GB266271A - Improvements in or relating to telephone loud speakers - Google Patents

Abstract

266,271. Brown, S. G. Nov. 28, 1925. Lcvd-speakers; magnetic instruments; diaphragms.-In a telephonic loud-speaker of the kind having a large conical diaphragm, without a horn, the diaphragm is enclosed between two protecting cones which form a casing, being connected at its apex to the vibratory actuating member such as a reed, and at its outer edge to the periphery of the enclosing cones. The cones project inwardly towards the actuating part or movement of the loud-speaker, which part is enclosed in the casing in which the cones are comprised. The light conical diaphragm A, which may be made of paper, is, in the construction shown, secured by a thin flexible ring a (such as tissue paper) to a ring F of wood &c., which is clamped between the flanges of cones B, C enclosing the diaphragm. The cone B is truncated, and is open at the truncated portion, over which is fitted a perforated plate b<2>, for the emission of sound. The rear cone C, which is also perforated, is mounted on a casing D carried bv a standard d. The electromagnet H, preferably of V-form, is shown as mounted in the casing D, the ends of the magnet are connected by a laminated armature h, carrying the receiving coils h<1>. The vibratory reed G, which is attached to the apex of the diaphragm, is mounted on a plate J, adjustably carried by a screw. In a modification, the magnet and reed are mounted in front of the apex of the diaphragm, upon the truncated portion of the front cone B. The Provisional Specification describes an adjustable connection between the diaphragm and the reed, and states that to allow of ready access to the adjusting device the outer cone has a removable cap at its apex. Specification 261,506 is referred to in the Provisional Specification.