US 2246737 A
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Description (OCR text may contain errors)
June 24, 1941. v. o. KNUDsr-:N
EAR STOPPER Filed Aug. 7, 1959 Patented June 24`, 1941 UNITED STATES PATENT OFFICE EAR STOPPEB.
Vern 0. Knudsen, Los Angeles, Galli.
Application August 7, 1939, Serial No. 288,812
(Cl. 12S-152) 15Claims.
This invention relates to ear stoppers or ear protectors and it is a general object of the invention to provide safe, comfortable and particularly effective ear defenders or ear protectors. usef-ul by those who are subjected to heavy or persistent noises such as gun fire. riveting, detonating, machinery noises, etc., by those that are disturbed by noises or unpleasant sounds and by swimmers and others that wish to prevent the entrance of water and other material intoA the ears.
Ear stopples or protectors of various kinds have been proposed and introduced but for one reason or another have not proven effective or acceptable. The ear protectors that have been made to tightly fit the ears in order to have good sealing engagement with the walls of the auditory canal are uncomfortable, are often painful to insert and remove, and have a tendency to set up irritation in the ears. Other types of ear stopples or protectors that have been constructed to -be easily inserted and removed and to be comfortable when in place are usually ineffective in protecting the ears against loud or excessive noises or against the entrance of foreign materials.
Another object of this invention is to provide ear stoppers that are easily and painlessly inserted and removed, that are comfortable and non-irritating when in place, and that are very effective in protecting the ears against the injurious eifects of disturbing sounds and foreign materials. The ear stoppers of the present invention combine comfort with effective sound insulation and a fluid-tight closure of the auditory canals.
Another object of this invention is to provide ear stoppers embodying sets or combinations of acoustical elements related and connected to provide a substantial sound transmission loss or audio-insulation 'throughout a wide range of audible frequencies and to be comparable in their sound insulation characteristics with the anatomical structures that surround and embed the human internal ear or cochlea so that the residual sound reaching the internal ear may be limited to that which is transmitted by bone conduction or by other routes than the normal one through the external and middle ear.
Another object of this invention is to provide ear stoppers of the character mentioned embodying series of inertances or mass impedances coupled by compliances or compliance impedances to form particularly effective sound insulation networks, the said elements being constructed, related, and proportioned to make the protectors easy of insertion and removal and comfortable when in place.
Another object of this invention is to .provide ear protectors of the character mentioned in which the inertances orA at least certain of the inertances are formed of a fluid, semi-fluid, or plastic material allowing the protectors to readily conform to the auditory passages of the external ears. The inertances or mass impedance elements of the protectors provided by this invention are preferabl fluid or plastic to yield or flow when the pro ctors are placed in the auditory passages and allow'the protectors to conform to the contours of the passages Without pain or discomfort while maintaining perfect sealing con-V tact with the walls of the passages.
Anotherobject of this invention is to provide ear stoppers or protectors of the character mentioned provided with novel and very effective sealing flanges that readily conform to and seal against the walls of the auditory passage of the concha'and. external auditory meatus to fully close the same without subjecting the user to discomfort or irritation.
Another object of this invention is to provide ear protectors thatvare characteristically shaped to correctly fit the auditory passages and the entrances to the same of the average person. The shape of the protectors of the present invention is the result of an extensive study of the ears of a large number of people and the protectors of the invention are designed and constructed to properly and most effectively lit and seal with the auditory passages of the average person.
A further object of this invention is to provide ear stoppers of the character mentioned in which the fluid, semi-fluid, or plastic material or materials forming the acoustical inertances are retained or contained in novel dependable manners.
The various objects and features of my invention will be fully understood from the following detailed description of typical preferred forms and applications of the invention, throughout which description reference is made to the accompanying drawing, in which:
Fig. 1 is a side elevation of one of the ear stoppers of the present invention. Fig. 2 is a front view of one form of ear stopper of the invention. Fig. 3 is a longitudinal detailed, sectional view of the stopper shown in Fig. 2. Fig. 4 is a side elevation of an ear stopper of the invention with the forward portion broken away to illustrate one form of mass impedance means in cross section. Fig. 5 is 4a view similar to Fig. 4 illustrating another form of forward mass impedance means. Fig. 6 is a side elevation of an ear vprotector with a portion broken away to rlllustrate one form of inner mass impedance means in cross section and Fig. 7 is a view similar to Fig. 6 illustrating another form of inner mass impedance means.
