is adapted to be engaged or not by the hook end of a supplementary lever 14 pivoted to a main lever 11 carrying the lever 17, cams 19, 21 engaging the levers 11, 14 so that when the hooked lever 14 engages the roller 16 the pickup spindle v is raised to a lower extent than when the lever 14 is free, and the record side to be played thereby selected. The toggle linkage setting may be varied at any time to determine which side of the next record will be played but the cam 21 prevents the roller 16 entering or withdrawing from the hook end of the supplementary lever 14 until the record being played is completed, the cam 21 then being in a position in which its recess 60 permits lowering of the roller 20 and lever 14. Alternatively, if both sides of a record are to be played successively one cam with projections of different radial height replaces the cams 19, 21, levers 11, 14 and toggles. Connected with the main lever 11 is an arm 43 connected with an arm 46 and rod 47 to which a worm is secured engaging alternative driving elements and reversibly driving the platform dependent on the position of the rod 47, lever 11 and record side being played. A further cam 34, Fig. 8, on the spindle i engages levers 32, 31, the latter abutting and controlling the bias of an arm 30 on the pick-up spindle v and of the pick-ups to a record commencing position under the action of a spring-loaded block 35, the tone arm then being free due to the block 35 engaging an abutment 41 and the levers 32 31 entering a recess 39 in the cam. Stops may be arranged to permit one tone arm only to be freed to traverse the record. In a modification the platform is threaded on the spindle by a split nut so that it travels axially with the record along the spindle depending on the then commenced direction of rotation of the spindle, and the tone arms are vertically fixed. In a further modification a single pick-up pivoted on the tone arm, and connected by gearing to an arm operated by engaging one or other of two stops, is automatically moved to the top or underside of a record when the tone arm is raised or lowered. In the Provisional Specification records alternatively may be fed axially down a revolving spindle from a magazine above the playing position on to a turn-table, which with a further turn-table brought to bear on top of the record are slotted to pass across the spindle to a position coaxial therewith, the lower turntable then engaging with the spindle and being driven by it.