US2506981A - Air conduction hearing aid having adjacently mounted microphone and receiver - Google Patents

Description

May 9, 1950 L. G. WEAVER ET AL AIR CONDUCTION HEARING AID HAVING ADJACENTLY MOUNTED MICROPHONE AND RECEIVER Filed Oct. 25, 1946 2 Sheets-Sheet 1 INVENTORS. Jazz/reuse G [11%1/ y Humbert May 9, 1950 G. WEAVER ET AL AIR CONDUCTION HEARING AID HAVING ADJACENTLY MOUNTED MICROPHONE AND RECEIVER Filed Oct. 25, 1946 2 Sheets-Sheet'2 Patented May 9, 1950 UN IT'ED" STATES PATENT OFFICE.

AND RECEIVER LawrenceG Weaven. Evans ton, 111., and- Humbert Milani, Gary, Ind.

Application October 25, 1946, Serial No. 705,724

3 Claims. 1

This invention relates to devices, commonly termed hearing aids, intended for use by persons having defective or impaired hearing, and has to do with devices of this character of the air con.- d-uction type.

In hearing aids of the character referred to, a receiver, in the general nature of a telephone receiver and of which there are various types, is mounted on an insert positioned in the ear and having a projection fitting into the auditory canal. The insert has a passage therein opening through the inner end of theproj ection and comr'nunicating with the output of the receiver, so that an air column is provided which is vibrated in accordance with the diaphragm or analogous element of the receiver. Two types of inserts are commonly used. 'In one-type; the insert is molded from an impression taken from the external ear and the outer or entrance portion of the auditory canal, so as to fit snugly in position within the ear. The other type of insert commonly used is the plug type. It is in the form ofa short tube, which may have a rubber tip provided with one or more annular vanes or flanges, for insertion into the auditory .canal, there being an enlarged head at the outer end of the tube with provision for mounting the receiver thereon.

The receiver is mounted at the .outer end or face of the insert and is readily observable. Many personsrequiringthe use of hearing aids are quite sensitive on the subject and refuse to use such devices, even though needed, since they have a feeling that the receiver and the insert together are quite prominent and attract undesired attention. Since the receiver is mounted on theinsert, at the outer end thereof, itis necessary that itbe made as small as possible, for two reasons. Firstly, by having the-receiver as small as possible, the unsightl rojection, at the side of the head, provided by the-receiver, is kept: as small as possible, rendering it less diiiicultthan would other,- Wise beithe case to persuade persons to wear-such devic s. ...SecQnd1y,thereceiver, ev n tho h as smallas practically possiblapossesses appreciable w i ht an s a r zcaus displacem nt or lo senesS cf theinsertin th car Wh n tha oc feed backtakes place, with resultant squealing which grea ly mu -rsthe effici y of the-d vi e. Further, when the receiver is made quite small,- it has but littleoutput volume with corresponding loss ingefiiciency, :frequently necessitating operation of the transmitter unitat high-power, which may cause objectionable .distortionas 'well as objectionable batteryzdrainage. ,Also, inconstructmg a verysmallreceiver,great careris required in making and assembling the parts, which is time consuming and expensive, and it often is extremely difficult, or practically impossible, to-con-- struct such a receiver with the precision necessary to assure maximum eiiiciency.

The receiver, in the known hearing aid devices above referred to, is connected by two fine Wires,

