GB299537A - Improvements in or relating to electro-mechanical translating devices, such for example as loud speakers - Google Patents

Abstract

299.537. Trouton, M., and Wireless Music, Ltd. Aug. 5, 1927. Drawings to Specification. Magnetic instruments.-Relates to an electromechanical vibration translating device, such as a loud-speaker, of the kind in which the relative movement of the armature and magnet pole surfaces is at least in part rotational and consists in connecting the member to be driven by, or adapted to drive, the armature to the armature at a point situated between the centre and heel thereof. The armature is defined as those parts of the vibratory member which lie, at any moment, vertically above the stationary cooperating surface or magnet pole surfaces. The end of the armature nearer the real or virtual axis of rotation thereof is referred to as the, heel, whilst the opposite end is referred to as the toe. The parts are so dimensioned and disposed that, as the armature moves, the point at which the resultant attractive force acts, i.e. the centre of force, moves in such a manner that the moment of the resultant attractive force about the real or virtual axis of rotation of the armature varies according to a substantially linear law with the displacement (towards and away from the co-operating surface) of the point of attachment of the armature to the driving or driven member. The point of attachment of the driving or driven member to the armature coincides with the position of the centre of force in the position of rest of the armature, the centre of force moving from one side to the other of the point of attachment as the armature moves from its innermost to its outermost position during vibration. The parts are preferably so dimensioned and disposed that as the armature moves away from its position of closest proximity to the co-operating surface, the centre of force moves towards the toe of the armature. A relatively flexible armature is preferably employed which is so mounted that the flexure thereof increases as the armature moves from one working position to another away from the co-operating surfaces. Preferred constructions, together with the dimensions of the various parts are described in the Complete and both Provisional Specifications. Specification 293,131 is referred to.