GB257173A - Improvements in diaphragms for the reception and conversion of sound waves - Google Patents

Abstract

257,173. Walker, W. L. Feb. 22, 1926. Subaqueous audible signals; detecting subaqueous sounds.-Comprises a sonant receiving and transmitting device adapted to be inserted in an opening in the skin of a ship including a diaphragm forming a continuous portion of the ship's skin and made of hard resilient non-corrodible insulating material together with sound transmitting means operated by the diaphragm. A housing 2 is fitted to an opening in the skin 1 of the ship and receives a flanged ring 4 preferably formed in one with the diaphragm 3 of hard rubber compounds containing cellulose such as cellulose acetate. The ring 4 is screwed internally to receive a ring 5. The diaphragm 6 supporting the microphone 8 is of smaller diameter than the diaphragm 3 and is secured at the rim between rubber gaskets 10, 11, and clamped in place by a gasket 12 and the ring 5. A central rubber pad 13 is fitted and this may be formed in one with the gasket 10, being connected thereto by spokes. By varying the thickness and dimensions of the diaphragm 3 and the pad and gaskets and the pressure of the ring 5, the diaphragm may be made resonant to desired vibrations and remain unaffected by undesired vibrations. The pad 13 when formed separately may be centred on a boss on the diaphragm. In a modification shown in Fig. 5 for cases where it is desirable to insert and remove the outside, the ring 21 is screw-threaded both internally and externally and the diaphragm 22 has a boss for engaging the threaded rod 24 of the microphone 25.