in the form of a cord, to the terminal contacts- Thatnecessitates at of the transmitter unit.- least eight contacts, two sets of four each, one set at the receiver end of the cord and one set at the transmitter unit end. of the cord. Unless all ofthe contacts of the respective sets are accurately matched looseness and slippage between the contacts is apt to occur, causing objectionable noise and materially impairing the ,efiiciency .of the device. In addition, the wires themselves are a source of trouble and expense. They are necessarily quite fine, for the sake of appearances, and are rather expensive to make. These wires frequently break and have to be replaced, which is an item of appreciable expense to the user, aside from the inconyenience of partial or complete disability of the device ,dueto a broken wire. The wires are, of course, coyerecl with suitable insulation and the rubbing together of the wires causes static which renders it diificult to understand what is .being said. Also, rubbingof the wires, or of U1? 9 3 fi ii fi th 115. l h l ar i larly silk, -ireg ue ntly worn ,by women, causes obi le st ti When a re brea t ends the q ma be h l i loos conta t by e closin n ulat en and a Slight m o of h a d w l ca s bbin t e h o h n of t wi p duc n use i r qus n e n with hearing. If a wire breaks or becomes exposed d a en th r eei t ma som in ntact with the users neck, causing repeated burns, the cumulative effect of which may be a serious burn, which may become infected from the wire, and there are numerous cases where that has oc curred. In that connection, the transmitter unit commonly is grounded to its enclosing metallic casing, and a circuit can be completed from a broken or exposed wire in contact with the users body, particularly if perspiration be present, as in warm weather. There is, also, the risk that the wires may become exposed, due to rubbing offv of the insulation, and come into contact with each other, causing a shortand seriously interfering with the use of the device. Also, in such cases, there is risk that the exposed wires may come in contact with the body and cause burns, even though the transmitter unit is enclosed in a nonconductingcasi-ng formed of. plastic, as is done in some devices. Though there are numerous objections to the use of wires from the transmitter unit to the receiver, no one prior to the instant invention has been able to dispense with such wires and they have been accepted as a neces sary evil.

The instant invention is directed to the provision of a simple and inexpensive hearing aid device in which the receiver may be disposed remote from the ear, concealed by the users clothing or apparel, and may be of comparatively large size, and the necessity of providing wires extending from the transmission unit to a receiver adjacent the ear of the user is eliminated. More specifically, under the present invention the receiver is mounted on and operatively connected to the transmitter unit, and the output of the receiver is connected by an enclosed air column, conveniently by means of a tube of appropriate length, to the passage of the ear insert. By eliminating the Wires, the numerous difficultie incident to the use of such wires are eliminated, as well as the expense of such wires, in the first instance, and frequent renewal thereof. Also, the contacts associated with such wires and the receiver are greatly reduced, or completely eliminated, correspondingly reducing, or eliminating, difficulties due to the presence of such contacts. By disposing the receiver at the transmitter unit, it may be of comparatively large size, which is conducive to increased accuracy and reduced cost of production. Further, a receiver of large size has much greater output volume than the small size receivers presently used and, even when used with a tube of considerable length, gives much better results, both as to volume and clarity than a small sized receiver mounted directl on the ear insert. A further advantage of the instant invention, is that it enables the use of an ear insert which is practically invisible, or substantially so, thus avoiding the objectionable projection beyond the side of the head, encountered in the prior hearing aid devices, currently used, above referred to. Further objects and advantages of the instant invention will appear from the detail description.

In the drawings:

Figure 1 is a front view of the head and shoulder portions of a man wearing hearing aid means embodying the instant invention, with the head shown in about three-quarters front view;

Figure 2 is an inner side or back view of the transmitter unit, with the removable closure member of the casing omitted, and the receiver mounted thereon in accordance with the instant invention, on an enlarged scale relative to Figure 1, the transmitter unit and associated parts being drawn to actual size thereof;

Figure 3 is an inner side or back view of the upper portion of the transmitter unit of Figure 2, on the same scale as the latter figure, with the upper portion the back wall of the casing removed to show the mounting chassis and associated parts;

Figure 4 is a combined side view, on an enlarged scale, of the receiver and associated parts mounted on the chassis, with the latter shown but fragmentarily, and sectional View of the connector member mounted on the receiver and of the ear insert and the tube connecting it to the connector member;

Figure 5 is an inner face view of the receiver of Figure 4;

Figure 6 is a view similar to Figure 3 but show 4 ing a modification with respect to the position and mounting of the receiver;

Figure '7 is a sectional view of the transmitter unit casing, taken substantially on line i'! of Figure 6, the chassi and the parts carried thereby being shown in elevation, this view also showing in elevation the connector member mounted on the receiver and, fragmentarily, the tube extending therefrom;

