US3593341A

US3593341A - Sound-attenuating earcups

Info

Publication number: US3593341A
Application number: US219A
Authority: US
Inventors: Jackson A Aileo
Original assignee: Gentex Corp
Current assignee: Gentex Corp
Priority date: 1970-01-02
Filing date: 1970-01-02
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20

Abstract

A sound-attenuating earcup device adapted for use either with or without a safety helmet, comprising a rigid cup with a resilient seal attached to the rim of the cup. The seal has an annular surface for engaging the wearer''s head, and has a dimension between the cup rim and the outermost head-engaging portion of this surface that varies around the periphery of the cup in accordance with the contours of a human head. In one form, the surface of the seal which comes into contact with the wearer''s head includes inner and outer flanges defining a channel having diverging side flanges. When the seal is pressed into engagement with the side of the wearer''s head, the flanges spread apart and the material between the flanges is stressed in tension, thereby improving the effectiveness of the seal at the flanges and, hence, the sound-attenuating properties. The outer flange is contoured to follow the contours of a human head. A tortuous, pressure-equalizing, sound-attenuating fluid path is provided through the wall of the earcup, for use in situations where the ambient pressure is subject to variation. In another form, the seal has a wide contact surface arranged to engage the wearer''s head essentially continuously between its outer and inner annular edges; the contact surface, which may be smooth or corrugated, slopes inwardly toward the center of the earcup with a pitch that varies around the cup to follow the head contours.

Description

United States Patent [72] Inventor Jackson A. Aileo Carbondale, Pa. 21 Appl No 219 [22] Filed Jan. 2, 1970 {45] Patented July 20, 1971 73] Assignee Gentex Corporation Carbondale, Pa. Continuation-impart of application Ser. No.

730,264, May 20, 1968, now abandoned.

[54] SOUND-ATTENUATING EARCUPS 21 Claims, 20 Drawing Figs. [52] US. Cl 2/209, 179/ 182 [51] Int. Cl A42b 1/06 [50] Field of Search 2/209, 174, 6, 3,8; 128/152; 179/156, 182; 181/31,23

[56] References Cited UNITED STATES PATENTS 1,367,746 2/1921 Kent 179/182 1,527,802 2/1925 Huggins 179/182 2,468,721 4/1949 Volkmann.... 179/182 2,593,892 4/1952 Kindel 181/31 2,946,860 7/1960 Jansen et a1. 179/156 3,026,524 3/1962 Bixby 2/6 3,220,505 1 1/1965 Hargrave 181/23 FOREIGN PATENTS 796,004 1/1936 France 2/209 1,341,336 9/1963 France 2/209 Primary Examiner-Jordan Franklin Assistant Examiner--George H Krizmanich AttorneysChristopher C i Dunham, Robert S. Dunham, P. S. Henninger, Lester W. Clark, Thomas F Moran, Gerald W Griffin, Howard J. Churchill, R. Bradlee Boal and Robert Scobey ABSTRACT: A sound-attenuating earcup device adapted for use either with or without a safety helmet, comprising a rigid cup with a resilient seal attached to the rim of the cup. The seal has an annular surface for engaging the wearers head, and has a dimension between the cup rim and the outermost head-engaging portion of this surface that varies around the periphery of the cup in accordance with the contours of a human head. In one form, the surface of the seal which comes into contact with the wearers head includes inner and outer flanges defining a channel having diverging side flanges. When the seal is pressed into engagement with the side of the wearers head, the flanges spread apart and the material between the flanges is stressed in tension, thereby improving the effectiveness of the seal at the flanges and, hence, the sound-attenuating properties. The outer flange is contoured to follow the contours of a human head. A tortuous, pressureequalizing, sound-attenuating fluid path is provided through the wall of the earcup, for use in situations where the ambient pressure is subject to variation. In another form, the seal has a wide contact surface arranged to engage the wearers head essentially continuously between its outer and inner annular edges; the contact surface, which may be smooth or cormgated, slopes inwardly toward the center of the earcup with a pitch that varies around the cup to follow the head contours.