The form of the invention illustrated in Figs. l, 2 and 3 of the drawing may be said to comprise,
` generally, a yielding body I closed at its inner end to have an inner part II, sealing rims or flanges I2 on the body I0, and a plug I3 in the outer portion of the body I0, constituting an acoustical impedance.
The body I0 is in the nature of a plug or stopper for the auditory passage being an elongate, generally cylindrical member proportioned to be readily entered into the passage. Where I herein employ the terms auditory passage" and auditory canal I refer to the canal of the concha and the external auditory meatus. In accordance with the invention the body I0 is tubular or hollow having a central longitudinal opening I4 extending inwardly from its outer end. An annular or continuous skirt I5 is provided on the forward end of the body I0 to engage in and seal with the chamber or space in the mouth ofthe auditory canal. The shape of the skirt I5 is important as it assures the correct fit of the protector in the ear and provides an outer or initial seal at the mouth of the auditory canal. The skirt I5 ares forwardly and laterally and has a rather thin wall to most effectively conform to the configuration of the ear. The upper portion of the skirt I5 has a margin or edge that is generally concentric to the longitudinal axis of the body I0 while the lower portion of the skirt I5 is excentric or lobe-like.
The part II closes the inner end of the hollow body I0 and acts as an inertance element as well as a closure for the body. The part I I may be an integral wall of the body and its external surface is convex or partially spherical to assist in guiding the protector into the auditory canal. In the particular form of the invention illustrated in Fig. 3 the wall thickness of the part II is comparable with that of the other portions of the body I0, it being understood, however, that the part II may have a greater wall thickness to be more effective as an inertance. The inner end portion of the body I 0 adjacent the part II. is preferably slightly reduced in diameter. The body I0 just described is preferably an integral member formed of soft gum rubber or its equivalent and is soft, pliable, and flexible and possesses considerable resiliency.
The sealing rims or flanges I2 are provided to seal with the walls of the auditory canal and are of such character and formation that they produce very eifective seals without causing discomfort to the user. There is preferably a plurality of spaced annular or continuous flanges I2 on the body I0. In the typical case illustrated there are two longitudinally spaced flanges I2. One flange I2 is arranged at the inner end of the body I0 to have its in'wardly facing surface constitute a continuation of the spherical external surface of the body part II. The second flange I2 is spaced some distance outwardly from the first mentioned flange I2 and is spaced -a considerable distance from the outer end of the body I0. The flanges I2 have laterally and forwardly curved front and rear surfaces and are tapered in cross section to terminate at rather thin marginal edges. The flanges I2 are formed and proportioned so that their cooperation with the wall of the auditory canal of an average ear results in their fiexure so that they lie against or in close proximity to the surface of the body I0. As illustrated in the drawing the flanges I2 may be integral parts of the body III and in any case are flexible, yielding, and resilient.
The resiliency of the flanges i2 urges the flanges outwardly into effective sealing engagement with the walls of the auditory canal to provide spaced lines or zones of sealing contact with the wall of the auditory canal. The spaced flanges I2 may leave an air space in the auditory canal in surrounding relation to the body I@ and the spaced outer flange I2 and skirt I5 may leave a similar space, the spaces acting to improve the effective sound insulation of the protectors. The flanges I2 are adapted to enter and fit the varied shapes and contours often present in the auditory canal, to assure the correct engagement of the protector in the canal. While the ear protectors herein described are designed to iit a wide variety of shapes and sizes of ears it may be found desirable or necessary to provide two or more sizes and to make certain modifications in respect to the shape to suit all ears, including such modifications as may be found necessary or desirable to make the ear protectors in pairs for use in the left and right ears. IIlhe cooperation of the skirt I5 with the mouth of the auditory canal assists in providing effective fluid tight seals and assures the proper retention of the protector.
