US2874231A

US2874231A - Ear mounted hearing aid device

Info

Publication number: US2874231A
Application number: US550642A
Authority: US
Inventors: Frank B Wallace
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-12-02
Filing date: 1955-12-02
Publication date: 1959-02-17
Anticipated expiration: 1976-02-17

Description

Feb. 17, 1959 A C 2,874,231

EAR MOUNTED HEARING AID DEVICE I Filed DG C. 2, 1955 I 2 Sheets-Sheet 1- I N VEN TOR.

Feb. 17, 1959 WALLACE 2,874,231

EAR MOUNTED HEARING AID DEVICE Filed Dec. 2, 1955 2 Sheets-Sheet 2 ARBIT RARY' FIG. 7

a 8 O 9 m IN VEN TOR.

Mia/4m BWMKZMZ/ United States Patent O,"

2,874,231 EAR MOUNTED HEARIN G AID DEVICE Frank B. Wallace, Phoenix, Application December 2, 1955, Serial No. 550,642

4 Claims. (Cl. 179-407) This invention concerns improved hearing aids and a method for improving the hearing of persons who do not have normal hearing.

Heretofore hearing aids consisting of a microphone sound pickup, an electrically operated amplifier, and an air transmitter, a bone transmitter, or skin transmitter have been made and used in various forms all of which, however, have the common fault of over amplifying certain unwanted sounds and of not providing any mechanism for determining the direction from which the sounds originate. It is an object of the present invention to provide a hearing aid which will amplify sounds within ranges so that a person having impaired hearing will be able to perceive and receive speech and music in a manner approximating that of normal hearing.

Another object of the invention is to provide a method, mechanism and combination of parts which will aid a person having impaired hearing to hearsounds, corrected to normal proportions both as to quality and as to the direction from which the sounds emanate. This latter condition is sometimes called the stereophonic or directional eifect of sound, and it is an object of the invention to provide apparatus andan arrangement'thereof, as well as a method'of use, which will enable a person with impaired hearing to regain the directional and tonal response'of normal hearing. Still another object is tofprovide mechanism,.parts and combination of parts that will amplify sounds within those ranges which, are impaired so that a balanced sound effect is secured that will tend to restore balanced normal hearing to theuser. i I Still anotherobject is to provide apparatus for the purposes s ave stated" that will break uploud noises so that they do-not blast or cause unpleasant effects which may cause damage to the ears of the user.

.dnotherl object is to provide apparatus, as above mentioned, in whichhsoilinds within certain predetermined ranges are implied transmitted to either the a d um or ct erhear ns vme a h e he sounds are-transmitted directly to the organs of hear-. ing by a separate channel.

Another object is to provide a. device wherein the microphone sound pickup mechanisms are adapted to .be worn in either or both ears of the user whereby the lateral surfaces of the car are utilized to break up, modify and/or direct soundsimpinging thereon to a microphone pick up.

Another object is to provide instruments as above described wherein the microphone is small'and adapted to amplify sounds of selected highfrequencies in order to produce amplified sounds to normalize "hearing.

St aa th r o ec s o Pr a s. n Pa s in u i microp o es w h e a ra at that there is as e i e fee back at fr m reproduce: or other parts of the apparatus which is p 2,874,231 Patented Feb. 17, 19 59 2 likely to cause squealing or screeching or other unwanted extraneous sounds.

Other objects will appear hereinafter.

I attain the foregoing objects by means of the devices, apparatus, parts and combination of parts shown in the accompanying drawings, in which- Figure 1 is a side elevation of one form of my device, shown as applied to the right ear of a person needing hearing aid;

Figure -2 is a section taken substantially on line 2-4 of Figure 1 showing the position of the apparatus as viewed from the front;

Figure 3 is a diagrammatic representation of the electrical connections of the several parts of the apparatus;

Figure 4 is a section of apparatus incorporating my invention but made according to a slightly modified variation as to the position of the audio reproducer;

Figure 5 is a side elevation of another modified form of hearing aid embodying my improvements;

Figure 6 is a transverse section of the aid shown in Figure 6, taken substantially on line 6-6, Figure 5; and

Figure 7 is a chart showing various curves illustrating the relation of usual hearing loss to pitch and the relation of microphone response to pitch as concerned in the apparatus concerned in my invention.