PATENTEU JUL20 |97i SHEET 3 OF 3 SOUND-ATTENUATING EARCUPS CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of applicants copending US. Pat. application, Ser. No. 730,264, filed May 20, 1968 now abandoned for Sound-Attenuating Earcups.

BACKGROUND OF THE INVENTION This invention relates to sound-attenuating earcup devices, such as those worn by personnel working in environments where protection of the ears from ambient noise is necessary, In many such environments a protective helmet is also highly desirable. Consequently, it is desirable for the earcups to be adaptable for wear either with a safety helmet, or with some other suitable supporting structure. Whether the supporting structure is a helmet or not, it is commonly provided with some means for pressing the earcup against the wearers head. A resilient sealing pad is mounted on the rim of the earcup, so as to engage firmly and resiliently the human head in the area about the ear. The pressing means and the resilient pad are intended to cooperate in closing all leakage paths by which ex ternal sound waves might reach the wearer's ear.

Certain persons have duties to perform in environments subject to high-intensity sounds, e.g. in the vicinity of jet engines. As the engine power outputs become greater, the sound intensities encountered increase, creating a demand for more effective sound-attenuating devices.

The attemptsto meet this demand have inthe past taken one or both of two directions. One direction has been to increase the force of the pressing means to close more completely the sound leakage paths. The other direction has been to increase the mass, or the volume, orthe flexibility of 3 5 SUMMARY OF THE INVENTION The present invention resides in a novel sealing pad mounted on the rim of the earcup and so constructed as to close substantially all leakage paths, thereby attenuating external sounds to a degree greater than has heretofore'been attained, with a relatively light pressure against the wearer's head.

To this and other ends, the invention broadly contemplates an earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearers ear, including a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from the shell anddefining an elliptically annular opening into the shell interior, dimensioned to surround the wearer's ear, and a softly resilient sound-attenuating pad adapted for engagement with the wearer's head along an area encircling the wearers ear, and having a particular contoured configuration ashereinafter. described.

More specifically, in accordance with the invention, and as a particular feature thereof, the sound-attenuating pad comprises an elliptically annular base having one side engaging the plane surface of the shell rim, and anelliptically annular sealing portion projecting from the base in a directionaway from the aforementioned one side, and having a sealing surface for engaging the wearers head with elliptically annular outer and inner peripheries surrounding the opening and being spaced.

apart substantially equidistantly from each other at all points around the periphery of the opening, wherein the sealing portion has a dimension between the rim-engaging base and the sealing surface outer periphery which varies around the periphery of the earcup, thisdimension increasing rapidly toward the front from the top toa first maximumin the front portion of the sealing surface outer-periphery, then decreasing gradually to a minimum adjacent the bottom, then increasing upwardly toward the back to a maximum in the rear portion of the sealing surface outer periphery and then decreasing gradually to another minimum adjacent the top.

In one form of the invention, the novel resilient sealing pad includes three distinctive features. Any of these features may beused alone, but best results are secured by using them all.

One of the features is the transverse cross-sectional contour of the pad. The head-engaging surface of that contour has a broad channel shape, with divergent flanges at the sides of the channel, the flanges terminating in smoothly curved surfaces. Those surfaces engage the wearers head first when the earcup is put in place, and are spread apart by the force of that engagement. This spreading stretches the material at the bottom of the channel, and this tensioning of the resilient material is effective to hold the flanges of the channel firmly against the wearers head.

Another feature is the contour of the profile of the outer flange. This contour follows the average humps and hollows of ahuman head along a path encircling the ear. Two specifically different contours for the outer flange are disclosed, and others are suggested.

The head-engaging surfaces of the outer and inner flanges respectively constitute the outer and inner peripheries of the pad sealing surface (which also includes the channel) in this embodiment, and the two flanges themselves comprise the sealing portion of the pad. Thus the outer flange is contoured in accordance with the sealing portion dimension described above.

