US 3301253 A
Description (OCR text may contain errors)
Jan. 31, 1967 A. GLORIG EAR PROTECTOR Filed Jan. 21, 1965 f .3 I NVEN'TOR.
41 4M 6102/5 BY Jrraewsy United States Patent M 3,301,253 EAR PROTECTOR Aram Glorig, 5539 Sarquhar Lane, Dallas, Tex. 75214 Filed Jan. 21, 1965, Ser. No. 427,037 6 Claims. (Cl. 128152) This invention relates generally to acoustical attenuator devices for use as car protectors by those working in the vicinity of sources of high intensity sound, such as jet engines, noisy industrial machinery, such as machine hammers, riveters and the like, and for use also by sportsmen who spend considerable time at target practice with guns.
Ear protectors have been provided in the past in considerable number and variety. They have been usually in either of two classes, plugs adapted for insertion into the ear canal, and muffs covering the ear. The muff types generally employ a headband which presses the muffs against the sides of the head over the ears. A few attempts have been made to provide a third class, involving a closure for the entrance to the external ear, pressed .in place by a headband. Some of these ear protectors have, of course, contributed a considerable degree of protection to the ear, though, in general, in every instance of which I am aware, still leaving something to be desired.
The ear protector of the present invention is of the third class mentioned above, and objects of the invention are to provide improvements in this type of ear protector as regards the amount of noise reduction attained, comfort to the wearer, easy and inexpensive replaceability of worn parts, safety to the wearer, natural close-fitting accommodation to the external ear canal opening and automatic guarding against displacement therefrom through such activities as chewing or talking, and accommodation of the headband to glasses and/or a hard hat worn by the user.
The invention will -most easily be understood by referning at once to the following detailed description of a present, illustrative embodiment thereof, in the course of which the various features of improvement and advantage inherent in the invention will be stressed. In the drawings, showing this illustrative embodiment:
FIG. 1 shows a face view of a man wearing the ear protector of the invention, the ear canal being shown in section;
FIG. 2 is a side elevational view of the ear protector of the invention with the headband in contracted position;
FIG. 3 is a longitudinal sectional view of the assembled plug and retainer of the ear protector, together with a' portion of the headband, showing the latter in the position assumed when in use;
FIG. 4 is an elevational view taken in the aspect of the numeral 4 in FIG. 3;
FIG. 5 is a detailed section taken on line 55 in FIG. 2;
FIG. 6 is a view taken in accordance with the section line 66 in FIG. 3;
FIG. 7 is a 'view similar to FIG. 6 but showing a modification; and
FIG. 8 is a view similar to FIG. 6 but showing a modification.
The protector comprises a pair of plugs 10, a plug holder or retainer 11 for each plug, and a resilient metal headband 12 connected to each plug.
The plugs are molded of soft, pliable, rubber-like material, such as neoprene or the like, and a Shore hardness of 9 is preferred. Each plug comprises a head or stopple 13, and a reduced cylindrical stem 14 integral 3,301,253 Patented Jan. 31, 1967 with and extending therefrom. The diameter of stem 14 is roughly comparable with the size of the entrance to the ear canal. The head 13 is generally conical, which can be modified by a slight convex curvature, as seen in profile. The somewhat pointed apex of the head of the present embodiment is of no particular significance. As seen in end elevation (FIG. 4), the head is somewhat elliptical, having a greater major vertical dimension than its minor horizontal dimension. The head angle in the illustrative embodiment may be said to be slightly obtuse in the narrow aspect of FIG. 6, and more obtuse in the wider aspect of FIG. 3. Alternatively, the point of the cone can be rounded off, and the plug given a more rounded or convex profile, as seen in FIG. 8. Contouring as thus described nicely accommodates the head to the natural entrance opening to the external ear canal.
The head 13 will be seen to be undercut at 15, so that outside of the stem 14, the head comprises a soft and nearly limp outwardly tapering wall portion or lip 16.