Figure 8 is an outer face view of the receiver and the connector member enclosed within an air sealing member, mounted on the back plate of the chassis, showing a second modification;

Figure 9 is a sectional view taken substantially on line S9 of Figure 8, the back plate of the chassis and the receiver and the connector memher being shown in elevation;

Figure 10 is an outer face view of the receiver and the connector member mounted on the back plate of the chassis, showing a third modification; and

Figure 11 is a sectional view taken substantially on line H-H of Figure 10, certain parts being shown in elevation.

Preferably, though not necessarily, the ear insert used in the instant invention is similar to the insert disclosed in the copending application of Lawrence G. Weaver, Serial No. 634,597, for Hearing aid, filed December 12, 1945. The insert is molded from an impression taken of the external ear and the outer portion of the auditory canal, fit snugly within the car so as to be effectively retained therein, is preferably formed of a transparent or flesh colored plastic material, and when positioned in the ear is not readily visible. Within the broader aspects of the instant invention, however, any suitable ear insert may be used.

In Figures 1 and 4, there is shown an ear insert I5, preferably similar to the mold insert disclosed in the above identified copending application of Lawrence G. Weaver, as noted. The inse t I5 is provided with an inwardly extending tubular projection l5 having therein a passage ll opening through its inner end. When the insert I5 is properly positioned in the ear, the projection l6 fits snugly into the entrance portion of the auditory canal, into which the inner end of passage IT opens, and the outer end of passage I! opens through the then upper portion of insert IS. The insert I5 is then positioned well Within the external ear, as shown in Figure 1, so as to be hardly visible and, in fact, cannot easily be detected if formed of transparent or flesh colored material.

A flexible tube I8 has one end portion thereof suitably secured in the outer end portion of passage ll of ear insert I5. The other end portion of tube [8 is suitably secured in a short duct or passage IQ of a disc shaped connector member 20. An exteriorly knurled ring 2|, of brass or other suitable material, is embedded in connector member 29 and defines a bore or recess 22 opening through one side face thereof. This bore 22 opens, at its inner end, into a recess or air chamber 23 formed in connector member 20, which air chamber 23 is connected with tube It! through an opening or notch 24 in ring 2 i. A split clamp spring 25 is mounted in ring 2!, adjacent the outer end thereof, in an interior circumferential groove 26 formed therein. The clamp spring 25 provides means for attaching the connector member 20 to a receiver, as will be explained presently.

In Figures 2 and 4 there is shown a receiver 28 suitable for use with the hearing aid of the in- .stant invention. Ibis :rec.eiver :28 :is :or :known type, 3 and is :in. the: form of :a .discxprovided at mic side with a central output ;studi2 9 jhaving are.- stricted neck. The outer face :of receiver :28 lfiat, as isthe inner; face of connector:member 29, so that the latter seats flatwise on 1receiver 28. iltwill be understood that by Pressing connector member 29 toward receiver 28, tthestud .29 BK- .pands the clamp spring :25 .sufiiciently to pass .therethrough, after which this spring contracts about the :restricted ,neck 6,! aofistudg'zfi. thereby detachably securing the connectormemberzdto receiver .28 seating thereon, as above. )AS -:is shown in Fi ure 4, {the deptnof:theidepressionzin member .20, defined by thebore 2210f ring :2! and by theair chamber 23,:is greater thanthe :height of stud 29, providing outward therebeyond :the chamber 23, whichopens freely :into tube l8. There is thus provided enclosed iair column extending from chamber -23 and the output of receiver 28 to passage of projection oritubular element 16 Of the-ear insert l5, passage ,l'irQpen- .ing into the auditory canal of the ear, when insert -'l;-5ris -positionedin the ear in the manner 'described above.