Pressure-equalizing structures are illustrated which allow the pressure within the earcup to follow variations in the ambient pressure. The airflow paths in these pressure-equalizing structures are tortuous so that sound waves moving through these pads are attenuated, even. though the flow of air is sufficientlyrapid to equalize the pressures.

' In one modification, a coil spring is molded into the periphery of a flange on the sealing pad which engages the outer side of the earcup. The spring length is selected so that the spring is stretched when the sealing pad is in place on the earcup. The spring is thereby effective to hold the sealing pad in place.

In another form of the invention, the sealing surface of the pad extends substantially rectilinearly from any given point on the outer periphery thereof to the nearest adjacent point on the inner periphery thereof, and slopes inwardly with respect to the axis of the earcup shell, toward the shell opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of the maxima and minima of the sealing portion dimension between the rim-engaging base of the pad and the outer periphery of the sealing surface.

In a modification of the last-described embodiment, the sealing surface may be corrugated, with plural parallel elliptically annular ribs defining plural parallel elliptically annular grooves between them.

In each of the described embodiments, the aforementioned varying dimension of the sealing portion, in combination with either the flange and channel arrangement or the inwardly sloping sealing surface, affords substantial conformity of the seal to the hump-and-hollow contours of the average human head, and thus enables attainment of sealing engagement between the pad and the wearers head in a region completely encircling the ear, without gaps that might provide paths for transmission of sound, notwithstanding minor variations in head'contour between one wearer and another; and at the same time, again because of the generalized head-conforming contour of the pad, this desired sealing engagement is achieved with advantageously light pressure on the earcup.

Further features and advantages of the invention will be apparent from the detailed description'hereinbelow set forth, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a vertical sectional view taken along the centerline of an earcup embodying the invention, looking toward the front;

FIG. 2 is a vertical sectional view taken along the centerline of the earcup of FIG. 1, but looking toward the rear;

FIG. 3 is a fragmentary cross-sectional view, illustrating the position of the flanges when the seal is pressed against the wearer's head;

FIG. 4 is a fragmentary view illustrating a modification of the seal attached to the earcup;

FIG. 5 is a fragmentary view illustrating a further modification of the seal;

FIG. 6 is a fragmentary view illustrating a modification in the contacting surface of the seal;

FIG. 7 illustrates on an enlarged scale a pressure-equalizing device which may be used with the earcup of the present invention;

FIG. 8 illustrates, also on an enlarged scale, a modified form of pressure-equalizing device;

FIG. 9 is a fragmentary elevational view ofa modified form of earcup looking from the sealing pad side;

FIG. 10 is a sectional view taken on the line 10-10 of FIG.

FIG. 11 is a sectional view taken on the line 11-11 of FIG. 10;

FIG. 12 is an elevational view ofa further modified form of earcup embodying the invention, looking from the sealing pad side;

FIG. 13 is a side elevational view of the earcup of FIG. 12, looking from the rear;

FIG. 14 is a top view ofthe earcup of FIG. 12;

FIG. 15 is an enlarged sectional view taken along the line 1515 ofFIG.12;

FIG. 16 is an enlarged sectional view taken along the line 1616 of FIG. 12;

FIG. 17 is an enlarged sectional view taken along the line 17-17 ofFlG. 12;

FIG. 18 is an enlarged sectional view taken along the line 18-18 ofFIG. 12;

FIG. 19 is a fragmentary elevational view ofa modified form of the earcup of FIGS. l218, looking from the sealing pad side; and

FIG. 20 is a sectional view taken along the line 20-20 of FIG. 19.

DETAILED DESCRIPTION FIGS. 13

The sound-attenuating earcup illustrated may be supported by means disclosed in US. Pat. No. 3,470,564 and is intended to be biased lightly against the head of the wearer. For example, the biasing means may be that disclosed in said copending application. It will be understood, of course, that this is simply one convenient way of biasing the earcup and is not to be taken as a limitation on the present invention.

