US 2430229 A
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Nov. 4, 1947. E. KELSEY HEARING AID EARPIECE Filed Oct. 23, 1945 3 Sheets-Sheet l INVENTOR. ELIZABETH L. KELSEYI W 5.
Fig 5 HER A T'T-ORIVEY Nov. 4, 1947. E. L. KELSEY 2,430,229
HEARING AID EARP-IEGE Filed Oct. 23, 1943 3 Sheets-Sheet 2 HIGH 2 GAIN AMPLIFIER INVENTOR ELIZABETH L.KELSEY HER A T TORNEY Nov. 4, 1947. E. KELSEY HEARING AID EARPIECE Filed Oct. 23, 1945 3 Sheets-Sheet 5 III I INVENTOR ELIZABETH L. KELSEY Ill W6 HER ATTORNEY Patented Nov. 4, 1947 UNITED STATES PATENT OFFICE HEARING AID EARPIECE Elizabeth L. Kelsey, Chicago, Ill., assignor to Zenith Radio Corporation, a corporation of Illinois 3 Claims.
This invention relates to hearing aid apparatus of the air conduction type.
It is desirable to make hearing aid apparatus of small size suitable for inconspicuous wear by th user, and especially those components including the earphone and earpiece mounted near or in the ear of the user. The earpiece must give minimum discomfort to the user and yet be of such design and shape as to fit the individual user whereby it is firmly supported in place and whereby acoustical feedback and masking eifects from outside noises picked up by the ear simultaneously with sound arriving through the earpiece are eliminated.
In hearing aid circuits including a high gain amplifying device connected between the microphone and speaker wherein the microphone and speaker, or arpiece, are in relatively close proximity to one another, sound emitted from the speaker, or earpiece, may impinge on the microphone o elements of the high gain amplifying device in sufficient intensity to cause an annoying singing or buzzing noise in the earpiece. It is desirable, of course, to prevent such singing or buzzing noise from being superimposed upon the desired sound impinging on the microphone. It is therefore an object of this invention to provide an improved sound sealing means to fit between the body of an earpiece and the contacting portions of the ear of a user such that a high gain amplifying device may be used to advantage without disturbing effects.
In addition to the above described qualities, the earpiece preferably is of such material and size and shape as to conform to the size and shape of individual ears differing Within normal limits.
Therefore, another object of this invention is to provide an improved construction of an earpiece adapted to the differing sizes and shapes of individual ears, and further to provide certain details and features of construction which tend to increase the efliciency and desirability of such a device when used with a sound producing element for properly transferring sound to the ear without feedback or losses in frequency response due to shape, size or acoustical coupling of the earpiece or connection thereto.
Another object of this invention is to provide improved apparatus for the carrying of sound from a source thereof to the ear, such apparatus being particularly adaptable for use with hearing aids, radio sets, transceivers, dictaphones, and electro-stethoscopes, the size and shape of such apparatus permitting use under headgear, such port th earphone connected to such earpiece solely by the earpiece supported within that auditory canal.
Still another object of this invention is to provide an improved form of soft rubber earpiece of small size suitable for inconspicuous wear by the user.
Still another object of this invention is to provide an improved earpiece for use with hearing aid apparatus having a high gain amplifier connected between the microphone and sound reproducing device or speaker.
Yet another object of this invention is to provide a set of such earpieces for use in any individual ear differing in size and shape within normal limits.
The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which:
Figures 1 and 2 show, respectively, an assembled and an exploded View of parts of an im-v proved earphone and associated apparatus embodying the present invention;
Figs. 3 and 4 show in detail the construction of apparatus shown in Figs. 1 and 2;
Fig. 5 shows groups of earpiece apparatus embodying the present invention;
Figs. 6 and '7 show, respectively, end views of apparatus taken substantially on line 6-6 and line l'! of Fig. 5;
Figs. 8-10 show modified apparatus for realizing certain features of the present invention, and
Fig. 11 shows hearing aid apparatus embodying the present invention in a human ear.
Referring to the drawings, wherein the same numerals are applied throughout to similar parts, Figs. 1 and 2 show respectively an assembled view and an exploded view of parts of hearing aid apparatus arranged to be supported substantially entirely by engagement of an earpiece I0 Within the external auditory canal, or meatus, of individual ears differing in size and shape. These parts comprise an earpiece or plug I8 formed of material such as soft rubber havig a sound transmitting channel I I extending therethrough arranged in communication with sound transmitting channel I2 of earpiece holder or angular earphone stud I3, the earpiece holder or stud I3 being releasably and resiliently held within earplug III and having its sound transmitting channel 23 in communication with the sound emitting opening I 4 of speaker unit l5 by means of a resilient split ring I! loosely held in an annular groove I8 within stud I3 and arranged to engage the inner edge of speaker flange I9. The split ring I! may take other forms as shown in Fig. 8 for the same purpose.
