Hydraulically Expandable Earpiece

Abstract

An earpiece is provided for insertion in the ear canal and comprises a tube for conducting sound pressures to the ear canal. The sound pressure tube has a fluid expandable means surrounding the tube and means is provided for forcing fluid into the expandable means to cause it to expand into close fitting contact with the wall of the canal.

Description

This invention relates to devices for transmitting sound pressures into the ear canal from a transducer and more particularly to a means for causing an effective seal between the sound pressure conducting means and the wall of the canal.

One of the problems in transmitting sound pressures from a transducer to an ear is to provide an unobstructed means for conducting the sound to the ear and causing a seal of the earpiece in the ear canal in order that extraneous sounds do not enter the ear and that the conducted sounds do not escape from the ear canal. In particular, a good seal is desired between the means for conducting sound into the ear when the ear is being tested to determine the condition of the ear.

One problem of causing a good fit is complicated by the fact that ear canals are not of uniform size or exactly uniform shape and it is difficult to insert an earpiece and cause an effective seal unless that earpiece is designed for a specific ear. Another problem resided in the fact that the insertion of the earpiece frequently caused the sound outlet to be partially or wholly obstructed.

By the present invention I have provided an earpiece that may be easily inserted in the ear canal and then adjusted to cause it to seal with the wall of the canal and wherein the effect of making the seal causes the outlet to be centered relative to the axis of the ear canal at the point of sound outlet or at least well away from the wall of the canal. It has the advantage that one earpiece can be used in conjunction with an apparatus for testing hearing, with a wide variety of shapes and sizes of ear canals.

Although the invention has a highly practical use in conjunction with apparatus for generating sound pressures for the testing of hearing, and will be described specifically as for use with such apparatus, it will be apparent that it may be incorporated in a great many varieties of earpieces for hearing aids and thus enable the user to more easily insert the earpiece and to adjust the same to his own personal comfort. In the case of use with hearing aids, it is apparent that the acoustical feedback problem can be more easily controlled because of the more effective seal that may be realized, wherein sound does not escape the earpiece, impinge upon the microphone, and cause acoustical feedback.

Still other advantages of the invention and the invention itself will become more apparent from the following description of some embodiments thereof, which are illustrated by the accompanying drawings, and form a part of this specification.

In the drawings:

FIG. 1 is an elevational view, partly in section, of one embodiment of the invention;

FIG. 2 is a view taken at 90.degree. to FIG. 1 and with the earpiece inflated;

FIG. 3 is a fragmentary elevational view of the earpiece according to FIG. 1 illustrating its inflated condition;

FIG. 4 is a view of a modified form of pressure means;

FIG. 5 is a view of the pressure means of FIG. 4 prior to assembly in the casing;

FIG. 6 is a fragmentary elevational view of one end of the casing of FIG. 1, with the cap unthreaded;

FIG. 7 is a sectional view of the invention as applied to an ear mold of a hearing aid;

FIG. 8 is a view similar to FIG. 7 of a modification thereof, and

FIG. 9 is a sectional view of the invention as applied to the sound tube of an over-the-ear type hearing aid.

Briefly, the invention in its broader aspects comprises a sound conducting tube which is surrounded by an inflatable envelope that may be easily inserted in the ear canal. Means is provided for forcing a fluid under pressure into the envelope to cause it to expand and contact the wall of the ear canal. Preferably the envelope is so constructed that the inflation occurs in a toroidal zone near the outlet end of the tube, thus, as a sealing to the wall of the ear canal is effected, the outlet opening of the sound conducting tube is moved to a centralized position transversely of the ear canal.

More specifically, and as best shown in FIGS. 1 through 3, the earpiece includes a base 10 of suitable resilient plastic material in which is disposed a sound-conducting tube 12. The tube projects through the bottom of the base 10, which may be cylindrical, sufficiently that another tube which conducts sound pressures may be coupled thereto. The tube extends through and above the base and curved outwardly at 12a .

An inflatable envelope is molded integral with the base on the top end and comprised and inner wall 14 and an outer wall 14a. This envelope surrounds the curved portion of the sound tube 12 and terminates close to the end of the tube. Preferably the end of the envelope at 14b is slightly thicker than the remainder. A duct 10b extends through base 10, the one end opening into the space between the walls of the envelope and the other end being formed with a tubular extension 10c below the base.

