Microphone for the transmission of body sounds
First Claim
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1. A microphone for the reception and conversion of low frequency sound, especially body sound signals, which can be used advantageously in conjunction with blood pressure measuring devices and the like, the microphone comprising in combination:
- a cup-shaped microphone housing having a bottom and a generally tubular side wall with a rim defining an open upper end of the housing;
a circular membrane covering the open end of the housing and having a narrow peripheral edge portion clamped against the rim of the side wall;
a substantially flat flexural piezoelectric transducing wafer arranged inside the housing;
means for mounting the transducing wafer above the housing bottom, a distance from the membrane, and in substantially parallel alignment with the latter, the mounting means holding the transducing wafer in a cantilever fashion so as to allowing a portion thereof to flex freely in displacement alignment with the center of the membrane; and
a resiliently compressible transmitter body interposed between and engaging both the membrane and said flexing portion of the wafer, at least a portion of the transmitter body, including the extremity with which it is engaged against the wafer, being of a cellular, foamed material suited for the transmission of low frequency sound vibrations.
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Abstract
A microphone for the transmission and conversion of low frequency body sound signals, characteristic of blood pressure conditions, the microphone featuring a Seignette salt crystal wafer as a transducing element, a foamed body as a transmitting element, a vibrating mass on the microphone membrane, and a deflection-limiting safety plate. The membrane carries a contact-focusing touch plate, and the entire housing is enveloped in a sound insulating rubber jacket.
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Citations
31 Claims
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1. A microphone for the reception and conversion of low frequency sound, especially body sound signals, which can be used advantageously in conjunction with blood pressure measuring devices and the like, the microphone comprising in combination:
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a cup-shaped microphone housing having a bottom and a generally tubular side wall with a rim defining an open upper end of the housing; a circular membrane covering the open end of the housing and having a narrow peripheral edge portion clamped against the rim of the side wall; a substantially flat flexural piezoelectric transducing wafer arranged inside the housing; means for mounting the transducing wafer above the housing bottom, a distance from the membrane, and in substantially parallel alignment with the latter, the mounting means holding the transducing wafer in a cantilever fashion so as to allowing a portion thereof to flex freely in displacement alignment with the center of the membrane; and a resiliently compressible transmitter body interposed between and engaging both the membrane and said flexing portion of the wafer, at least a portion of the transmitter body, including the extremity with which it is engaged against the wafer, being of a cellular, foamed material suited for the transmission of low frequency sound vibrations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 13, 14, 15, 16, 17, 20, 21, 22, 25, 26)
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12. and 0.8 mm. 14. A low frequency microphone as defined in claim 12, wherein
the microphone housing includes a shoulder on the inner side of the housing side wall; - and
the safety plate rests on said shoulder and is held in place by the housing - View Dependent Claims (10, 11)
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19. outline, when clamped therebetween. 21. A low frequency microphone as defined in claim 19, wherein
the clamping collar and the housing rim have aligned oppositely facing circular knife edge profiles with which they bear against the peripheral edge portion of the membrane, thereby creating said clamping engagement.
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24. RTV, Part No. KTR-2264 028 143 and curing agent TK, Part No. KTR-801. 26. A low frequency microphone as defined in claim 24 wherein
the shape of the touch plate approximates that of a sector of a body of
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28. name Elastosil 59. 30. A low frequency microphone as defined in claim 28, wherein
the jacket is a cup-shaped body of polyamide, enveloping the bottom and side wall of the microphone housing;
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31. of rotation having an arched generatrix. 33. A low frequency microphone as defined in claim 32, wherein
the outline of said jacket portion approximates the curvature of a sector of a minor-axis ellipsoid, cut along a plane parallel to its rotational axis.
Specification