GB723981A - Improvements in or relating to hearing aids - Google Patents

Abstract

723,981. Spectacle frames. HOLLINGSWORTH, M. H. Nov. 14, 1951 [Nov. 20, 1950], No. 26702/51. Class 97 (1). [Also in Group XXXIX] The microphone, receiver, amplifier and batteries of a hearing-aid are all concealed in the bows of a spectacle frame. Either an airconduction receiver or a bone-conduction receiver may be used. The amplifier comprises three miniature tubes with resistance-capacity couplings and a transformer output. One bow 20, Fig. 3, is recessed to accommodate a boneconduction receiver 22b, the batteries 24, 25 and the transformer 23, the batteries being held by spring contacts 29. The other bow 21, Fig. 4, accommodates the microphone 30, the miniature tubes 31, 32, 33, the resistancecapacity units 34, 35 and a combined volume control and on/off switch 43. The components are interconnected by wire conductors W or by printed circuits or by some of each. Wires may be moulded into the front of the frame as shown in Fig. 7. Each bow is provided with a cover to conceal the components, the cover for the bow 21 having slots to give access to the microphone. As shown in Fig. 3, a bone-conduction receiver 22b is fixed near the end of the bow 20 so that it engages the mastoid bone. If an air-conduction receiver 22a, Figs. 10, 11, is used, it is interchanged with the transformer 23 so that the tip of a small tube 52 from the receiver can be fitted into the ear. The tube is made of metal or plastic and is held by a fitting 51 which snaps into the receiver 22a. The cover plate for the bow may conceal the fitting 51 or may have an aperture so that the fitting and the tube may easily be removed.