Similar numerals refer to similar parts in the several views. 1 r

In keeping with the objects above stated, I have pro: vided a microphone which can be attached to and worn adjacent each ear of the user if desired. While in the Figures 1, 2, 4, 5 and 6 of the drawings only the right ear is shown, it is to be understood that a left hand counterpart of the apparatus shown will be made for use on the opposite car, when desired.

This right and left structure and arrangement make it possible to obtain a stereophonic effect, and enables the user to have and maintain directional perception for his hearing. v

In keeping with the objects above stated wherein it is desired to restore natural hearing insofar as possible, I provide a microphone which has a natural resonance to vibrations above those heretofore used. This type of microphone is very small, and can be worn on or adjacent the ear of the user so that it will pick up sound vibrations reflected from the fossa of the antihelix of the car. It makes use of the sound handling 'qualities of the outer ear and, therefore, simulates sounds received by the natural action of the ear of a person using the devices.

in addition to sounds picked up by the microphone or microphones for amplification, I provide a channelway so that low-pitched sounds will reach the ear drum of the user without amplification and will supplement and mingle with those supplied by a reproducer or re:

- I a d a r ce producers which are received by a microphone or microphones and amplified by electrical means so that vibrations in the range of the higher audio frequencies are given proportionately greater amplification.

Referring to the drawings, and particularly to Figures 1 and 2 it is to beunderstood that numeral 2 indicates the ear, in this case the right ear, of the user. Numeral 3 indicates the helix of the ear; numeral 4 the tragus, and numeral 5 the anti-tragus; while numeral 6 indicates the recess of the lower part of the outer car which leads to the aural canal 7.

A molded microphone support or car piece it) is fitted into the recess 6, and is held by contact with the tragus Optionally, a U-shaped rubber covered clamp 11, provided with an adjusting clamp screw 9,

as shown in Figure 4 may be used. The ear piece is made of a semi-hard plasticisable material, and attached to this there is a soft rub'ber cap or microphone case 12. This may be attached either by casting keys 12a on the body of case 12 into the ear piece 10, or by welding or by cementing the contacting parts together. The case 12 surrounds, shields and pads the microphone 14 excepting its diaphragm 15. This diaphragm faces inward toward the fossa of the anti helix 8 of the ear 2, and/or, partly toward an angular outer surface of the ear piece 10. Case 12 is positioned and set at an angle so thatthe diaphragm 15 is not adjacent to any sound reflective surface that would cause echoing and re-echoing to the extent that undesired sounds are not over amplified and reproduced. Thus, the outer surface 17 of the ear piece and microphone support 10 is at a non-reflective angle to the face of the microphone diaphragm 15. This same non-reflective relation is also maintained between all parts of the ear surface and the microphone diaphragm 15. i

The outer portion of the human ear is shaped by nature to normally adequately catch all sounds likely to be encountered in natural life. These sounds include audio vibrations having frequencies varying from approximately 10,000 vibrations per second to approximately 32 vibrations per second. The fossa of the antihelix of the ear refiect and direct these sounds through the aural canal of each ear to the organs of audio perception or hearing. The ridges and convolutions of the fossa of the antihelix of the human ear break up, distribute, and direct these sounds so that no one sound, or group of vibrations, is over emphasized and no group or sound is unnaturally suppressed. Echoing and unbalance of harsh sounds is thus prevented. By directing or facing diaphragm 15 of the microphone 14, toward the fossa of the antihelix of the ear 2, as above mentioned, the microphone becomes responsive to sounds received, caught and reflected from these surfaces. Harsh sounds likely to be over emphasized in an amplifier and reproducer are suppressed, and weak sounds are not drowned out by heavy sound vibrations so that all desired sounds are received by the microphone and their natural timber is preserved.

I If the microphone diaphragm is directed outward harsh sounds often over balance desired sounds and there is much distortion.

The ear piece and microphone support 10, while it extends across the recess 6 of the ear fore and aft, does not crowd tighly against the opening to the aural canal 7, but is shaped so as to provide an open channel or passageway 18 between the upper surface of the ear canal and the edge of its upper part. Due to this construction, sounds may enter the aural canal 7 in the usual and normal manner and are transmitted to the organs of hearing in the inner car through opening 18a, so that they will function so far as they are capable.