The plug I3 is an inertance element arranged in the forward portion of the body I0. In practice the plug I3 is a closure for the forward end of the body opening I4. The plug I3 is of sufficient size and mass to form an effective imped.
ance orA inertance and is preferably formed of a.
material having a substantial specific gravity. For example, the plug I3 may be formed of brass, bronze, copper, ferrous metals or suitable alloys of such metals. It is also contemplated that the plug I3 may be formed of hard rubber, ebony, ivory, a thermoplastic, or Athe like. As best illustrated in Fig. 3 of the drawing the plug I3 may be a generally cylindrical block-like part entering the outer end of the body opening I4. The plug I3 is suitably secured in the flexible yielding bodyv I0. In the case illustrated an annular flange I6 is provided on the plug I3 and cooperates with a groove II in the wall of the opening I4 to retain the plug in place. The flange I6 is preferably spaced between the ends of the plug I3 so that a substantial portion of the plug extends inwardly beyond the flange. The body of the plug I3 is preferably of less diameter than the opening III to have substantial clearance with the wall of the opening. This allows the body I0 to flex or compress with little or no interference from the plug I3. The plug I3 preferably projects from the forward end of the body I0 to have its forward part within the cupped skirt I5.
'I'he plug I3 may have an annular flange or knob I8 at its outer end to be grasped by the user when inserting and removing the protector. The rigid plug I3 set or positioned in the forward portion of the body I0 lends considerable rigidity to the protector without appreciably interfering with the fiexure of the body.
In the use or operation of the improved ear protectors, a protector may be inserted in the auditory canal of each ear to protect the ears against intense or undesirable sounds or to prevent the entrance of materials into the ears.
When a protector'isA entered in an ear passage the flanges I2 are bent or flexed toward the; external surface of the protector body I and the skirt l may be contractedto some extent through engagement with the chamber at the mouth of the auditory canal. 'I'he flanges I2 seal outwardly against thewall of the auditory canal through their inherent resiliency providing spaced dependable-seals without scratching, irritating, or exerting excessive pressure to the walls of the auditory canal. 'I'he soft, readily deformed, re-
. silient flanges l2 conform to al1 irregularities of the auditory canals and each has full and most effective sealing engagement with the walls of the canal throughout its circumference. The lobe-like lower portion of the skirt I5 usually readily cooperates with the lower portion of the chamber in the external ear adjacent the opening of the auditory canal but a slight turning of the protector about its longitudinal axis may in some cases facilitate the complete closure of the canal.
The ear protector described above is a particularly efficient sound insulation unit. The dense metal plug Il constitutes an emcient inertance element and has a very small acceleration or displacement imparted to it by the force of the incident sound waves, explosion waves, or the like. The wall of the yielding body I0 forms a loose coupling or acoustical compliance. The metal plug I3 and the soft yielding body l0 constructed and combined as described above transmit or communicate only a small fraction of the sound energy that reaches the protector. The inner wallv part II of the .body Ill constitutes an inertance and being formed of a soft yielding material may also act as a compliance. ever, in some cases the wall ll may be of substantial thickness to operate principally as an acoustical inertance. In general the parts I2, l0 and Il are acoustical elements having inertance, compliance and resistance respectively. By varying the size and mass of the plug 13, the yieldability of the body l. and the thickness, mass and yieldability of the part H, the sound transmission and insulating characteristics of the protector may be altered to adapt the device or protector for practically any use. The protector assures a transmission loss or sound insulation of a high ratingthroughout a wide range of audible frequencies.
Figs. 4 and 5 of the drawing illustrate forms of outer or forward inertances that may be embodied in the protector of the invention. In the construction illustrated in Fig. 4 of the drawing the body l0* has a forward wall 2l closing the forward end of its opening Il.. The forward body wall 2li is o f substantial thickness and may be of the same material as the body I0". In accordance with the invention a space or chamber 2l is provided in the wall 2l. 'lhe chamber 2| is of substantial depth and is preferably of substantially the same diameter as the opening Ih. A fluid, semi-fluid or 'plastic material 22 is contained in the chamber 2l. In practice the material 22 is preferably mercury to be highly efcient as an inertance means. The wall 2l may have a knob 23 useful in inserting l,and removing the protector. The wall 2l may be wholly or partially formed separate from the body Ill to facilitate the introduction of the material 22 to the cham- HOW- tector illustrated in Fig. 4 may be the same as in -same function as the plug I3, that is, it serves as an inertance, The material 22 being liquid does not resist ilexure or distortion of the protector and allows the protector to conform to auditory canals of practically any shape and configuration. The liquid material 22 remains fully operative following distortion or flexure of the body IIIn resulting from its insertion in the auditory canal. It will be observed that the liquid material 22 of a high specific gravity is surrounded by and is in direct contact with the soft yielding material of the body wall 20 so that the structure provides the combination of an eicient inertance means contacting and surrounded by compliance.