The sound channels I I, I2 and I4 are preferably round in cross section and are made as large as possible consistent with suitable strength in the wall thickness of the studs, earpieces and earphone. It has been found that when such sound channels have a diameter which is too small, unsuitable transfer of sound energy takes place. In the hearing aid apparatus shown herein suitable transfer of sound energy takes place when the diameter of the openings I I, I2 and I4 are in the order of one-tenth of an inch.
The earpiece I 0 is releasably and resiliently held on its holder or stud I3 by cooperation of the flange on stud I3 within the enlarged annular inner groove 2I of earpiece I8, the earpiece or plug Ill being attached to and detached from its holder I3 by distorting the shape of the rubber earpiece I0 and moving it off the holder I3. Such easy removal allows a resilient earpiece of any suitable size to be conveniently attached to holder I3 or removed therefrom so that a user may readily select and try different sizes and shapes of earpieces forming a set.
The earpiece I0, and other similar ones shown herein, are made of soft resilient material, not only for allowing earpieces of different sizes comprising a set to be readily attached to and detached from the holder I3 but also to provide soft expansible surfaces arranged to avoid injury or discomfort to the ear when inserted therein and to cause a suitable engagement or sound seal be tween the body of the earpiece Iil and the walls of the external auditory canal.
Specifically, earpiece I0 comprises a resilient body portion 23 having integrally formed spaced flanges 24 and 25 arranged to engage the walls of any individual auditory canal differin in size and shape, the rearward portion of the earpiece I 0 having a flared portion 26 arranged to seal the mouth of such canal and to limit the depth to which the earpiece I0 is inserted in the auditory canal." The forward soft resilient flange 25, not braced by holder I3, when it is in operative position, provides a soft cushion so as to avoid injury or discomfort to the car when the earpiece is inserted into the auditory canal. The particular arrangement and shape of the flanges 24 and 25 and the flared portion 26 serve, when in the external auditory canal, to provide a relatively large resistance to movement or shifting of the earpiece ID in such canal because of a good air seal between flared portions 26 and flange 24 and also between flanges 24 and 25, and because flanges 24 and 25 are not easily deflected out of operative position when an attempt is made to remove the earpiece from the ear.
Because of the soft resilient nature of earpiece I0, only four earpieces, each suitably and differently dimensioned, are necessary to fit all but most unusually large or small ear canals.
The earpiece holder I3 is preferably made of a transparent, light and easily moulded material such as Lucite or polystyrene, which presents a pleasing appearance and in the manufacturing process is machined easily. Specifically, holder or stud I3 comprises a cylindrical portion 28 of small diameter with integrally formed flange 20 therein and a larger hollow angularly truncated cylindrical portion 29 within which there is the inner annular spring retaining groove I8.
Spring I! of spring steel, or of other suitable material having springlike properties, is split so as to be readily inserted in groove I8 of holder I3 in the manufacturing process, within which groove it is normally retained by the user so as to be in position to engage and hold resiliently the inner edge of speaker flange I9.
Speaker I5, releasably held on stud I 3 by means of resilient spring I1, is preferably of the type shown and described in the copending patent application of Gilbert E. Gustafson, Serial No. 484,153, filed April 23, 1943, and assigned to the assignee of the present invention, such speaker, or earphone, including a diaphragm movable in response to electric currents of voice frequency whereby sound pressures varying at voice frequency are transmitted through channels I4, I2 and Ii to the auditory nerves of the ear when the earphone is in operative position.
Speaker I5 shown in detail in Figs. 3 and 4 has a housing 33 with a cover 3| suitably fastened thereto, said cover having a cylindrical outwardly projecting portion 32 with an annular flange portion I9 thereon arranged to cooperate with spring member I! in holder I 3 so as to maintain speaker I5 on stud I3, from which it may be readily separated by exerting a relatively small tension force between the speaker I5 and stud I 3.
A circular sound pressure producing diaphragm 34 of magnetic material, mounted in a suitable recess 35 in housing 30, has its center portion normally attracted to the right in Fig. 4 by the magnetic flux from pole pieces 31 and 38, which flux is set up by a permanent magnet 39 having opposite magnetic poles abutting and maintaining members 31 and 38 in spaced relationship, the pole pieces 3! and 38 and magnet 39 being firmly fixed to housing 33 by a cementlike material, as explained in the above mentioned Gustafson patent application.