Electrical impulses from the microphone 14 are led through a double conductor electrical cable 21 to a conventional amplifier 22, and thence through a double conductor cable 23 to a sound reproducer 24, as'shown diagrammatically in Figure 3. This reproducer 24 may be of any type desired, and the type used depends upon the impaired condition of the organs of hearing of the user.

As an example, I have shown in Figure 1 one type of reproducer which may be called a Skin Transmitter and which includes conventional means of converting electrical impulses into mechanical vibrations of a vibrating armature which is pressed against the skin of the users head in an area indicated generally by numeral 25, and which is closely adjacent the ear 2. As shown, the reproducer is held by a head strap 27 which curves around the users head, and which mayalso carry its left-hand counterpartfor use on the left ear if a microphone is used in the left car. This skin transmitter and reproducer is shown as one means, only, of conducting amplified sound to the organs of hearing. A conventional type of bone conducting reproducer (not shown) may also be used. Also, an air conduction reproducer .31 may be used, such as is illustrated in Figure 4.

In Figure 4 a reproducer holder 30, made of plasticisable material, is fitted into the upper part of the outer ear 2 and is secured by a plug 32 which fits into the aural canal 7 and by a horn 33 which fits into the folds of the helix 3 of the outer ear 2. It is important that the solid body of the holder 30 does not physically contact the solid body of the ear piece 10 which holds the microphone 4. A separation between these parts is necessary so that there will be no audio feed-back of the amplified sound from the reproducer 31 to the microphone 14. As shown, the air reproducer 31 includes a conventional diaphragm which transmits sound through channel 34 extending through the body 30 and plug 32 and opening into the aural canal 7. Plug 32 also contains a separate channel 36 which opens into the space 18 between body 10 and the body 30, and leads to the outer air, so that low-pitched sounds may enter from the outer air into the canal 7 and energize the organs of hearing of the inner ear.

In this form of the device a microphone 14 is mounted on car piece 10 in the same manner as that shown in Figures 1 and 2, and is likewise electrically connected through an amplifier to the reproducer in a similar manner. Transmission of amplified sound is made by air conduction through the channel 34.

In Figures 5 and 6 a modified form of my hearing aid is shown. This form has the ear piece 50 positioned within the upper part of the outer ear portion 49. It is molded to the contours of the soft folds of the upper outer ear and retained by a horn 51 which projects into the fold of the helix. The microphone 52 is secured in soft rubber case 53 which is, in turn, fitted into a recess in the body of the ear piece 50. The recess is shaped so that the sound-receiving diaphragm 54 of the microphone 52 is directed upward and inward toward the fossa of the antihelix 55 of the ear 2.

In the lower and outer part of the ear 49 there is a molded ear piece and plug 57 which is shaped to the contours of the lower part of the ear, and is held by retention of the tragus 58, and the anti-tragus 59, as well as by the plug 60 which fits into the aural canal (auditory meatus) 7.

In the lower part of the lower ear piece 57 there is a channel 62 which extends from the outer face 63 of plug 57 to the inner end of plug 60 where it opens into canal 7. A flexible tube 64 of plasticisable material is fitted into the outer end of this channel and connected to a reproducer 65.

In the upper part of ear piece 57 and plug 60 there is another channel 67 which leads to the outer air through and outside of the sponge rubber pad 68.

In this form the two

ear pieces

50 and 57 are separated by sponge rubber 68 or by a corresponding open space. This minimizes the likelihood of audio feed-back from the piece 57 to the microphone 52. In this structure the channel 67 is extended outward until it reaches the open air. It is to be understood that channel 67 affords a means for the conduction of sounds from the air directly to the organs of hearing of the inner car, while channel 62 furnishes auditory vibrations to these organs through tube 64 and from reproducer 65. The reproducer is, in guzrn, energized by amplified vibrations from microphone With reference to Figure 7, curve L is a typical hearing loss curve showing the loss increasing in the high pitches. The loss in decibels is shown at the left. The curves M and M show microphone responses in relation to pitch. The same pitch scale is used, as shown at the bottom of the sheet, for all curves.