Although the envelope may be made with a substantially uniform wall thickness, it is preferred that a zone, as indicated by the bracket 14c surrounding the tube 12a be slightly thinner whereby when fluid is forced between the walls of the envelope, that zone expands to a greater degree than the remainder to a generally toroidal form as shown in FIG. 3.

Various means may be provided for forcing a fluid, which may be, and preferably is, a liquid, into the space between the walls of the envelope. One such means includes a bulb 20 which has a thin distortable wall and is connected to a valve housing 22, which has a chamber 22a with a frustoconical valve seat 22b therein, upon which a ball valve 24 may seat. The upper end of the chamber is provided with a frustoconical wall 22c whereby the ball is confined in the chamber but can move a short distance off of the valve seat. The valve chamber communicates by a duct 26 in an upper part 26to a chamber 26b which in turn connects with the tube 10c. All of the parts have sufficiently greater wall thickness than that of the envelope and the wall of the chamber 26b, so that pressure within the system results in expansion of the envelope walls 14, 14a and 14c.

The chamber 26b, being outside the ear canal, can also expand after the expansion of the envelope, thus preventing the application of undue pressure to the wall of the ear canal and also acts as a visible indicator for indicating the fact that the envelope has been expanded and for storing the excess fluid.

Preferably the parts are all molded from a flexible plastic such as an elastomer. One method contemplates molding the base 10 with its envelope 14--14a and the tube 10c as one part, the expansion chamber 26b and valve chamber 22 as another part and the bulb 20 as a third part after which the ball valve may be inserted. The parts may then be assembled with each other and secured together by heat sealing or cementing. The tube 12--12a may now be inserted in position, with the one end projecting below the base and the other slightly beyond the end of the envelope 14--14a. The entire space within the elements is then filled with a suitable liquid such as glycerine, alcohol or other nonfreezing liquid, and all the bubbles removed. The filling and removing of air bubbles may be done with a hypodermic needle, after which the puncture is sealed.

The device is now ready for use. A sound tube from a transducer is secured on the knurled lower end of the sound tube 12. The device being deflated, the sound tube with its encircling envelope is easily inserted into the ear canal. The bulb 20 is then pressed between the fingers. This causes the liquid to force the ball valve 24 off the seat 22b and the liquid to pass from the bulb through the valve chamber into the duct 26 and the safety or indicator chamber 26b, through the duct 10c and 10b and into the space between the walls of the envelope. As the pressure is increased the envelope expands and particularly the zone 14c around the tube 12a, which zone eventually engages with the wall of the ear canal.

As stated, the extremity 14b of the envelope is preferably somewhat stiffer than the remainder to prevent the envelope from going beyond the outlet end of the tube 12a. The zone 14c expands to a generally toroidal shape as best shown in FIGS. 2 and 3. The expansion may be effected by alternate compressions of the bulb 20 which gradually collapses. Each time the bulb is released, the valve 24 seats on the seat 22b regardless of the attitude of the device. Eventually a slight expansion of the chamber 26b will be visible, which will occur when the envelope has sufficient contact with the wall of the ear canal to effect a seal. The chamber thus not only serves as a safety and comfort control factor but also as an indicator that a seal has been effected.

It is apparent that the insertion of the device in the ear is without discomfort. The size of the base 10 limits the distance the tube 12 can be inserted in the ear and eliminates the pushing and twisting that has heretofore been necessary to provide an effective seal. Further, there is no need to rely on the subjective determination by the patient that the device is in far enough or is sealed. As the envelope expands it will eventually contact the wall of the ear on one side or the other. Then the other parts expand until the entire circumference is in contact with the canal wall. This has the effect of centralizing the sound outlet in the ear canal which provides best transmission of sound to the eardrum. The sealing will be apparent by observing the expansion of the indicator chamber 26b.

The testing of the hearing may now proceed according to plan. The valve 24 holds the liquid pressure indefinitely. When it is desired to take the device out of the ear it may be simply pulled out without any discomfort to the wearer. Pressure in the envelope may be released before or after the device is pulled out of the ear canal by simply pressing the wall the chamber 22 to distort that chamber and the valve seat and render the valve and seat ineffective; at this time the liquid bypasses the valve and is automatically sucked back into the bulb. This is effected because of the fact that the wall of the bulb is thicker than the wall of the envelope and the safety or indicator chamber and when the valve is released the bulb wall expands and sucks the fluid back into the bulb.