The receiver 23 is provided, at ,its'inner side, with two spaced projections 01211135232 defining between them a dove-tailed groove. This groove receives a cooperating mounting block ;33 suitably secured on aplate 34 of a chassis or mounting :frame 35 of atransmitter unit-3d. The block :33 is provided with two terminal Contact members which cooperate with two similar contact members carried by the receiver 28, for operatively connecting the latter to the transmitter unit 36,

when receiverfifi is properly mounted on block 32, as is known.

The connector member as maybeiormed of any suitable material, but preferably is formed of a known plastic and is either transparent or flesh colored. The tube l8 preferably is formed ofa suitable plastic such as Vinylite, ,though iitzmay be formed of rubber, aeit-her natural or :syn- .thetic, or of any other suitablematerial, and iszpreierably either transparent or flesh-colored.

The transmitting .unit 3 6 is, :asanotedm'fknown type and a brief description thereof will sufiice. It comprises a metallic casing 31 in the upper portion of which is mounted a chassis 35 carrying a microphone, amplifying means including electron tubes, means for adjusting the power output of the amplifier, and associated elements. A B battery 38 and an A battery 39 are appropriately mounted in the lower portion of casing 31, to which they are grounded, these batteries having at one end contact with suitably disposed contact tabs, or fingers, carried by the chassis 35, the latter being secured to the back wall of casing 31 by a screw it which serves as a ground connection. The lower section of the back wall of casing 3'? is in the form of a removable cover, to give ready access to the batteries and permit of removal and replacement of the chassis 35, as may be required. The front wall of casing 36, at the upper portion thereof, is in the form of a grill Work 42 which is disposed in overlying relation to the microphone of the transmitter unit '36. While a transmitter unit, such as that illustrated and above described, by way of example, is preferred, any suitable transmitter unit may be used within the broader aspects of the instant invention.

In the use of the hearing aid device of the instant invention, the insert I5 is properly positioned within the ear and the tube I8 is led upwvard over irthe rear thence downwardiunder wearers clothing :to the connector member :20, which 'mounted upon the :receiver 18 :at the :back cfithe'transmitter unit .135. Theinsert l5, when positioned'iin'thegear, cannot easily be detected and the tube l 8, whichmreferably,is:either transparent :ortintedz flesh color,;d0es not. attract attention, while the receiver ,is -.disposed I at the backer? the transmitter unit :3t,-*which unit :may :be :more or floss completely concealed. The de- 'vice,;as awhole, isimno respect-conspicuous being, :in fact, substantially invisible, and may :be worn "with icomfort. By having the receiver mounted directly; oirthe transmitter-unit thetube .id-may :be of sufiicient length ito permit of disposing the transmitter at. any .desiredposition on the body, while assuring adequate volume and ,high 'clarity :of sound transmission through the tube :l,3,:since the receiver 28 may bemade of any desired size, as-limited only :by thesizerof theunit -36, with the advantages previously mentioned with respect to volume and clarity. By mounting .the receiver 123 -,on :the transmitter unit '35, the necessity for wires extendingfrom theytransmitter to a receiver positioned adjacent the :ear is elimi- .nated, thereby eliminating the numerous difficulties 'encounteredin the use of such wires above pointed out. If desired, a fine 'wire'may be passed-through tube 48 and anchored at its ends to the earv insert li and the connector'member 20, with a view to resisting tension to which tube -18 mightotherwise be-subjected inuse. Under ordinary conditions, the tube l8 possesses adequate mechanical strength and such a reinforcing wire 15111013 required. Also, if-desired,-the tube [8 may be of reduced interior diameter at .the portion thereof adjacent the .ear insert .15, which may be desirable in certain .cases -:as conducive to increasedclarity ;0f hearing-though ordinarily that is-not-required.

