Abstract: In a battery receiving chamber, the first convex part is formed in the internal side face of the battery compartment and the second convex part which corresponds to the first convex part is formed in the battery cover, the first and second convex part respectively having the inclined faces which gradually rise toward the rotational direction in which the battery cover is detached from the battery compartment, so that a battery receiving chamber having good usage convenience and highly reliable can be realized. Further, in a hearing aid using the above, waterproof means is located so as to block the air vent formed in the battery cover, and a slot connecting the end part of battery cover and the air vent in the external side face of the battery cover is comprised, so that a hearing aid which can supply practically sufficient volume of air into the case and has high waterproof performance can be realized.

Abstract: A hand-held vibrometer for measuring vibration at a surface of a vibrating object includes plural vibration sensors, each of which has a respective axis of measurement. The vibration sensors are mounted on a rigid body so that the respective axes of measurement of the sensors intersect at a contact point on the rigid body, which contact point is to be applied to the vibrating object. The contact point is at a central axis of the rigid body and the respective axes of measurement of the vibration sensors all intersect the central axis of the rigid body at the same angle. Respective amounts of vibration in the vibrating object in three orthogonal measurement axes are calculated on the basis of output signals provided from the plurality of vibration sensors. The above-described arrangement of the vibration sensors increases the contact resonance frequency, and consequently the measurement range, of the vibrometer.

Abstract: In an output circuit for pulse width modulation of an input signal and output of it to a predetermined vibrating section, power consumption is remarkably reduced with a comparatively simple configuration.

Abstract: A hearing aid is used to be inserted into and removed from an ear hole. A cam attached to a taking-out knob pushes up a battery holder by lifting up the taking-out knob when the hearing aid is taken out from an ear hole, whereby the electrode of the battery in the battery holder is left from the battery connecting tongues attached to a panel portion to thereby turn OFF a power supply. A howling prevention fixture is fixed to a hearing aid case at the head portion thereof to prevent howling.

Abstract: A receiving chamber for an air cell battery for use in an electronic device having a casing 2 in which a battery receiving chamber 11 having an open upper end is defined by a wall portion thereof comprises a cover member 13 for selectively closing the open end of the battery receiving chamber, a through-hole 31; 41 formed in the battery receiving chamber for communicating the battery receiving chamber externally, and filter means 32 provided in the through-hole for repelling the water content of air supplied through the through-hole to the battery receiving chamber while allowing air to pass through.

Abstract: An audio current pick-up device for use with an electric wire 6 carrying an electric current containing audio information comprises a pair of substantially identical magnetic induction coil assemblies 26, 27 disposed in parallel to each other with an axial deviation and orthogonally to the wire, each coil means including a magnetic core in the form of rod 30, 38 and a pair of induction coils 32A, 32B, 39A, 39B wound in opposite directions on respective halves of its core rod. An output of either of the induction coils is phase-shifted by a preset amount and composited with an output of the other magnetic induction coil to form a sound pick-up signal from which a sound output signal is derived.

Abstract: A hearing aid having a comparator or comparators which compare speech sound signals obtained by a first transducer with reference voltage(s) as slice level(s) formed from a standard voltage and which output time series square wave containing frequency information according to the relations of amplitude between the speech sound signals and the slice level(s).The time series square wave is output as mechanical vibrations, which is easy to adjust the level for hearing impaired persons having a narrow dynamic range.Comparators may be provided for both positive and negative sides and may be divided into plural numbers in order to raise the identification score and information content.

Abstract: A method of measuring the degree of nasality in human voice sounds by independently isolating and measuring without leakage the exhaled air flow rate through the nose and the exhaled air flow rate through the mouth of a person resulting from the utterance of a sound and determining the ratio of the two air flow rates.

Abstract: A hearing aid is made up of an automatic filter circuit for transmitting an input signal in a predetermined characteristic, and a low frequency component detecting circuit for detecting the low frequency component of the input signal, to change the characteristic of the automatic filter circuit according to the detection level, the cut-off frequency of the automatic filter circuit being changed according to the output control signal of the low frequency component detecting circuit.

Abstract: The invention relates to an electromagnetic induction coil or antenna device embedded in hearing aids or radio sets for receiving sound signals or carrier signals generated by a primary electromagnetic induction coil which is laid down in the room. A plurality of coils each one end of which is commonly connected and each other end of which extends outwardly from the one end so as to be uniformly arranged in a space and a phase selector connected to the coils operates, as a mercury switch, to pick up positive phase component output signals which are induced in at least any of the coils. The coils and the phase selector are fixedly built in the body of a hearing aid, etc. so that the corresponding coil and conduit in which a suitable quantity of mercury is charged may be paralleled to each other and so on, thereby to obtain a constant output sound pressure irrespective of the posture of a person wearing a hearing aid or enjoying television.

Abstract: In a hearing aid, when the input sound pressure to the microphone exceeds a preset level for a preset period of time, a control signal is produced to automatically decrease the maximum output sound level, thereby decreasing the overload to the user.

Abstract: A behind-the-ear type hearing aid which includes a main body adapted to hang on the user's earlobe on the rear side, an opening disposed at the front end of the main body to communicate with a microphone used for normal conversation, and a pair openings disposed on its rear end portion to communicate with a closed talking microphone for use with telephone conversations disposed in the main body. The close talking microphone may be connected to a low-pass filter with a cutoff frequency of about 1,000 hertz. The close talking microphone may also include two pressure type microphones which are substantially identical in sensitivity and are disposed adjacent to each other. One of those microphones has an output connected to that of the other microphone through a phase inverter with or without a gain control connected across the phase inverter.

Abstract: A hearing aid appliance has induction loops which are magnetically coupled to hearing aids held individually by hard-of-hearing persons. The number of induction loops is an integral multiple of two, and each induction loop is in the form of a rectangle having at least two parallel sides. The parallel sides of the induction loops are arranged in parallel with one another and equally spaced from one another so that signal currents flowing in adjacent parallel sides are shifted by 90.degree. in phase.

Abstract: A sensing coil unit for a hearing aid is made up of a sensing coil which is in the form of a cylinder one end of which is heavier than the other end and is floated in the liquid in a sealed container, so that the sensing coil is vertical at all times irrespective of the positions of the hearing aid thereby to maintain constant its magnetic coupling condition with the inductance coil which is laid to transmit voice signals to the sensing coil.