GB319425A - Improvements in electro-magnetic reproducers for use with gramophone and the like records - Google Patents

Abstract

319,425. Oliver Pell Control, Ltd., and Oliver, C. June 30, 1928. Gramophone pick-ups; magnetic instruments.- A gramophone pick-up comprises a U-shaped permanent magnet with coils and pole-pieces mounted thereon, an armature yieldingly connected to another oscillatory member or members which is or are in turn yieldingly supported in the rigid frame of the reproducer, the additional oscillatory member, or members s collectively, being of greater mass than the armature, and rubber or like damping means having substantially no natural oscillation frequency inserted between the armature and the additional oscillatory member or members and between the latter and the rigid frame of the reproducer. The construction shown comprises a magnet A to one limb of which is secured a bracket L carrying the coils B and pole-pieces C. Screwed to the other magnet limb is an iusulating bracket F to which in turn is secured a channel-shaped member G through the flanges of which are passed adjustable screws G<1>. The tips of these screws are recessed to receive the points of screws H which serve as pivots for a second channel-shaped member I which constitutes the additional oscillatory member. The screws H also serve to secure to the member I a flat spring J to the middle of which is secured an armature K of lesser mass than the member I and adapted to receive the stylus K<1>. Rubber &c. damping blocks M are arranged between the flanges of the bracket L and member I, and the armature is also damped by a rubber &c. block O inserted between it and a plate P against the back of which bear screws Q so that the gap between the armature and pole-pieces can be adjusted. The block O is preferably made stiffer than the blocks M.