US3602653A

US3602653A - Electroacoustic transducer mount

Info

Publication number: US3602653A
Application number: US746661A
Authority: US
Inventors: Wilmer H Schaumberg; Wolfgang W Jensen
Original assignee: Pacific Plantronics Inc
Current assignee: Plantronics Inc; Pacific Plantronics Inc
Priority date: 1968-07-22
Filing date: 1968-07-22
Publication date: 1971-08-31
Anticipated expiration: 1988-08-31

Abstract

Acoustical apparatus is disclosed including microphone and receiver transducers mounted together within a supporting enclosure. Support means are disposed intermediate the transducers and enclosure to eliminate vibrational couplings inbetween the transducers. The support means includes a plurality of resilient support members between the transducers and enclosure and in substantially line contact with the enclosure, with the support members having a cross section which increases in area from said contact in the direction from the enclosure toward the respective transducer. A resilient element integral with the support members includes integral resilient bumper means normally spaced out of contact with the enclosure for providing additional supporting force for the transducers only in response to the movement thereof relative to the enclosure by a selected amount.

Description

gether pport members spective gral with the support memper means normall sposed innate vibrain substantially pport members aving a cross section which increases in area from said cony spaced g additional supsponse to the moveselected amount.

3,118,023 l/l964 Victoreen..................... r z, 3,172,963 3/1965 Victoreen.............;....... 3,184,556 5/1965 Larkin.................,........ 3,280,273 /1966 Flygstad et al. 3,446,341 5/1969 Kutik.........

Primary Examiner-Kathleen H. Claffy Assislant Examiner Randall P. Myers I "Attorney-Elem, Hohbach, Test, Albritton & Herbert ABSTRACT: Acoustical apparatus is disclosed includin microphone and receiver transducers mounted to within a supporting enclosure. Support means are di 179/179, termediate the transducers and enclosure to elimi l79/156 tional couplings in-between the transducers. The su H041" 1/041 means includes a plurality of resilient su H04!" between the transducers and enclosure and line contact with the enclosure, with the su 156, 179, 180, 100 R, 107 S; 248/15, 22, 358, 24; h

i 352; 206/46 FR; tact in the direction from the enclosure toward the re 17 /5034, 50, 2 transducer. A resilient element inte bers includes integral resilient burn out of contact with the enclosure for providin porting force for the transducers only in re 179/179 ment thereof relative to the enclosure by a Wolfgang W. Jensen, both of Santa C Calif. Appl. No. 746,661

July 22, 1968 Patented Aug. 31, 1971 Pacific Plantronics, Inc. Santa Cruz, Calif.

References Cited UNITED STATES PATENTS 3,048,668 8/1962 ELECTROACOUSTIC TRANSDUCER MOUNT 6 Claims, 3 Drawing Figs.

Field of United States Patent [72] inventors WilmerR'Schaumber-g;

[22] Filed [73] Assignee [51] Int.Cl....................;....

PATENTED AUB31 lsn INVENTORS WILMER H. SCHAUMBERG WOLFGANG W. JENSEN ATTORNEY ELECTROACOUSTIC TRANSDUCER MOUNT BACKGROUND OF THE INVENTION Certain miniature telephone headsets include microphone and receiver transducers mounted in a common enclosure with a first acoustic tube attached to the microphone transducer for acoustically coupling the users voice to the microphone from a remote location and with a second acoustic tube attached to the receiver transducer to couple acoustic energy therefrom to the users ear canal. In this way the enclosure may be mounted about the users head away from his face, mouth and ear for uninhibited head movement and for comfort and convenience. However, the close proximity of the receiver ad microphone transducers within a miniature enclosure commonly produces acoustic energy feedback paths between the transducers that can create undesirable instabilities in the overall system where external circuit gains exceed the acoustic isolation between transducers.

SUMMARY OF THE INVENTION Accordingly, the present invention provides mounting and isolating means for microphone and receiver transducers disposed within a common miniature enclosure which provide extremely high acoustic energy attenuation between transducers while supplying adequate mechanical rigidity to retain the transducers in situ even under shock-loading conditions. Resilient material interposed between the transducers and the enclosure is shaped to contact the enclosure only at point of negligible cross-sectional area, thereby introducing only a negligible acoustic'energy conduction path between transducers through the enclosure. Under shock-loading conditions, the contact pointsflatten out to larger contact area, thereby producing increasing resilient force to retain the transducers in position within the enclosure. Also, inlet and outlet ports through the enclosure respectively to the microphone and receiver transducers are isolated from the enclosure to eliminate acoustic-energy feedback paths between transducers through the enclosure.

DESCRIPTION OF THE DRAWING FIG. 1 is a sectional view of a miniature headset assembly showing the microphone and receiver transducers mounted within a common enclosure;

FIG. 2 is a side view of the microphone transducer of FIG. 1 showing the mounting means about the transducer; and

FIG. 3 is a perspective view showing the general shape of the resilient mounting means for the transducers of FIG. 1.