The earcup comprises a rigid cup-shaped shell 20 which may be of plastic or other suitable material. The open end of the shell is provided with an inwardly extending flange 24. This flange can be an integral part of the shell or can be a separate element suitably attached to the rim of the shell 20, for example, by bonding. The principal function of the flange is to provide a broader base then the rim of shell 20 for supporting a resilient sealing pad 30.

The shell 20 is provided with an outwardly extending pair of spaced flanges 26, which extend peripherally around the shell 20. These flanges 26 define a channel for receiving a shield 14 on which the shell is supported.

The resilient sealing pad 30, which embodies the essential features of the present invention, is elliptically annular in shape, like the rim ofthe earcup 20, so as to encircle the ear of the wearer. The pad 30 is formed of a softly resilient, preferably moldable material, such as a sponge plastic. While many of the sponge rubbers are suitable, it is presently preferred to use a resilient sponge silicone. The term "sponge plastic" as used in this specification is intended to be a generic term inclusive of sponge rubbers and sponge silicones, as well as other sponge plastic materials.

As seen in cross section, the pad 30 comprises a base 30a adapted for attachment, as by bonding, to the flange 24 of the shell 20, and divergent inner and outer head-engaging flanges 30b and 30c. Each of the flanges 30b and 30c terminates in a smoothly curved surface, so that it may engage the head comfortably. The flanges 30b and 30: define a broad, smoothly curved channel 30d between them. The flanges 30b and 30c respectively extend beyond the inner and outer peripheral walls ofthe base 30a to which it is attached, as shown at 30e in FIG. 2, so that when the flanges 30b and 300 are pushed into engagement with the wearer's head, as shown in FIG. 3, the material at the bottom of the channel 30d is stretched, and thereby stressed in tension. This tension ofthe material at 30d pulls the flanges 30b and 300 more firmly into engagement with the wearer's head, and greatly improves the seal against external sounds, without increasing the wearer's discomfort. This effect may be achieved with a total biasing force acting against the earcup of the order of 6 to 8 ounces. This force is spread around both flanges and around the entire periphery of the earcup, so that the pressure felt by the wearer is extremely light.

The pad 30 is preferably provided with a flap 30f which overlies the outer edge of the flange 24 and the outer rim of the cup 20. This flap is particularly desirable when the flange 24 is formed separately from the cup 20, as shown, so as to guard against possible sound leakage paths through the connection between cup 20 and flange 24.

In order to conform to the head of a wearer, the head-engaging surface of the pad 30 is contoured as shown in FIGS. 1 and 2. The tip of the inner flange 30b lies in a single plane, but the outer flange 30c follows the average humps and hollows of a human head along a path encircling the ear. Starting from the top and proceeding toward the front, the thickness of the flange, measured from the rim of the earcup to the flange tip, at first increases sharply and then decreases gradually in a downward direction along the front of the ear, reaching a minimum at the bottom. Proceeding upwardly along the flange behind the ear, the flange thickness increases gradually until it reaches a maximum thickness about two-thirds of the way to the top, and then decreases more rapidly to another minimum at the top.

At each point around the periphery of the earcup, the thickness of the inner flange 30b, measured from the flange 24 to the tip of flange 30b, is less than the corresponding thickness of the outer flange 300 at the same point. Furthermore, the thickness of flange 30b is substantially constant around the entire periphery. While this is the presently preferred construction, it is within the scope of the invention to make the inner flange 30b of varying thickness, or even to make it thicker than the outer flange, at least at some points.

In some cases, the inner flange 30b may be omitted.

The pad 30, constructed as described above, is not only more comfortable to the wearer of the earcup than previous pad structures, but is also more effective in attenuating external sounds.

FIG.4

This figure illustrates a modified pad 32, which may be used in place of the pad 30. While the pad 30 of FIGS. 1-3 is shown as being formed of the same material throughout, the pad 32 has an internal space 32a filled with a core or insert 34 ofa different material, e.g. foam rubber.

