GB272263A - Improvements in or relating to telephonic instruments - Google Patents

Abstract

272,263. Graham, M., and Graham, A., (Representatives of Graham E. A.), and Rickets, W. J. Feb. 9, 1926. Diaphragms; magnetic instruments. - The diaphragm of a telephone transmitter or receiver is supported by annular sets of flexible non- extensible radially-extending ligaments disposed in parallel planes. Two shallow cones 1, 2, Fig. 1, of stiff light material such as sheet metal or alloy or paper treated with a cellulose composition, are united at their peripheries and fixed to a light ring 3 suspended from a frame 6 by twoannular sets of ligaments 4. 5, e.g. of wire or thread. The apices may be connected by a strut 7. In a modification, Fig. 2, the cones are reversed, their peripheries are connected to the edges of the ring 3, and additional struts 7 are provided. Fig. 3 shows a single cone 1 supported by one set of ligaments 4<a> and provided with stays 8 connected at one end to the periphery of the cone and joined together at their other ends 8<a> where they are supported by the second set of ligaments 9. The junction 8<a> may be connected to the apex of the cone by a strut 7a. In a further modification a single fiat circular diaphragm is connected at its periphery centrally to, a ring such as 3, Figs. 1 and 2. Alternatively two flat circular diaphragms may be used each connected at its periphery to an edge of the ring 3.