Diaphragm actuating coils 40 and 41, wound respectively on pole pieces 3'! and 23, are serially connected, so that a magnetic flux of voice frequency passes through the magnetic circuit including pole pieces 31 and 38, magnet 39 and the center portion of diaphragm 34 when voltages of voice frequency are applied to coil leads 44 and 45, connected respectively to binding posts 43 and 47, the binding posts 45 and 41 being fastened to the housing 3 by means of screws 48 and 49. Such magnetic flux of voice frequencies causes the inner portion of diaphragm 34 to move with corresponding frequency and amplitude whereby corresponding sound pressures are transmitted through channel I4 to the auditory nerves of the user.
A suitable dust filter 50 is carried by cover 3I and covers the opening of speaker sound channel I i, such dust filter 50 allowing sound transmission therethrough but being impervious to solid materials, so as to maintain the inner portion of speaker I5 free of dust and other foreign materials.
Because of the resilient nature, and shape of the soft. rubber earpiece. III and the shape of holder or stud I3 only four such earpieces I and four studs or holders I3 of suitably different dimensious are necessary to fit comfortably the ears. of individual adults and children difiering. in size and shape within normal limits.
In' Figs. through 8, the set of earpieces or plugs IUA, I013, I00 and IOD, having the shapes and relative sizes shown, together with the set of holders or; stud-s I3A, I33, I36 and I3D, having shapes and. relative sizes shown, allow sixteen possible combination sets, such sixteen combination. sets being sufficient to fit comfortably the ears of all adults and children differing in size and shape. within normal limits. Any one of' the earpieces HI fits on, any one of the holders or ing flange on each earpiece having a diameter 3 2 inch smaller than the corresponding flange on. the next. larger size earpiece. Also, in. each earpiece the cross section of each flange 24 or 25 is such that the soft resilient material comprising such flange is displaced more easily by contacting portions Of the car when the earpiece is inserted in the ear than is the case when the earpiece is removed from the ear. That is, each earpiece encounters moreresistance to its motion out of the auditor canal than the resistance encountered to its motion into the canal.
It is easy to insert an earpiece into the ear but it requires sufficiently greater force to remove.
that. earpiece so that the random forces encountered in the wearing of the earphone are not sufflcient to distort its position. This feature allows a particular stud I3 and speaker IE to be supported solely by engagement of the earpiece with the walls of the auditory canal.
In particular, in Fig. 5 each earpiece has a tip 25, not braced by the body portion of a connected stud when it is in operative position, and a convex faced flange which is positioned and shaped so as to be easily depressed. when the earpiece is inserted in the auditory canal and to cause considerable. resistance to motions of the earpiece when attempt is made to move it from its normal operative position in the car. This feature allows the earpiece to be inserted in the ear without discomfort and to be held firmly'therein so as to provide a good sound seal between the body of the earpiece and walls of the auditory canal when in operative position. Also, an improved sound seal is provided between the forward flange 25 and the walls of the auditory canal by the termination of the convex flange portion 25 in a substantially flat portion 55, the flat portion 55 contacting the walls of the auditory canal over a substantial area when the earpiece is in operative position.
In Fig. 5, the second flange 24 on each one of the earpieces comprising the group IDA, IIIB and H has a convex face 56 facing the forward end of the earpiece and a plane face 51 lying substantially in a plane perpendicular to the axis of the earpiece. Such shape provides that the resilient. material comprising. the second flange is" more easily deflected toward flared portion, 26 when the earpieceis inserted in operative position in. thev car than toward flange 25 when attempt is made to: remove the earpiece from such operative. position. The maximum diameter of the second flange 24 is somewhat greater than the maximum diameter of the tip flange 25 so that both flanges make suitable contact with the walls. of. the auditory canal and define a sound deadening air space between the two flanges.
The. flared. portion. 26' on each one of the earpieces IIIA, I03 and IEIC; joined to the second. flange 2'4" by-soli'd portion 23 and of different and suitable; size and shape in each earpiece comprising, a set, provides a seal for the mouth of the auditory canal. and provides a stop for limiting the distance the earpiece is inserted in the ear. Such flared portion 26 terminates in a plane 21 extending substantially perpendicular to the axis of the earpiece, which plane is substantially coplanar with the plane of the ear concha when. theearpiece is in operative position.