FIG. 5

Here, the internal space 32a is filled with air instead of foam rubber.

FIG. 6

FIG. 7

Under some conditions of use (e.g., widely varying ambient pressures), of the earcup as described in the preceding figures, it may be found that the earcup is too tightly sealed, so that it may be difficult to disengage it from the head. ln such circumstances, it may be desirable to incorporate a pressure equalizer device in the earcup.

As shown in FIG. 7, the shell is provided with an aperture at a convenient location, in which a grommet 40 of suitable material, e.g. rubber, is inserted. The grommet 40 is itself provided with a central aperture 40a on the periphery of which are formed helical ridges 40b. A spool 42 having similar helical ridges 42a is inserted in the aperture 400. There is thus formed between the spool 42 and the grommet 40 a tortuous passage, through which air may slowly leak in either direction, in order to equalize pressure differences. Nevertheless, sound waves cannot move through the passage without substantial attenuation.

FlG.8

This figure illustrates a modified form of pressure-equalizing device including a grommet 50 and a spool 52, corresponding generally to grommet 40 and spool 42 of FIG. 7. In this figure, the helical ridges on the grommet and spool are much higher than in FIG. 7.

In either of FIGS. 7 and 8, the spool may be assembled in the grommet simply by threading it in, and the parts may be held together by any suitable means, e.g. bonding.

FIGS. 911

These figures illustrate an earcup 20, which may be structurally the same as the earcup 20 of FIGS. 1 to 8, on which is mounted a modified form of sealing pad generally indicated by the reference numeral 60. The pad 60 includes a base surface 60a adapted for attachment, as by bonding, to the flange 24 of the shell 20 and diverging inner and outer head-engaging flanges 60b and 600. Except as specifically mentioned hereinafter, the pad 60 is structurally the same as the pad 30 of FlGS. l to 8.

The outer flange 60c of the pad 60 is contoured somewhat differently than the outer flange 30c of the sealing pad 30. Starting at the top of the outer flange and proceeding toward the front, i.e. toward the left in FIG. 9, the thickness of the flange 60c, measured from the rim of the earcup to the flange tip, increases gradually, reaching a maximum about two-thirds of the way down the front-side of the pad. From there, the flange thickness is substantially constant to the bottom of the pad. Just to the rear of the bottom, there is a pronounced valley 60d in the profile of the pad, as seen in FIG. 10. The valley 60d is intended to accommodate a part of the human head which protrudesjust below and behind'the ear. From the valley 60d, the thickness of the flange 60c increases gradually in an upward direction, reaching a maximum about twothirds of the way to the top of the pad and then decreasing gradually again until the top is reached.

The pad 600 is provided with a flap 60e, corresponding to the flap 30fof FIGS. 1 to 8. Flap 60e engages the outer surface of the cup 20 and holds the pad 60 in place on the cup. Within the flap 60e, preferably at its innermost cup-engaging surface, there is molded a coil spring 61. The unstressed length of coil spring 61 is smaller than the periphery of the earcup, so that the spring 61 is effective to hold the pad 60 firmly in position on the earcup. Note that the spring 61 engages the earcup inbe used in place of one or more portions of the coil spring, with the ends of such embedded wire or wires connected by coil Springs.

FIGS. l2-18 These figures illustrate a modification of the invention again including an earcup shell 20, substantially identical in structure to the shell 20 described above, but shown as having only a single outwardly projecting peripheral flange 26 for attachment to supporting structure. Thus the shell 20 has an inwardly extending flange 24 constituting the shell rim, having an elliptically annular planar surface and defining a generally elliptical opening. On this shell, there is mounted a softly resilient sealing pad 63 having an elliptically annular base 63a, one side of which is secured to the shell rim (flange 24) in engagement with the plane surface of flange 24. The pad further includes an elliptically annular sealing portion 63b formed integrally with base 63a and projecting therefrom in a direction away from the shell rim, for engagement with the head of a wearer in encircling relation to the wearer's car.

