BONE-CONDUCTION HEARING-AID V

Patented Mar. 28. 1938

2,151,70s

This invention relates to wearable bone conduction hearing aids and it has among its objects a bone conduction hearing aid utilizing ft strip of flexible self-aligning material held * stretched along the bony lower rear portion of the head of the user for pressing the vibration imparting contact surface of a bone conduction receiver against the bones of the head and inducing hearing by bone conduction under elimi10 nation of the discomfort caused by stiff head bands clamped around the head for pressing the receiver against the bones of the head.

The foregoing and other objects of the invention will be best understood from the following 15 description of exemplifications thereof, reference being had to the accompanying drawings, wherein—

Kg. 1 is a perspective view showing a bone conduction receiver worn on the head of a person 20 in accordance with the invention, and a diagram of the operating circuit of the receiver;

Pig. 2 is a view of the receiver with its supporting elements;

Fig. 3 is an enlarged sectional view of the 25 receiver along lines 3—3 of Fig. 5;

Fig. 4 is a top view of the receiver; Fig. 5 is a vertical sectional view of the receiver;

Pig. 6 is a detailed enlarged view of an ear SO clasp of the receiver support;

Pig. 7 is a< view similar to Pig. 2 of a modified receiver support;

Pig. 8 is a top view of the support shown in Pig. 7;

35 Pig. 9 is a view of the receiver with its support illustrating a further modification of the inven• tlon; .

Fig. 10 is a top view of the support shown in Fig. 9; .

46 Hg. 11 is a perspective view illustrating a modified receiver support of the invention;

Fig. 12 is E top view of one of the arrange. snents shown in Pig. 11;

Fig. 13 is a vie?/ similar to Fig. 12 showing a 4S further modification of the invention; and

Pig. 14 is a view similar to Pig. 7 illustrating a still further modification of the invention.

Bef erring to the exemplification of the invention shown in Figs. 1 to 6, it comprises a bone SO conduction receiver, of the type disclosed in Greibach Patent 2,127,468, in the form of a small vibratory casing 20 having actuating windings 21 which are connected to a supply circuit formed of a transmitter 22 connected in series with a 65 supply battery 23 to the actuating coil 24 of an

amplifier microphone 25 which is connected is series with the battery 23 to the leads 25 which supply the current to the actuating windings 2 i of the receiver, all constructed for inconspicuous wear by the user. Under the action of the sup- & plied electric sound frequency oscillations, the floating part of the vibratory structure 21 imparts through its inertia reaction hearing inducing vibratory forces to the casing 20, and by way of its contact wall 28 to the hearing inducing 1C bones 29 of the user for inducing hearing by bone conduction.

As shown to Pigs. 1 to 4, the vibratory surface of the receiver casing 20 is held coupled to the mastoid bone 29 of the user, behind the ear, by 15 supporting arrangements comprising a pair of ear clasps 31, 32 and a strip 33 of self-aligning flexible material, such as rubber fabric, which are interconnected with the receiver 20 so as 'to hold a contact surface 28 of the receiver 20 20 against the mastoid bone.

As shown in Pig. 1, the flexible self-aligning supporting .strip 33 extends over the occipital bone of the head below the greater occipital protuberance and the clasps 31, 32 which hold the 25 strip 33 in the stretched condition engage por^ tions of the head at the junction of the auricle to the head in the region of the temporal bones. Such arrangement of the stretched strip and its stretching means which hold it in stretched con- 30 dition make it possible to retain the stretched strip 33 in a self-aligning position on the lower region of the back of the head in which it is able to exert on the bone conduction receiver the. pressure required for transmitting to the bones 35 hearing inducing vibrations without discomfort to the user.

The ear clasp 31 is made in the form of an oval wirelike member shaped to fit the groove along the rear side of the junction of the auricle 40 to the head. The clasp 31 is retained in its place on the ear by front portions 37 overlapping the junction portions of the auricle to the head so as to firmly and yet gently support the clasp it on the ear and prevent its being pulled off the 45 ear by rearwardly directed forces acting on the intermediate portion of the clasp 31. The center portion of the clasp 31 has a pin shaped projection 35 fitting into a.longitudinal channel member 36 provided along one edge of the vi- 50 bratory receiver casing 20 for holding the receiver. The other side of the receiver casing 20 has an eyelet 41 to which is tied one end of the self-aligning supporting strip 33 the other end of which is held to an eyelet 40 formed on the u center portion -of 2:e similar other ear clasp 12 which engages the other ear.

The supporting strip It may be of rubber or similar resilient material, covered with a woven fabric, such as silk, and is arranged to lie snugly in stretched condition against the head, hidden under the hair, as shown in Fig. 1. The length of the supporting strip 31 Is so proportioned that when It is held stretched by the ear clasps II, It, the contact surface 28 of the receiver casing 21 will be held against the bones 29 with the pressure required for securing efficient transmission of the hearing inducing vibrations from the contact wall 21 of the receiver casing 20 to the bone structure.