In Fig.5, each of the group of earpiece holdersor studs I3A, I'3B and I3C has a small cylindrical portion 28 with. an integrally formed flange 20 and a hollow cylindrical angularly truncated portion 29 having the inner annular spring retaining groove I8 therein arranged to loosely hold spring- I'I insemi-permanent position. Each of the relatively large cylindrical portions 29 shown herein is truncated at an angle of substantially 60 to the axis of the small cylindrical portion 28' as shown in Fig. 5. In each of the earpiece holders I.3A, ISB and I3C the dimensions of the smaller cylindrical portion 28 and the radial and axial thickness of flange 20 are the same. The axial length of enlarged truncated portion 29 is different in each one of the studs I3A, I313 and I3C' althoughv its outer diameter and dimensions of the spring retaining groove. I8 are the same in each one.
The front face 60 in each one of the studs I3A, I'3B and I3C in Fig. 5, when in operative position in the ear, is substantially coplanar with the plane of the ear concha. since the outer plane 21 of the earpiece II! is coplanar with that plane, and the axial dimension of enlarged portion 29 then determines the. distance that speaker I5 is displaced from the entrance to the external auditory canal. The. studs I3A, I3B and I3C have the portions 29 of such differin axial lengths as to allow suitable support of speaker I5 in relation to the geometry of individual adult ears differing within normal limits.
In other words, one of the set of rubber earpieces I DA, I03, I00 and IIJD in Fig. 5 conforms suitably to the geometry of the external auditory canal of substantially all individual ears differing in size and shape within normal limits, and one of the sets of studs or holders I3A, I3B, I3C and I3D in Fig. 5 conforms suitably to the geometry of ear portions projecting beyond the mouth of the external auditory canal such that speaker I5 may be conveniently carried on the stud I3.
In all of the earpieccs shown in Fig. 5 there are three sound seals for greatly attenuating sound pressures transmitted through the central earpiece opening II in their path back out of the ear between the outside wall of the earpiece and the wall of the ear canal so as substantially to prevent such feedback. Without such precautions, the. sound pressure fed back would influence the operation or behavior of parts of the com-- posite hearing aid apparatus which causes such sound pressures to exist. For example, in hearing aid apparatus wherein the microphone is normally mounted in relatively close proximity to the users ears, sound pressures fed back from an unsuitable earpiece influence the operation of the microphone to such an extent that a continuous singing or buzzing noise is heard by the user when listening to other sounds. This behavior is particularly objectionable when, as shown in Fig. 2, the hearing aid apparatus is provided with high gain amplifying means SI connected between the microphone J2 and sound reproducing device or speaker I In such case sound waves taking the paths 63 and 5d from the sound emitting opening II to the high gain amplifier 6i and microphone 62 respectively may cause such singing or buzzing noise to appear. In my apparatus this singing and buzzing noise effect is prevented by the previously mentioned sound seals.
Earpieces of my construction are particularly applicable for use with such high gain apparatus of the type shown in the copending patent application of John G. Prentiss, Serial N 0. 504,958, filed October l, 1943, assigned to the same assignee as the present application. The flanges 24 and 25 and flared portion 23 not only provide means for supporting a complete earphone unit in a users ear by engagement of an earpiece with the walls of the auditory canal but also provide three sound seals with an intermediate sound deadening air space between adjacent flan es and flared portions.
Fig. 2 shows a small earpiece i013 mounted on a small earpiece holder or stud 23D, such earpiece IQD and stud iIiD forming one of a set with the earpieces and studs shown in Fig. 5. Earpiece IllD and stud i3D are especially arranged for use by a child or by adults having very small ears. In such case the set of earpieces IGA, HEB, ISC and set of studs ISA, 533, I30 are available to children having somewhat larger ear canals than normal size.
In Fig. 2, earpiece MD is characterized by the fact that it has but one flange, a tip flange 25, and an integrally formed flared portion 25 joined to the tip flange 25 by a hollow conical shaped portion 66. The tip flange 25 is of soft resilient material, has a convex surface facing the forward direction and is not braced by the solid body portion of stud l3D so that it is quite resilient and enters the car without discomfort.
In order to provide a good sound seal between the body of the earpiece and the wall of the auditory canal, a beveled surface 6? of suitably large area is arranged to engage a relatively large area of the auditory canal surface so that a closed air chamber between tip flange 25 and flared portion 26 exists when th earpiece is in operative position in the auditory canal.
The flange 25 in Fig. l so formed as to be readily deflected by contact with the walls of the auditory canal when it is inserted in the ear and is not easily pulled out of engagement with such wall when random forces are encountered during wearing of the earphone, such forces tending to withdraw or shift the earpiece from its operative position.
Earpiece li'lD and stud I3D, although respectively of different shapes and sizes from earpieces IGA, I68 and IGC and studs I3A, I3B and I30, are so made that they may be readily interchanged in the set in any manner in effecting a suitable combination. That is, sixteen possible combinations are available when the set com- 8 prises the interchangeable earpieces IDA, IOB, IBC and IOD and studs I3A, 13B, I3C and I3D.