As shown in the sectional views (FIGS. l5l8), the pad 63 may comprise an elliptically annular body 65 of a softly resilient material such as a sponge plastic, e.g. of the type employed in the pads shown in FIGS. lll and described above. By way of further illustration, a so-called self-foaming" material (for example, a self-foaming polyurethane composition) may be used to form the body 65, being poured into an appropriately shaped mold and caused to expand by selffoaming action to fill the mold cavity; such materials, and the molding procedure used to form articles from them, are well known and accordingly need not be described in detail. The body is encased in a flexible layer 66 of plastic material or the like, having a flap 660 that projects outwardly from the pad (i.e. away from the wearer's head) over the outer surface of the cup 20 and over the lip 24a of flange 24, to aid in holding the pad in place on the shellv The sealing portion 63b of the pad has a sealing surface 68 which faces away from the cup 20, in position for contact with the wearers head. The outer and inner peripheries of this sur face, respectively designated 70 and 71, are elliptically annular in configuration, disposed in surrounding relation to the earcup opening, and spaced apart substantially equidistantly from each other at all points around the periphery ofthe opening, i.e. as viewed in FIG. 12. In the form shown, the outer sidewall of the pad sealing portion 63b diverges radially outward (with respect to the axis of the shell 20) from the base 630 to the sealing surface outer periphery 70, while the inner sidewall of portion 63b projects in the direction of the shell axis from the base 630 to the sealing surface inner periphery 71; hence the sealing surface defined between

peripheries

70 and 71 is somewhat greater in width than the base.

In accordance with the invention, the outer thickness of the pad sealing portion 63b (i.e. the dimension of portion 63b between the base 63a and the sealing surface outer periphery 70) varies smoothly and continuously around the periphery between successive maxima and minima. FIGS. 12l8 illustrate a specific embodiment of this dimensional variation, in an earcup for enclosing a wearer's right ear; decreases corresponding left earcup would be a mirror just of that shown. Starting at the top of the earcup and proceeding initially downwardly toward the front, in FIGS. l2l8, the sealing portion outer thickness increases rapidly to a first maximum 70a about one-third of the way to the bottom of the shell, then decreases gradually to a minimum 70b just forwardly of the bottom of the shell, then increases upwardly toward the back to a maximum 70c in the rear about a third of the way to the top of the shell, and decreases gradually to a further minimum 70d just rearwardly of the top of the shell.

The inner thickness of the sealing portion 63b (i.e. the dimension of portion 63b between the base 63a and the sealing surface inner periphery 71) is shown in FIGS. 12-18 as substantially constant at all points around the periphery of the earcup opening and about equal to the minimum value of the aforementioned outer thickness. In practice, it may be desirable to provide some moderate degree of variation in the inner thickness ofthe pad portion 63b, following generally the variation in outer thickness; but in any event, the inner thickness is such that at each minimum point (70b, 70d) of the outer thickness the sealing surface outer periphery 70 is spaced at least as far from the base 630 as is the nearest adjacent point on the sealing surface inner periphery 71, and every other point on the outer periphery 70 is spaced farther from the base 6311 than is the inner periphery 71.

Unlike the sealing surfaces of the pads of FIGS. lll, which are channel-shaped in cross-sectional profile, the surface 68 of pad 63 extends substantially rectilinearly from any given point on the outer periphery 70 to the nearest adjacent point on the inner periphery 71. Thus the pad 63 presents a single, wide annular head-engaging surface rather than (as in the embodiments of FIGS. lll) two spaced annular headengaging surface portions constituting the rounded crests of inner and outer flanges separated by a channel.

