GB794347A - Improved binaural hearing-aid device - Google Patents

Abstract

794,347. Hearing aids. HOLLINGSWORTH, M. H. Dec. 15, 1954 [July 15, 1954], No. 36345/54. Class 40 (4). Independent hearing aid systems are fitted in the two bows of a spectacle frame. Each bow comprises a shallow container x, Fig. 4, and a lid y, Fig. 5, the lid being recessed so as not to foul the components in x. The amplifier circuit uses transistors 44, 50, 55 and is shown in Fig. 9, the components having the same references as in the other Figures. The battery 28, in the form of a disc, is accommodated in a compartment at the end of the bow and can be removed after turning a cap 29 about a pivot 31. The cap is locked in its closed position by a spring detent 32 which is released by pushing a wire through a hole 35. The receiver 41 and the microphone 40 are mounted in foam rubber jackets 47 and have their axes at right-angles so as to avoid acoustic reaction. The receiver 41 is fitted with a flexible ear tube 45 carrying an ear plug 46 of foam rubber. A combined on/off switch and volume control 38 is accommodated in a cylindrical body 38b and is controlled by a rotatable element 38w which projects through a slot 39 in the bow. Sound has access to the microphone through a small hole 40c in the lid of the bow. Apart from the microphone and the receiver, the components are cemented in position in the container x. The lid y is secured to the container by screws 25. The wiring is shown in Fig. 9 only. The receiver may be formed in the ear plug and is then connected to the bow by wires. If the receiver is a bone conduction receiver, the microphone, receiver and volume control shown in Fig. 4 are rearranged so that the receiver and the microphone replace 38 and 41 of Fig. 4, their axes being maintained at right-angles.