The form of the invention illustrated in Fig. 5 comprises a plug element 25 arranged in the forward portion of the body opening Hb. The plug element 25 may be formed of rubber, or the like, that is iiexible and resilient but somewhat less yielding than the material of the body l0". The plug element 25 may be secured in the body lub in any selected manner as by cementing, vulcanizing, etc. In the construction illustrated the plug element 25 has 'an annular flange or bead 26 set or secured in a groove 21 in the wall of the opening |41. The bead 26 may be partially circular in cross section to have interlocking engagement with the groove 21. In accordance with the invention the plug element 25 is hollow, being provided with a cavity or chamber 28. 'I'he cavity 28 contains a plastic, fluid or semi-fluid material 29 which serves as an ber 2| or, if desired, the material 22 may be introinertance. I prefer to employ mercury as the material 29. The chamber 28 is preferably of substantial diameter and depth to contain a considerable volume of the inertance material 2l although the proportions of the chamber 28 may be varied to suit different applications of the invention. A handle or knob 30 may project outwardly from the plug element 25.
The ear protector shown in Fig. 5 of the drawing embodies a plug element 25 containing or carrying an inertance means that yields to allow iiexure and distortion of the protector structure. In some instances the plug element 25 may distort or change its shape when the body Nb of the protector is positioned in the auditory canal and the material 29 being fluid does not resist this change in configuration but changes itsv shape with the distortion of the plug element. 'Iihe novel inertance of the structure shown in Fig. 5 of the drawing offers little or no resistance to change in the shape of the protector so that the protector is safe and comfortable even though distorted to an appreciable extent when in its operative position.
Figs. 6 and 7 of the drawing illustrate inertances arranged in the inner portions of the protector bodies. The inertance means shown in these figures may be vembodied in any of the previously described constructions as conditions may require or warrant.
In the construction shown in Fig. 6 the inner part llc of the body I 0 is provided with an internal or ,forwardly projecting knob 32. A rib or flange 33 is provided on the wall of the body opening Ilc in spaced relation to the part Ii. A body or mass 34 of a plastic material is provided in the inner part of the yopening I4 and is normally retained in position by the knob 32 and the ilange l33. The mass 34 may be any suitable material that is plastic or formable at body temperatures. I have found that a mixture of wax, resin, and turpentine constitutes a suitable material for the mass 34 although such materials as latex, soft rubber, synthetic plastics, etc., may be employed. The mass 34 is introduced to the opening l4 and is pressed in the,
that the mass 34 flows back to its operative position. The plastic or semi-plastic mass 34 contained in the inner portion of the body I0 is eflicient as an inertance. The mass 34 is formable and yields so that it allows the adjacent portions of the protector to flex and distort when the protector is arranged in place in the auditory canal or passage. When the mass 34 is used in conjunction with the plug I3 or the materials 22 or 29, described above, the protector embodies a particularly effective acoustical network consisting of an outer inertance, an inner inertance and a compliance connecting the two inertances.
The construction shown in Fig. 7 of the drawing includes an inner body part Ild provided with a space or chamber 35. 'Ihe external configuration of the part I Id may be the same as that of the part Il described above, and the part Ild may be a continuation of the adjacent parts of the body Illd. The chamber 35 contains a formable or fluid material 36 that serves as an inertance means. The material 38 may be any material of substantial specific gravity that is iluid or plastic to oier little or no resistance to exure and distortion of the adjacent parts of the protector. In practice the material 36 may be mercury. As shown, the chamber 35 may be of substantially the same diameter as the body opening I4d and may be of substantial depth. 'I'he material 36 operates in the same manner as the mass 34 described above constituting an inner inertance means and coupled with the outer inertance by the compliance or yielding body Walls. The material 36 may be introduced into the chamber 35 in any practical manner, and the body part lid may be formed integral with the body I0", may .be in part integral with the body Illd or may be a separately formed unit similar to the plug element 25 of Fig. 5, vulcanized or otherwise secured to the body.
Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.
Having described my invention, I claim:
1. An ear protector comprising a body to be inserted in the auditory passage and formed of yielding material, and a liquid inertance element carried by the body.
2. An ear protector comprising a yielding body to be inserted in the auditory passage, and a mass of fluid material of substantial specific gravity in the body forming an inertance.
inserted inl the auditory e, and a exible resilient sealing flange on the body having a convex entering side and a. concave trailing side to readily contract toward or against the body through contact with the internal wall of the passage when the body is inserted, the ange being adapted to seal with the said wall through its resiliency.
4. An ear protector comprising a body to be inserted in the auditory passage, and a yielding resilient sealing ilange around the body, the trailing and entering sides of the iiange sloping laterally and rearwardly relative to the entering end of the body so that the iiange contracts through engagement with the internal wall of the passage when the body is inserted, the trailing side of the flange being in outwardly converging relation to said entering side, the ange operating to seal with the wall ofl through its resiliency when so contracted.
5. An ear protector comprising a body to be inserted in the auditory passage, and a plurality of longitudinally spaced resilient sealing iianges around the body, the forward faces of the flanges sloping laterally and rearwardly relative to the entering end of the Ibody so that the iianges contract through engagement with the internal wall of the passage and seal with the wall of the passage through their resilienc the rear faces of the flanges being concave to render the flanges more yielding.
6. An ear protector hollow body to be inserted in the auditory passage to form an acoustical compliance, a liquid mass of substantial specific gravity contained in one end portion of the body forming an inertance, and means retaining said mass in said end portion ofthe body and allowing exure and disi tortion of the body.
7. An ear protector comprising a yielding body to be inserted in the auditory passage to form an acoustical compliance, the body having a longitudinal cavity, an inertance means at the outer end of the cavity, a wall across the inner end of the cavity, a dense inertance canied by said Wall, and a sealing flange on the inner portion of the body forming a continuation of said wall and flaring rearwardly relative to the entering end of the body to contract through contact with the wall of the passage.
8. An ear protector comprising a yielding body to be inserted in the auditory passage to form a compliance unit, the body having a longitudinal 3. An ear protector comprising a body to be opening, a yielding plug closing an end of the opening and having a closed chamber, and iiuid of high specic gravity in the chamber forming an inertance.
9. An ear protector comprising a yielding body to be inserted in the auditory passage to form an acoustical compliance, the body having a longitudinal cavity, an inertance means at the outer end of the cavity comprising a metal plug in the outer end of the cavity, a yielding wall' spaced inwardly from the plug for closing the inner end of the cavity forming an inertance and presenting a convex external surface at the inner end of the body, and a flaring yielding flange on the inner portion of the body for sealing with the wall of the passagethe surface of the ilange forming an even continuation of the iirst named surface. y
l0. An ear protector comprising a yieldingfbody adapted to be inserted in the auditory passage to form an acoustical compliance, the bodyf'havmg substantially 1ongitudina1ly aligned entities,
the passage comprising a yielding and fluid material in at least one of the cavities forming an inertance.
1 l. An ear protector comprising a yielding body adapted to be inserted in the auditory passage to form an acoustical compliance,the body having substantially longitudinally aligned cavities, and mercury in one of said cavities forming an inertance.
12. An ear protector comprising a yielding body adapted to be inserted in the auditory passage to form an acoustical compliance, the body having an inner longitudinal cavity and an outer cavity, and a dense fluid material in the outer cavity forming an inertance.
13. An ear protector comprising a yielding body adapted to be inserted in the auditory passage to form an acoustical compliance, the body having aligned inner and outer cavities, and a dense Iiuid material in the inner cavity forming an inertance.
14. An ear protector comprising a yielding body adapted to be inserted in the auditory passage to form an acoustical compliance, the body being hollow and provided with spaced transverse yielding walls dividing its interior into closed cavities, and a fluid of high specific gravity in at least one of the cavities forming an inertance.
l5. An ear protector comprising a yielding hollow body to be inserted in the auditory passage to form a compliance unit, a mass contained in one end of the hollow body comprised of a material which is fluid at body temperature, and means for retaining said mass in said end of the body comprising a projection on the interior of the body extending into said mass.
VERN 0. KNUDSEN.