The end portions of the ear clasps II, 12 may be made of a resilient metal wire as shown In Fig. 6 and comprise several layers 41, 44, 45 of wire strands closely wound over the wire of the clasp, in a way similar to temple Wires of spectacle frames, so as to secure a good gripping connection between the clasp ends and the engaged auricle portions and permit easy adjustment of the clasp to the shape of the auricle. The clasps II, 12 may be made of any suitable metal and the ends overlapping the auricle and resting against It may be provided with a resilient layer 41 of rubber or like material to distribute the pressure over the contact surface. The resilient engagement of the clasp pin IB with the receiver channel II Is so arranged as to assure alignment of the receiver relatively to the surface of the bones and good coupling engagement therebetween.

By utilizing a strip of flexible self -aligning fabric material which is held stretched over the rear of the head, below its greater occipital protuberance, by clasp means which engage the portions of the head in the region of the temporal bones so as to exert on the receiver casing forces which hold It in Intimate vibration transmitting contact engagement with the bones of the head, the receiver support win be automatically retained In a self -aligning vibration transmitting position and assure efficient transmission of the hearing inducing vibrations to the bones of the head.

In Figs. 7 and 8 is shown a modified bone receiver supporting arrangement. It comprises a relatively rigid, slightly flexible, U-shaped supporting frame member II having Inward protuberances 12 engaging suitable depressions in the side walls of the receiver casing. One of. the arms of the frame II Is provided with a longl* tudlnal eyelet II which is engaged by the central portion of an ear clasp II similar to the ear clasp of Fig. 2. The other arm of the receiver supporting frame II is provided with an eyelet 84 to which Is tied one end of a flexible self-aligning supporting strip 11, the other end of which Is tied to the other similar ear clasp 12 so as to support the receiver frame II in a position in .which It presses the contact surface of the receiver casing against the hearing inducing bones. The clasp 1 1 Is reslllently mounted within the channel member II of the receiver frame 51 so as to be free to turn and provide a self -adjustable support for the receiver casing. The pivotal mounting of the receiver casing on the pivot phis 12 of the receiver frame II assures automatic alignment of the contact surface of the receiver 21 against the bones.

As shown in Fig; 8, the vibratory receiver casing 21 is provided with a channel 16 for receiving the end of a head band so as to enable the user

to wear the receiver either with the stretchable strip support arrangement shown In the drawings or by means of a steel head band clamped over the head. The frame II has sufficient resiliency to permit spreading apart of Its arms and removal of the receiver 20 from Its supporting pin 12.

In Figs. 9 and 10 is shown a bone receiver supporting arrangement similar to that of Figs. 7 and 8, but using a different form of U-shaped receiver supporting frame II arranged to embrace one of the narrow end walls of the receiver.

In Figs. 11 and 12 Is shown another form of bone receiver support by a flexible self-aligning fabric strip 11. The receiver is plvotally mounted on a frame II as In the arrangement of Fig. 7. The channel-shaped eyelet II of the frame is engaged by an end portion of a modified form of clasp 1 1 formed of metal or similar material and arranged to embrace only the upper junction of the auricle to the head. The clasp 1 1 comprises a front arm 12 and a rear arm 63 embracing the upper portion of the auricle edge adjacent Its junction to the head, the front end 14 of the clasp being bent to fit into the cavity behind the upper helix portion IB of the auricle. The rear part of the clasp 1 1 extends along the rear portion of the auricle and terminates in a pivotal pin portion held In the channel member II provided on one arm of the receiver supporting frame II. The two ends of the stretched sup'portlng strip It extending along the back of the head are joined to the eyelet 14 of the receiver supporting frame, and to an eyelet IT provided on the rear end of a clasp II shaped similarly to the clasp II, and engaging the auricle of the other ear, so as to secure self-aligning support of the receiver in contact with the bones of the head. . '; i ; i

In Fig. 13 Is shown a modified form of ear clasp 70 of the type shown in the arrangement In Figs. 10 and 11. The clasp 71 is made of a relatively rigid, slightly yieldable strip of metal or similar material and has a front arm 7 1 embracing the helix 72 of the upper auricle junction 45 to the head and an enlarged rear arm portion 78 having a threaded hole In which is threadedly mounted a fastener screw 74 provided with a contact member 71 for clamping the clasp to the ear.

In the modified form of the bone receiver support shown in Fig. 14, two ear clasps 61, similar to the ear clasps of the arrangement shown in Figs. 11 and 12, hold stretched two strip portions 77 of flexible self-aligning fabric material across the rear of the head below the occipital protuberances for coupling to the bones a bone receiver 20 held between the two strip portions It, for instance, by a clamp support 1 1 , of the type shown in connection with Figs. 7 and 8.

The exemplifications of the invention described above will suggest to those skilled in the art many other ways for holding the contact surface of a bone conduction receiver in vibration trans- 03 mltting coupling engagement with the hearing inducing bones of the user, by means of a strip of self-aligning flexible material held stretched along the rear side of the bony skull and head below the greater occipital protuberance for 70 inducing hearing by bone conduction without the discomfort accompanying the use of a head band clamped over the head of the person for supporting a bone conduction receiver. It is accordingly desired that the appended claims be 75

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