PREFERRED EMBODIMENT OF THE INVENTION Referring now to FIG. 1, there is shown an enclosure 9 within which the microphone transducer 11 ad receiver transducer 13 are mounted. Each of the transducers 11 and 13 is surrounded on its edges and partially over its faces near the periphery thereof by a unitary resilient boot 15, 16, as shown in FIGS. 2 and 3. The resilient boot 15 for the microphone transducer 11 difiers from the resilient boot 16 for the receiver transducer 13 only in that one set of comer mounting surface (lower right of 16) are displaced along the horizontal and vertical edges of the boot 16 to accommodate the acoustic outlet port 17 of the transducer. The resilient boot 15 for the microphone transducer 11 does not require such modification because the acoustic inlet port 29 is disposed normal to, and about in the middle of. the lower edge of transducer 11.

Each of the resilient boots l5, 16 includes a plurality of longitudinal support elements 19 disposed near the corners of the transducers which support the associated transducer within the enclosure 9 along the thickness dimension of the transducer. These support elements 19 taper to a contact edge 20 and the dimensions of the resilient boot 15, 16 between the contact edges of those support elements 19 are selected relative to the dimensions of the mating surfaces within the enclosure 9 to provide mere point (or line) contact with the enclosure of negligible cross-sectional area. Also, each resilient boot 15, 16 includes surface support elements 21 disposed near the corners of the boot on both major surfaces thereof to provide support for the associated transducers in a direction normal to such major surfaces. Each of these surface support elements 21 tapers to a ridge 23 of negligible area which is disposed to contact the mating surface within the enclosure 9. Thus, the associated transducer is supported within the enclosure 9 by the contact edges of negligible area of the

support elements

19 and 21 and is constrained against movement in the six degrees of freedom. This extremely small supporting cross-sectional area of resilient material thus provides high acoustic attenuation or isolation between the associated transducer and the enclosure 9. The supporting

elements

19 and 21 have divergently tapering cross sections in the direction toward the transducer along the normal to the contact area of the

support element

19, 21 in order to provide a nonlinearly increasing resilient restoring force as the contact edge of a supporting

element

19, 21 is flattened or distorted under shock-loading conditions. This assures maximum acoustic isolation or attenuation between transducer 11, 13 and enclosure 9 consistent with mechanical support of the transducer in normal use of the assembly and minimum shock susceptibility under severe conditions of high acceleration along any axis due, for example, to dropping or bumping of the assembly. Also, a discontinuity in the resilient restoring force provided by the resilient boot 15, 16 in the direction normal to the major surface may be provided by including integral bumper elements 25 near the periphery of be major surfaces and between the comers thereof. These bumpers elements do not contact the enclosure in normal use and hence do not contribute any acoustic energy conduction paths between the enclosure 9 and the associated transducer 15, 16. However, under high shock-loading conditions, if the surface support elements 21 distort or flatten out sufficiently, then the bumper elements 25 engage the enclosure and introduce a discontinuous increase in resilient restoring force as a function of displacement of the associated transducer from its normal posi tion within the enclosure 9. In practice, the resilient boot is molded of low durometer neoprene rubber which exhibits a small resilient restoring force.

High acoustic isolation or attenuation between transducer 11, 13 and the enclosure 9 provided by the resilient boots 15, 16 is preserved in accordance with the present' invention despite the fact that the acoustic inlet and outlet ports must pass through the enclosure 9 and be mounted thereon for mechanical rigidity. The inlet port 29 of microphone transducer 11 and the outlet port 17 of receiver transducer 13 receive thin-walled resilient tubes 31, 33 that communicates with the inlet and outlet pipes or ports 35, 37 respectively, of the assembly which are rigidly secured to the enclosure 9. This provides mechanical rigidity of the pipes or ports 35, 37 with respect to the enclosure and eliminates exertion of stresses on the transducers during rough handling and also isolates the transducers from mechanical vibrations impressed upon the pipes or ports 35, 37 from the exterior environment. The thinwalled resilient tubes 31, 33 thus couple acoustic signals between the pipes or ports 35, 37 and the associated transducer 11, 13 but introduce only negligible acoustic energy transmission paths between the enclosure 9 and the transducers. An acoustic coupling tube 39 attached to the inlet pipe or port 35 is, in turn, isolated from the pipe 35 by resilient insert 41 which isolates mechanical vibrations on the acoustic tube 39 from the enclosure 9 and the transducers ll. 13 therewithin. At the same time, the insert 41 provides good coupling between the acoustic tube 39 and the transducer 11 for acoustic signals within the acoustic tube 39. A circumferential protrusion on pipe 35 and a mating depression in the resilient insert 41 within an acoustic tube 39 provides a longitudinal detent for retaining the acoustic tube 39 in longitudinal position on the inlet pipe 35 while allowing the acoustic tube 39 to rotate about the inlet pipe 35. A similar rotatable acoustic coupling joint may be provided on the outlet pipe 37 where desired.

