GB450791A - Improvements in or relating to electrical hearing aids - Google Patents

Abstract

450,791. Instruments for deaf persons. REIN, L. V. KAHN-, and REIN, V. G. KAHN-, (trading as REIN & SON, F. C.), 30, Charing Cross Road, London. July 3, 1935, No. 19034. [Class 40 (iv)] In a hearing-aid device in which a permanent magnet and coils are mounted on a vibratory member adapted to be placed in contact with the mastoid or other bone, a casing which encloses the magnet and coils is secured relatively to the vibratory member by means at one end of the casing which clamp the casing to the vibratory member and means at the opposite end which clamp the vibrating member to the casing. The vibratory member 6, which is shaped to conform to the mastoid bone, is secured to the casing 7 by a screw 10 passing through the member 6 and at the opposite end by a pair of screws 8 which pass through the casing 7 and engage threaded holes in metal blocks 9, Fig. 4, formed integrally with the member 6. The magnet is of laminated form and comprises portions 12 of rectangular form carrying pole pieces 13 of truncated triangular shape with extensions on which are mounted bobbins 14 for the coils. The outer end of each pole piece has a brass block 17 secured to the magnet by screws 16 and to which is secured by a screw 19 a rectangular diaphragm 15 of soft iron, e.g. Swedish iron. The vibrating member 6 is connected to the diaphragm 15 by means of a metal insert 22 engaged by screws passing through lateral lugs formed on the diaphragm. The external leads 24 are inserted into holes near the base of the members 9 and are pierced by grub screws 25 from which connection to the coils is established by screws 23. Spring washers may be incorporated between the diaphragm 15 and the plate 6.