.In the modification-shown in Figures 6 and 7, the mounting block 3.3 :of Figures 3 and 4 is omitted and the receiver 2% is mounted-directly on plate :34 of chassis 35, with appropriate oper- .ative connection to the transmitter and amplifier unit, as will bereadily understood. Preferably the depth of casing .s fia, from front to back thereof, is suflicient to accommodate the receiver 28, the back wall of casing 35a having therein an opening 36b of a size to accommodate the connector member 20. By mounting the receiver 28 directly on plate at of chassis 35, with direct connection to the transmitter and amplifier unit, the necessity for providing contacts for operatively connecting the receiver to the transmitter unit is eliminated, thereby avoiding the difficulties incurred with respect to such contacts, above mentioned. By disposing the receiver 28 within casing 36a, it is substantially enclosed and guarded thereby against injury, which is advantageous. A screw iter passes through the back wall of casing 36:; and threads into a member associated with plate 34a, providing a ground connection, as before.

When the receiver is positioned on, or closely adjacent to, the transmitter unit there may be, in certain cases, air leakage resulting in squealing and whistling, interfering, to an objectionable extent, with clarity of hearing. Such a leakage may occur, particularly if the connector member 26 is loosely mounted on the receiver 28. In order to guard against leakage between the re ceiver and the connector member 29, these two members may be enclosed within a container or bag #2, formed of rubber or like material impervious to air, this bag 42 being sealed about the tube 18. If air leakage should occur between the member 20 and receiver 28, the air pulsations or vibrations escaping into the bag 42 will be effectively damped out or killed thereby so that feed back will not occur.

In the modification shown in Figures 10 and 11, the receiver 28a is provided with an exteriorly threaded output stud 29a, on which the connector member a, is screwed, there being a sealing gasket 44 between this member and the receiver 280.. The gasket 44 is formed of suitable rubberlike material, or any suitable material, assuring an airtight seal between the connector member 20a and the receiver 28a. As will be understood, the member 20a is provided with an air chamber 23a beyond the outer end of stud 29a, communicating by way of a short passage or duct 19a with tube [8. By screwing the connector member 20a into tight seating contact with gasket 44, air leakage between the connector member 20a and the receiver 28a is effectively prevented, thus eliminating risk of feed back and resultant squealing or whistling.

What is claimed is:

1. In hearing aid means, a transmitter unit intended to be positioned remote from the earcomprising a protective casing and a chassis therein, a receiver on said chassis operatively connected to said unit, a connector member defining an air chamber mounted on said receiver with the output of the latter opening into said air chamber, an ear insert having an extension disposed to fit into the auditory canal of the ear when said insert is positioned therein and a passage opening through the inner end of said extension, a fiexible tube secured at one end to said connector member opening into said chamber and secured at its other end to said insert opening into said passage, and closure means sealing said receiver and connector member against escape of air therefrom except through said tube.

2. In hearing aid means, a transmitter unit intended to be positioned remote from the ear comprising a protective casing and a chassis therein, a, receiver on said chassis operatively connected to said unit, a connector member defining an air chamber mounted on said receiver with the output of the latter opening into said air chamber, an ear insert having an extension disposed to fit into the auditory canal of the ear when said insert is positioned therein and a passage opening through the inner end of said extension, a flexible tube secured at one end to said connector member opening into said chamber and secured at its other end to said insert opening into said passage, and an airtight member sealed about said receiver and connector member eifective for preventing escape of air therefrom except through said tube.

3. In hearing aid means, a transmitter unit intended to be positioned remote from the ear comprising a protective casing and chassis therein, a receiver on said chassis operatively connected to said unit provided at its outer side with an outwardly extending threaded output stud, a connector member defining an air chamber threaded on said stud with the latter opening into said chamber, said connector member seating on said receiver with an airtight seal therebetween, an ear insert having an extension disposed to fit into the auditory canal of the ear when said insert is positioned therein and a passage opening through the inner end of said extension, and a flexible tube secured at one end to said connector member opening into said chamber and secured. at its other end to said insert opening into said passage.

LAWRENCE G. WEAVER. HUMBERT MILANI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,253,656 Williams Jan. 15, 1918 1,318,874 Hooghiemstra Oct. 14, 1919 1,412,539 Murray Apr. 11, 1922 1,601,063 Frederick Sept. 28, 1926 2,419,471 Thibes Apr. 22, 1947

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