It is highly desirable that the liquid in the device be without gas bubbles. Originally it can be filled and the bubbles removed as stated. In some instances the liquid may vaporize, particularly of there is insufficient liquid to cause a pressure sufficient to prevent vaporization of the liquid More particularly after the bulb 20 has been compressed the tendency of the wall to return to its original form causes a pressure below atmosphere in the bulb with the tendency to cause the air to penetrate into the bulb and cause air bubbles. In FIGS. 4 to 6 inclusive, I have shown a modified form of pressure means where a predetermined amount of pressure may be maintained to prevent such vaporization and the ingress of air and wherein piston means is used to apply and hold the pressure. The ball valve and its seat is eliminated.

Briefly, the modified pressure system comprises an elongated bulb, one end of which has a solid piston member integral therewith and the end wall of the bulb with the piston member is folded upward withing itself and the bulb encased in a metal casing having a threaded cap on the end, which cap engages with the piston to force it upward, thus always maintaining a predetermined pressure within the system.

Referring to FIGS. 4 and 5, the base 10 with its ducts and sound tube is the same as described as is the indicator or safety chamber 26b. The pressure bulb in this instance includes a thick top wall 30 (FIG. 5) from which the thin tubular sidewall 30a depends, the sidewall in this showing being collapsed inasmuch as it is not filled to the extent the bulb 20 was filled, to enable it to eventually be folded back within itself. At the lower end the sidewall merges with a piston which comprises a solid upper portion 30b and a lower portion 30c which has a cylindrical bore 30d which receives the end of a metallic operating rod 32.

As can be seen from FIG. 4, the solid piston portion 30b may be pushed upward to cause the lower part of the wall 30a to be folded upward inside of the other portion for approximately one-third of the length of the bulb, thus causing the liquid displaced by the folding to be forced into the upper part of the bulb which expands from the contracted shape shown in FIG. 5 to cylindrical shape shown in FIG. 4 into contact with an outer metallic casing. The metallic casing is provided to enclose the bulb and its piston and includes a cylindrical sidewall 36 having an inturned upper end 36b which defines a flange having an opening through which the indicator chamber member 26a projects with the shoulder defined by the thickened part 30 bearing against the inside surface of the flange 36b. The body of the casing extends downward and has an exteriorly threaded end 36c which terminates slightly above the end of the piston stem 30d. An internally threaded cap 38 is threaded on the end of the body and is provided with a central opening through which the operating pin 32 may extend with a sliding fit. When the cap is threaded onto the casing, the inner end wall of the cap engages with the stem 30d and pushes it along with its piston upward, causing the liquid to be under pressure. The pressure is such that there is no tendency for the fluid to vaporize or for air to be sucked through the wall and no bubbles, which are highly deleterious to the action of the device, will form.

When it is desired to expand the envelope 14, pushing the piston operator upward into the casing causes the fluid in the bulb to be pushed upward the same as described for the other embodiment.

Many different means may be provided for operating the piston rod, the one shown being by way of illustration and not of limitation, and comprises a groove 32a formed in the wall of the pin or rod 32, which enables the wall of the groove to be engaged with the wall of the cap 38 surrounding the opening when the rod is moved to one side. A series of these grooves may be provided to enable different pressures to be obtained.

The above-described devices are particularly useful in cases where clinical testing of hearing is being made because it allows the technician to quickly and easily insert and remove the tube coupling the transducer to the ear canal and assures that a tight centered fit is obtained therewith. As previously mentioned, the invention is also useful in conjunction with the various types of hearing aids where sound is conducted to the ear canal. These may include the ear-mold type as shown in FIGS. 7 and 8 or the tube from an over-the-ear or eyeglass type as shown in FIG. 9.