The plug holder or retainer 11 comprises an integral mounting disc 18 and a reduced coaxial stem or sleeve 19, an axial bore 20 extending through the disc 18 and sleeve 19. The internal diameter of the bore 20 is typically inch less than the normal outside diameter of the plug stem 14, and the stem 14 is installed in the bore 20 by longitudinally stretching the stem 14 to reduce its diameter. This may be accomplished by any device, such as long nosed tweezers, projected through the bore 20 and then clamped onto the extremity of the stem 14, the head 13 being restrained while the stem 14 is stretched out sufliciently to slide easily into the described bore in the retainer. The plug is thus installed in the retainer, with the end of the reduced retainer sleeve 19 engaged against the rearward side of the head wall 16.
The retainer 11 is preferably also molded of a rubberlike material, such as neoprene, and is compounded to greater hardness than the plug 10. A Shore hardness of 30 is preferred. There are several reasons for the difference in hardness between the plug and the plug retainer, as will be brought out presently.
As will appear from FIG. 1, the soft, pliable head part 13 of the plug is designed to engage the shoulder 30 of the ear structure around or at the entrance to the external ear canal 31. The shoulder will be seen to indent the soft head 13. The head part 13 is soft enough and yield-able enough at Shore 9 to conform to and fill the small surface irregularities and crevices around the entrance to the ear canal with a substantially air-tight fit when pressed inward toward the ear canal with a pressure which is well within the level of easily acceptable comfort. The rather extreme softness of the member 13 thus affords the desired} substantially air-tight fit. It also serves for maximum comfort, in view of its instant and complete accommodation to the shape of the ear parts which it contacts. Still further, it serves to protect the ear by functioning as an inner cushion in the event that a blow should be received by parts of the protector outside. Moreover, the soft stem 14, of course, is so flexible as to be incapable of transmitting injurious blows or shocks to the head 13 and thence to the ear.
The retainer 11, at Shore 30, is also soft and yieldable enough to protect the ear against dangerous injury in case of a blow received thereagainst. It has, at the same time, sufficient stiffness to be capable of transmitting adequate pressure to the soft head 13 for attainment of the necessary tightness of closure pressure between said head and the ear canal.
In the manufacture of the ear protector, once the stem 14 has been inserted inside the retainer, the lower shank 40 of a headband 12 is inserted transversely and diametrically through the enlarged retainer disc 18 and the plug stem 14. The headband is preferably composed of two arcuate strips 12a and 12b of stainless spring steel, telescopically overlapped, as indicated, and of a width of approximately a quarter inch, which is a dimension just a little under the diameter of the ear plug stem 14. A diametrical slot is preliminarily formed in the retainer disc 118 for tight reception of the headband shank 40 and when the shank 40 is forced on through the disc, it punctures the soft stem 14 and slides through it. Thus, in the final assembled form of the ear protector, the stem 14 is locked in its proper operating position relative to the retainer 11 by the headband 12.
The headband shank 40 is bent inwardly at 41, a short distance above the ear, and also above the level of the bows of a potential wearers glasses (so as to clear such bows), through an angle preferably of a little greater than 90 (when the headband is relaxed, as in FIG. 2), so as to form a short inwardly offset shank portion 42. The bow of a pair of glasses is indicated at b, on the left side in FIG. 1, in the space left by the described shaping of the headband. At the inner end of each such offset shank portion 42, the band is bent upwardly, through nearly or substantially 90, and is then shaped into a curve, as illustrated. The thus curved portions 44 of the headband are slidingly overlapped for adjustment purposes, and encased in a vinyl sleeve 46, as indicated. It will be appreciated that the headband has been resiliently sprung outwardly in the position of FIGS. 1 and 3, and exerts spring pressure on the retainers 11, which in turn press the ear plug portions 13 tightly into the ear canal entrance openings. It will also be appreciated that normally the headband assumes a contracted relaxed position with the plugs and retainers close to one another, as in FIG. 2. The location of the inner ends of the offset headband portions 42 relative to the forward extremities of the ear plugs is important, since the pressure exerted by the headband must be exerted through the retainers and plugs against the ear openings, and therefore the band portions 42 must not be so long that the band engages the sides of the wearers head. If such should be the case, the necessary pressure between the plugs and the ear openings would be prevented.