In all of the studs I3A, I3B, 13C and I3D the enlarged cylindrical portion 29 in Figs. 1 and 5 is truncated at an angle of 60. This feature allows an attached earphone I5 to be held close to the body of the outer ear structure within the space defined by the antihelix, tragus and antitragus.
It is realized that the spring I 1 shown in Fig. 1 may take forms and shapes for providing a quick releasable connection between the holder I3 and earphone I5. Fig. 8 shows a modified and preferred spring member ID arranged to be held me modified earpiece holder or stud H shown in Fig. 9.
Member 10 of resilient material has four corners l3, 14, 15 and 16 arranged to be held respectively under four small raised projections 18, I9, 88 and SI on the inner wall 82 of the stud 'II corresponding to inner wall 82 of the stud shown in Fig. l. The four raised resilient lips 83, 84, 85 and 88 of member in are arranged to resiliently and tightly hold flange I 9 of speaker I 5 in operative position, with the sound transmitting channel Id of speaker I5 in communication with sound transmittin opening I2 of stud l I. Once member if! is inserted in operative position in stud H, the relatively sharp corners l3, 14, I5 and lil penetrate to a small degree into the material comprising projections 18, "I9, ac and ill and a permanent connection between spring member 10 and holder ll exists with resilient lips 83, 84, 85 and 86 in operative position to resiliently engage flange :9 of speaker I5 so as to hold face 88 of stud II tightly against face 89 (Fig. 4) of speaker I5, with opening 99 allowing passage of sound.
In order to prevent sound energy from being transferred around the outer surface of flange I9 of speaker I5, a resilient washer 81 in Fig. 10 of small thickness and of the dimension of face 88 is interposed between speaker face 89 and stud face 88.
Fig. 11 shows an earpiece IOD and stud |3D of the types shown in Fig. l in an operative position within a human ear I90. It is seen that the tip 25 positively engages the wall I02 of the external auditory canal I63 and that the earpiece flared portion 25 seals the mouth I 04 of the auditory canal with a sound deadening space H25 between the body of the earpiece IOD and the walls I 02 of the external auditory canal.
While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader as pects, and therefore the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.
1. In combination, an earpiece of soft, resilient material having a cylindrical sound transmitting channel extending therethrough, said channel being easily closed by relatively small forces exerted on said earpiece, an earpiece holder of generally cylindrical shape having a hollow cylindrical portion thereof extending snugly into the earpiece channel sufliciently that said earpiece is held on the holder by the resilient nature of the earpiece, said cylindrical portion having a sound opening therethrough registering with said sound channel and being of such length and so disposed that the transmitting channel of the earpiece remains open when said relatively small forces are exerted on said earpiece, said holder having a hollow angularly truncated substantially cylindrical portion and a snap connector on said truncated portion arranged to connect the sound opening of the sound reproducing device with the hollow in said truncated portion and with said sound opening in said holder, in a readily attachable and detachable manner, the angle between the axis of said earpiece holder and the axis of said sound reproducing device attached at said connector being determined by the angle of truncation of said earpiece holder.
2. An adapter, including a cylindrical portion having an opening therethrough arranged to allow passage of sound and an annular ring thereon for receiving and holding open the easily closed sound opening in an earpiece of soft, resilient material, and an enlarged, angularly truncated, cylindrical portion integral with said first mentioned cylindrical portion, having an opening therethrough to allow passage of sound, the axis of said opening in said truncated portion being at an angle with the axis of the opening in said first mentioned cylindrical portion, the openings in the two cylindrical portions registering together to form a continuous sound opening, said truncated portion being provided with a snap connector ring. I
3. In combination, an earpiece of soft resilient material having a cylindrical sound transmitting channel extending therethrough, said channel being easily closed by relatively small forces exerted on said earpiece, an earpiece holder of cylindrical 10 shape having a hollow cylindrical portion thereof extending snugly into the earpiece channel such that said earpiece is held on the holder by the resilient nature of the earpiece, said cylindrical portion being of such length and so disposed that the transmitting channel of the earpiece remains open when said relatively small forces are exerted on said earpiece, said holder having a hollow angularly truncated cylindrical portion integrally formed with said first hollow portion and extending a predetermined distance away from said earpiece, a sound reproducing device having a sound transmitting channel, and means on said truncated portion arranged to hold said sound reproducing device in quickly attachable and detachable relationship and with the axis of the sound transmitting channel of the sound reproducing device displaced at an angle with the sound transmitting channel through the earpiece.
ELIZABETH L. KELSEY.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date