Shock insensitive transducer

Claim 2

A microphone having a frequency response range comprising a hollow casing having an opening at one end thereof, a transducer disposed within the casing having a housing with a cavity therein and an orifice extending from the cavity to the exterior of the housing, said transducer having a diaphargm acoustically sealed about the orifice in the housing with an exterior side confronting the opening in the casing and an interior side, means including the housing and the diaphragm forming a diaphragm chamber on the interior side of the diaphragm, compliant support means for mounting the housing on the casing for translation with respect to the casing including a compliant member mounted on the casing and on the confronting surface of the housing, the effective mass of the transducer and the compliance of the support means forming a mechanical resonance at a frequency below the response range of the microphone, the housing including means defining a variable volume cavity and a passageway acoustically coupling the cavity with the diaphragm chamber, a force resolving coupling mounted between the casing and the means defining the variable volume cavity for transmitting only the component of accelerations impressed on the casing normal to the diaphragm and to the variable volume cavity defining means, the volume of the variable volume cavity changing in the same directIon as the diaphragm chamber responsive to forces impressed upon the casing to produce a pressure change in the variable volume cavity which is transmitted through the passageway to oppose the change in volume of the diaphragm chamber.

Claim 3

A microphone comprising the combination of claim 1 wherein the means defining the variable volume cavity includes a flexible wall in the form of a second diaphragm disposed generally parallel to the aforesaid first diaphragm, said second diaphragm being mechanically coupled to the casing.

Claim 4

A microphone comprising the combination of claim 2 wherein the second diaphragm is disposed on the opposite side of the housing from the first diaphragm and constructed of compliant material, said second diaphragm being coupled to the casing by a rigid pin affixed to the casing at one end and the diaphragm at the other end.

Claim 5

A microphone comprising the combination of claim 3 wherein the coupling means for transmitting the component of accelerations impressed on the casing normal to the diaphragm to the flexible wall comprises a compliant ring mounted about the housing and on the casing, said ring being disposed in a plane parallel to the first and second diaphragms and between the first and second diaphragms.

Claim 6

A microphone comprising the combination of claim 1 wherein the passageway acoustically coupling the cavity with the diaphragm chamber contains means for reducing pressures transmitted from the variable volume cavity to the diaphragm chamber.

Claim 7

A microphone comprising the combination of claim 5 wherein the means for reducing pressures comprises an elongated channel in the passageway of a diameter less than the cross section of the cavity.

Claim 8

A microphone comprising the combination of claim 6 wherein the means for reducing pressures comprises a second cavity in the passageway with a cross section greater than the elongated channel.

Claim 9

A microphone comprising the combination of claim 5 wherein the means for reducing pressures comprises a mass of porous material disposed in the passageway.

Claim 10

A microphone comprising the combination of claim 5 wherein the transducer comprises a voice coil mounted on the diaphragm and a magnetic structure forming a gap accommodating the voice coil and a magnet, the passageway including the gap in the magnetic structure.

Claim 11

A microphone having a frequency response range comprising a hollow tubular casing closed at one end and having an aperture at the opposite end thereof, a transducer having a housing with a cavity therein and an orifice extending from the cavity to the exterior of the housing, said transducer having a diaphragm acoustically sealed about the orifice in the housing with an exterior side confronting the opening in the casing and an interior side, the interior side of said diaphragm being one wall of a diaphragm chamber, an air impermeable shell rigidly secured to the hollow tubular casing, said shell having a recess extending therein from an orifice, the housing of the transducer being disposed within the recess of the shell and extending from the orifice thereof and exposing the diaphragm, said housing only partially filling the recess of the shell and forming a chamber between the housing and the shell, compliant support means for mounting the housing on the shell for translation with respect to the shell only along the axis of elongation of the casing including a compliant member mounted on the shell and on the confronting surface of the housing, said compliant member extending about the orifice and of the shell and sealing the orifice of the shell on the housing to acoustically seal the chamber within the shell from the exterior of the shell, the effective mass of the transducer and the compliance of the support means forming a mechanical resonance at a frequency below the response range of the microphone, said housing having an aperture extending therethrough on the side of the housing opposite the orifice and said aperture communicating at one end thereof with a recess in the housing of the transducer opening into the chamber within the shell and at the other end thereof with the diaphragm chamber of the transducer, a compliant membrane extending over the recess and acoustically sealed on the housing about the recess to form a cavity, and a rigid anchor mounted on the shell and affixed centrally of the membrane, whereby a mechanical shock or vibration in the frequency response range of the microphone impressed upon the casing translates the housing with respect to the shell to change the volume of the cavity, thus altering the pressure on the interior side of the diaphragm to oppose shock or vibration induced changes in the position of the diaphragm due to inertia.

Claim 12

A microphone having a frequency response range comprising a hollow tubular casing closed at one end and having an aperture at the opposite end thereof, a transducer having a housing with a cavity therein and an orifice extending from the cavity to the exterior of the housing, said transducer having a diaphragm acoustically sealed about the orifice in the housing with an exterior side confronting the opening in the casing and an interior side, the interior side of said diaphragm being one wall of a diaphragm chamber, an air impermeable shell rigidly secured to the hollow tubular casing, said shell having a recess extending therein from an orifice, the housing of the transducer being disposed within the recess of the shell and extending from the orifice thereof and exposing the diaphragm, said housing only partially filling the recess of the shell and forming a chamber between the housing and the shell, compliant support means for mounting the housing on the shell for translation with respect to the shell only along the axis of elongation of the casing including a compliant member mounted on the shell and on the confronting surface of the housing, said compliant member extending about the orifice and of the shell and sealing the orifice of the shell on the housing to acoustically seal the chamber within the shell from the exterior of the shell, the effective mass of the transducer and the compliance of the support means forming a mechanical resonance at a frequency below the response range of the microphone, said housing having an aperture extending therethrough on the side of the housing opposite the orifice and said aperture communicating at one end thereof with a recess in the housing of the transducer opening into the chamber within the shell and at the other end thereof with the diaphragm chamber of the transducer, a compliant membrane extending over the recess and acoustically sealed on the housing about the recess to form a cavity, and a rigid anchor mounted on the shell and affixed centrally of the membrane, whereby a mechanical shock or vibration in the frequency response range of the microphone impressed upon the casing translates the housing with respect to the shell to change the volume of the cavity, thus altering the pressure on the interior side of the diaphragm to oppose shock or vibration induced changes in the position of the diaphragm due to inertia.