Attention is further directed to the fact that the headband is also shaped, however, to conform relatively close- 1y to the wearers head above the ears, so as to avoid interference with the wearing of a hard hat.
The ear protector of the invention has proved to be very effective in attenuating high intensity sound. One acoustically based reason for this attainment in the case of the present device is the softness and consequent low acoustic impedance of the plug component 10. The retainer 11 is of higher acoustic impedance, though still low; and, of course, the steel headband is of high acoustic impedance. Accordingly, sounds picked up by the headband are not, because of high mismatch of impedance, transmitted in any material degree to the retainer 11. The differences in hardness between the retainer and the ear plug are also sufficient to afford a considerable impedance mismatch at their junction. Accordingly, to whatever extent the retainers may be set into sound wave vibration or transmission from external sound sources, such waves are substantially reflected back at the interfaces with the soft plug, and not transmitted into and through the plug and thus into the ear.
The ear protector as thus described is held firmly but comfortably in position in the ears, and is not displaceable by jaw movements, such as in talking or chewing. It affords excellent acoustic protection to the ear, and at the same time has been contrived to safeguard the ear against injuries from blows received against the protector, as mentioned hereinabove. In case of wear, injury or deterioration of a retainer or plug by age, the retainer can be easily pulled off the headband shank and replaced by a new unit.
In the device as disclosed hereinabove, the headband shanks and the retainers are assumed to press the ear plugs straight towards one another. Certain further improvements can be incorporated whereby the ear plugs are pressed a little forwardly, or at a small forward angle, so as to conform still better to the fact that the normal ear canal opens to the outside on a slightly rearwardly inclined axis. This can be accomplished by putting a slight twist in each headband member, such as to incline each retainer into closer alignment with the ear canal axes. Such a slight twist is too small to illustrate easily in the drawings, and is therefore omitted. A preferred alternative, shown in FIG. 7, is to avoid twists in the headbands, which are difficult of accomplishment in any event, and to insert the headband shanks 40 through the retainers on a slight angle, as clearly illustrated, whereby the same result is accomplished.
The invention has now been illustrated in a present preferred form. It will be understood, of course, that this presently preferred form is illustrative only and that various changes in design, structure and arrangement may be made without departing from the spirit and scope of the appended claims.
1. An ear protector, comprising:
an ear plug of relatively soft, yieldable, rubber-like material comprised of a head engageable with the entrance to the auditory canal, and an integral reduced stem extending outward from said head, and
a retainer of harder, yieldable, rubber-like material fixed on said stem and including a sleeve surrounding said stem and abutting and supporting the outer side of said head.
2. The subject matter of claim 1, wherein said plug has a Shore hardness of the order of 9, and said retainer has a Shore hardness of the order of 30.
3. The subject matter of claim 1, wherein said head is generally elliptically shaped in planes transverse to said stem.
4. The subject matter of claim 1, including also means for yieldingly pressing said retainer toward the ear of the user.
5. In an ear protector, the combination of:
a pair of ear plugs of relatively soft, yieldable, rubberlike material each plug comprising a head engageable with the entrance to the auditory canal, and an integral reduced stem extending outward from each head,
a retainer for each of said plugs of harder, yieldable,
rubber-like material, embodying a head and an integral sleeve each extending therefrom, said heads and sleeves having an axial bore which is dimensioned to tightly receive said stems, with the ends of said sleeves abutting said heads, and
a resilient headband having shank extremities which penetrate and are frictionally gripped by said retainer heads and said ear plug stems and which lock said retainers to said stems.
6. The subject matter of claim 5, wherein said shank extremities are arranged to position said ear plug stems on axes which are inclined slightly forwardly of a straight line extending between said ear plugs.
References Cited by the Examiner UNITED STATES PATENTS 2,670,737 3/1954 Cantor 128152 3,016,054 1/1962 Rosenblatt l28152 3,160,717 12/1964 Beguin 179182 ADELE M. EAGER, Primary Examiner.