The electrical conductors 43 for connecting the transducers to external circuitry are bundled or cabled together and are rigidly attached to the enclosure 9 for mechanical rigidity. However, the individual conductors have thin cross sections and are looped or bent substantially as shown at locations therealong intermediate the transducers ll, 13 and the mounting on the enclosure 9 to ensure that only negligible acoustic energy transmission paths are introduced between the enclosure 9 and the transducer 11, 13.

Therefore, the present invention substantially eliminates the acoustic-energy transmission paths between transducers and between a transducer and the enclosure 9; thereby providing improved acoustic isolation of the transducers from each other and from the surrounding environment. I

We claim:

1. Acoustic apparatus comprising:

acoustic transducer means and a supporting enclosure therefor; and

support means disposed intermediate said acoustic transducer means and said enclosure and including a plurality of resilient support members between said transducer means and the enclosure, the support members being in substantially line contact with the enclosure and said support members having a cross section which increases in area from said contact in the direction from the enclosure toward the transducer means in a selected static position relative to said enclosure, said support means including integral resilient bumper means disposed about a selected region of the transducer means and spaced out of contact with said enclosure a given distance for providing additional supporting force for said transducer means only in response to the movement thereof through said distance relative to the enclosure from said static position.

2. Apparatus has in claim 1 wherein said support members and bumper members are integral portions of a resilient element disposed about said transducer means.

3. Apparatus as in claim 2 wherein said transducer means includes a pair of spaced major faces and a peripheral edge substantially normal to a major face; and

said resilient support members are spaced near said peripheral edge to provide resilient supporting forces for said transducer means relativeto said enclosure in directions substantially normal to said peripheral edge and to said major faces. I

4. Apparatus as in claim 1 wherein said transducer means includes an acoustic signal port;

an acoustic signal pipe supported on said enclosure; and

a flexible acoustic tube acoustically coupling said acoustic signal port of said transducer means to said acoustic signal pipe supported on said enclosure.

5. Apparatus as in claim 4 including an acoustic coupling tube of substantially rigid form having a coupling end and a remote end, said coupling end being disposed over said acoustic coupling pipe; and

a resilient insert disposed intermediate said acoustic signal pipe and said coupling end of the acoustic coupling tube for acoustically isolating the acoustic signal pipe from vibrations on said acoustic coupling tube.

6. Apparatus as in claim 5 wherein said acoustic signal pipe is substantially cylindrical and includes a radially outwardly extending protrusion at a selected location along the length thereof; and

said resilient insert includes an annular depression positioned along an inner surface thereof for mating with said protrusion to provide a longitudinal detent for permitting relative rotational movement in substantially fixed longitudinal position of said acoustic coupling tube with respect to the acoustic signal pipe.

Claims

1. Acoustic apparatus comprising: acoustic transducer means and a supporting enclosure therefor; and support means disposed intermediate said acoustic transducer means and said enclosure and including a plurality of resilient support members between said transducer means and the enclosure, the support members being in substantially line contact with the enclosure and said support members having a cross section which increases in area from said contact in the direction from the enclosure toward the transducer means in a selected static position relative to said enclosure, said support means including integral resilient bumper means disposed about a selected region of the transducer means and spaced out of contact with said enclosure a given distance for providing additional supporting force for said transducer means only in response to the movement thereof through said distance relative to the enclosure from said static position.

3. Apparatus as in claim 2 wherein said transducer means includes a pair of spaced major faces and a peripheral edge substantially normal to a major face; and said resilient support members are sPaced near said peripheral edge to provide resilient supporting forces for said transducer means relative to said enclosure in directions substantially normal to said peripheral edge and to said major faces.

4. Apparatus as in claim 1 wherein said transducer means includes an acoustic signal port; an acoustic signal pipe supported on said enclosure; and a flexible acoustic tube acoustically coupling said acoustic signal port of said transducer means to said acoustic signal pipe supported on said enclosure.

5. Apparatus as in claim 4 including an acoustic coupling tube of substantially rigid form having a coupling end and a remote end, said coupling end being disposed over said acoustic coupling pipe; and a resilient insert disposed intermediate said acoustic signal pipe and said coupling end of the acoustic coupling tube for acoustically isolating the acoustic signal pipe from vibrations on said acoustic coupling tube.

6. Apparatus as in claim 5 wherein said acoustic signal pipe is substantially cylindrical and includes a radially outwardly extending protrusion at a selected location along the length thereof; and said resilient insert includes an annular depression positioned along an inner surface thereof for mating with said protrusion to provide a longitudinal detent for permitting relative rotational movement in substantially fixed longitudinal position of said acoustic coupling tube with respect to the acoustic signal pipe.