FIG. 7 illustrates a type where a transducer 40 is provided with a curved tube 40a and the molded portion 42 is fitted to the ear in the usual manner. In this instance the mold is provided with a cavity in which a flexible bulb 44 is disposed. The bulb projects beyond the base of the mold and is compressed when the transducer is assembled with the mold by virtue of the fact that the transducer has the usual coupling 40b, the enlarged outer end of which snaps into the cavity ring or groove 42a when the two are forced together.

bulb connects to the interior of an envelope 46 surrounding the mold and provided with a toroidal expansion portion 46a near the end of the tube 40a. In practice one way is to insert the ear mold into the ear with the transducer pulled away from interlocking engagement with the mold and then after the ear mold is in place, press the transducer into locking engagement with the ear mold which causes the flat wall of the transducer to compress the bulb and force the fluid into the expandable zone.

Another embodiment of the ear-mold type is illustrated in FIG. 9. In this instance the ear mold 50 is formed in the usual manner and provided with a cavity 52 of generally cylindrical form which necks down to an opening 54 at the end which extends into the ear. The transducer has a sound tube 56a. The expandable means includes a base 58 which snaps over the coupling 56b. Upwardly of the base is a bellows 56c which surrounds the tube and connects to the expandable portion 56d of the envelope. Normally the bellows is sufficiently stiff that it moves to its contracted position. When it is desired to insert the transducer in the ear the transducer is moved outwardly of the ear-mold, causing the bellows to expand and the fluid to run into the bellows allowing the expandable seal portion 56d to contract. Being held in this position the entire assembly is inserted into the ear in the usual manner and the transducer then released. This causes the bellows to contract and force the fluid into the part 56d, sealing the tube 56a (and centering it) with the ear canal.

Although over-the-ear and eyeglass type aids can be designed with arrangements for expanding the end coupling, similar to that shown in FIGS. 1 and 4, a very simplified type of coupling is illustrated in FIG. 8. In this instance the tube 60 connects to the sound tube 62 and is provided near its end with a bushing type of envelope that surrounds the tube. This envelope may include an upper end portion 64 and a lower end part 64a with the lower part 64a considerably heavier and stiffer than the part 64. Thus, when it is inserted in the ear canal the part 64 may compress and the fluid flow into and expand the part 64a, always leaving a tight fit of the part 64 with the ear canal.

It will be appreciated that the above are but a few of the many ways in which the invention may be applied to hearing aids per se and they are shown by way of illustrating the invention and are not intended to limit the invention other than is expressed in the appended claims.

Claims

I claim:

1. An apparatus for conducting sound pressure into an ear canal and having an outlet end disposed in the canal and expandable means surrounding the conduit, said means arranged to be expanded into contact with the wall of the canal after insertion of the conduit, and said expandable means being arranged to expand radially outward and hold the sound pressure conduit away from the wall of the canal in longitudinally restricted zone near the outlet end of the sound conducting conduit, a base supporting said sound pressure conduit and being connected to fluid pressure means by a connecting means, said fluid pressure means including a fluid pressure pressure reservoir, a wall of which is movable to force fluid out of the reservoir said connecting means including valve means and also including an expandable chamber which expands when the expandable means expands.

2. An apparatus as described in claim 1 wherein said valve means includes cylindrical chamber made of distortable material having a seat on one end and a valve is disposed on the seat and said chamber may be distorted upon pressure from outside of the chamber to distort the valve seat and release the fluid.

3. An apparatus for conducting sound pressure into an ear canal including a sound pressure conduit for insertion into the canal and having an outlet end disposed in the canal and expandable means surrounding the conduit, said means arranged to be expanded into contact with the wall of the canal after insertion of the conduit, and said expandable means being arranged to expand radially outward and hold the sound pressure conduit away from the wall of the canal in a longitudinally restricted zone near the outlet end of the sound conducting conduit, said fluid pressure means comprising an envelope filled with fluid and casing means for housing said envelope and piston means in the casing operable from the outside of the casing to cause the fluid in the envelope to be displaced, said envelope being elongated with a portion of the sidewall and one end wall folded back into the other part and the end wall having a piston which includes a cylindrical portion integral with the end wall.

4. A device as described in claim 3 wherein said piston has an extension that extends toward the end of the casing and threaded cap is provided on the end of the casing arranged to contact the end of said extension.

5. A device as described in claim 4 wherein said cap is provided with an opening and said extension is provided with a base and an operator member is seated in the base and extends through the cap opening.

6. A device as described in claim 5 wherein means is provided for engagement with the operator member to hold the operator in a predetermined position.