The ordinates of curves M and M' represent the intensity of response to an arbitrary scale. The high point of the curve is at the resonant pitch of the microphone diaphragm. Curve M represents the response of a microphone as ordinarily used in a hearing aid which must cover the field. That is it. must amplify at all audible pitches. Curve M represents the intensity of response of the microphone in my improved hearing aid in which the amplification of the low pitches is unnecessary as the low pitches are received directly by the ear in the usual way, through the ear drum and through bony surfaces such as temples, cheek bones, etc., with reference to curve M, since the microphone used is smaller in size, and has a higher resonant pitch, in the order of 5000 vibrations per second, and would fail in the low pitches if these pitches were needed.

Less amplification is needed of the sounds in the microphone producing curve M in my improved hearing aid because the amplification is confined to the pitches needed for understanding, and for the following reasons:

(a) Usable sounds are not drowned out by overamplification of middle range sounds;

(b) Most important sounds for understanding are not drowned out;

(0) Undesirable sounds like scraping of a chair, street noises, air conditioning fans and innumerable others not over-amplified.

If the hearing of one ear is impaired, to a greater extent than the other the apparatus will be used on the poorer ear only. Further, if both ears are treated and there is a difference in the degree of impairment of hearing of the ears the apparatus can be adjusted accordingly since there are separate amplifiers and reproducers for each ear. It is to be understood, further, that the microphone, being adjacent the irregular lateral surfaces of the ear, picks up sounds in a natural way and avoids the over-emphasis of low sounds which give the unpleasant and damaging boiler factory eflect found in many conventional hearing aids when amplification is increased. When the apparatus is made and positioned as above described, audio feed-back is eliminated. This is done by adequately cushioning the microphone and by placing it where there are no oppositely positioned reflective surfaces; also if the microphone and reproducer are closely positioned their vibrating elements are positioned so that they do not vibrate in parallel planes. In all cases sound transmitted to the ear canal or to tissues and structure adjacent the ear is kept away from the microphone diaphragm as far as possible. Lastly, the aural canal is left open to the outer air so that low-pitched sounds may be heard directly.

The over-all effect of my apparatus and its arrangement is therefore to improve the hearing of the user, both as to quality of the sound perceived and as to direction of its source.

While the apparatus above described is particularly adapted to the method disclosed, it is to be understood that the method is adapted to any apparatus that will function to achieve the steps necessary. The method consists in receiving sounds reflected from the outer surface of one ear of the user by a microphone, or its equivalent, amplifying these sounds and transmitting them, or their corresponding vibrations, to the organs of hearing of the same ear.

The method contemplates that sounds are selectively picked up and amplified according to pitch. Sounds which are least perceived by the user are given the greatest amplification. Low pitched sounds are applied to the organs of hearing in the natural manner wherever possible.

Perception of sound by each ear is treated and restored separately so that a balanced natural over-all eflect is attained as a final result.

I claim:

1. A hearing aid microphone and a support combined therewith for supporting the microphone adjacent to the fossa of the antihelix of the human outer ear comprising an ear piece shaped to fit the outer end portion of the aural canal of the human car, an apertured soft rubber microphone case having the apertured side thereof directed toward the fossa of the antiheiix of the outer ear, said case having one end thereof secured to said ear piece with said case extending outwardly therefrom, a microphone supported in and encompassed by said microphone case on all sides except the apertured side of said case, and a microphone diaphragm in said microphone positioned in aligned relation to the open side of said case and directed toward the fossa of the antihelix of said outer ear whereby sound waves received and concentrated by the fossa of the antihelix of the outer ear are effective to vibrate the microphone diaphragm.

2. -A device as claimed in claim 1 wherein said ear piece is provided with a passage open to the atmosphere at its outer end and communicating with the aural canal at its inner end to permit passage of low pitched sounds audible without amplification.

3. A device as claimed in claim 1 wherein said microphone case shields said microphone from sound waves other than the sound waves reflected from the fossa of the antihelix of the outer ear.

4. A device as claimed in claim 2 wherein an air reproducer is supported on said ear piece and a second passageway extends through said ear piece communicating said air reproducer with the aural canal inwardly of said ear piece.

References Cited in the file of this patent UNITED STATES PATENTS 2,506,981 Weaver et a1 May 9, 1950 2,528,811 Balbi Nov. 7, 1950 2,718,563 Nicholidis Sept. 20, 1955 2,765,373 Smith Oct. 2, 1956 2,787,670 Rowland Apr. 2, 1957