Owing to the above-described relative dimensions of the outer and inner thicknesses of the pad portion 63b (i.e. as measured at the outer and inner peripheries of the sealing surface, respectively) the sealing surface 68 slopes inwardly with respect to the axis of the shell, toward the earcup opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of the maxima (70a, 70c) and minima (70b, 70d) of the aforementioned outer thickness. In other words, the surface 68 slopes relatively steeply inward from the outer periphery from

points

70a and 700 corresponding to the outer thickness maxima (FIG. 18), and this slope flattens out as the distance between the outer periphery 70 and base 630 decreases, until at the localities of the outer thickness minima 70b and 70d, the surface 68 (as viewed in cross section, FIG. 16) may be substantially parallel to the plane of the rim flange 24. It will be understood that as herein used, the term pitch" refers to the angle between the lastmentioned plane and a line, tangent to the surface 68, projecting radially with respect to the earcup shell axis.

In use, when the earcup of FIGS. l2l8 is pressed against the wearer's head in surrounding relation to his ear, the surface 68 engages the head (at, and at least for a substantial distance inwardly of, the outer periphery 70 across the width of the surface) with continuous sound-attenuating sealing contact over a region completely encircling the ear. The described variations in outer thickness and surface slope of the pad portion 63b follow generally the hump-and-hollow contours of the average human head, so that the desired complete sealing contact can be achieved with advantageously light inward pressure. Such pressure effects moderate outward deformation of the outer peripheral edge portion of the pad (i.e. adjacent the outer surface periphery 70), as a result of the described outwardly diverging configuration of the pad outer wall, to enhance the sealing effect.

FIGS. 19-20 The sealing surface 68 of pad 63, which is shown in FIGS. l218 as extending substantially rectilinearly from any given point on the outer periphery 70 to the nearest adjacent point on the inner periphery 71, may instead be corrugated as shown in FIGS. 19-20. The corrugations comprise plural parallel elliptically annular ribs 74 with smoothly curved contours defining plural parallel elliptically annular grooves 75 (also having smoothly curved contours) between them. At any given point around the periphery of the earcup, the crests of all the ribs 74 (across the full width of the sealing surface) are tangent to a common line 76 extending radially with respect to the axis of the earcup shell.

Except for the surface corrugations, the structure, configuration, and dimensions of the pad 63 in FIGS. 19-20, including the pitch and slope of the sealing surface, may be exactly as described above with reference to FIGS. l2l8. It will be understood that the terms pitch and slope of the sealing surface," as applied to the corrugated surface of FIGS. 19-20, refer to the pitch and slope of the common tangent to the crests of the ribs 74.

The corrugations may conveniently be formed integrally with the annular body 65, by molding. Use ofa self-foaming" material as mentioned above to produce the annular body is especially effective for forming these corrugations. The outer layer 66 is shaped to conform closely to the corrugations of the annular body, as illustrated in FIG. 20. In use, when the seal is pressed against the wearers head, the grooves 75 provide dead air spaces that contribute to the sound-attenuating effect of the seal.

In any ofthe earcup devices illustrated, an earphone may be incorporated so that the wearer may receive communications.

It is to be understood that the invention is not limited to the features and embodiments hereinabove specifically set forth, but may be carried out in other ways without departure from its spirit.

Iclaim:

1. An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearers ear, including a. a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and defining an elliptically annular opening into the shell interior, dimensioned to surround the wearer's ear;

wherein the improvement comprises:

b. a softly resilient sound-attenuating pad adapted for engagement with the head of a wearer along an area encircling the wearer's ear, comprising:

i. an elliptically annular base having one side secured to said shell rim and engaging said plane surface, and

ii. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer's head with elliptically annular outer and inner peripheries surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies around the periphery of the earcup, said dimension increasing toward the front from the top to a first maximum in the front portion of said sealing surface outer periphery, then decreasing gradually to a minimum adjacent the bottom, then increasing upwardly toward the back to a maximum in the rear portion of said sealing surface outer periphery and then decreasing gradually to another minimum adjacent the top.

2. An earcup as defined in claim I, wherein said sealing surface includes an elliptically annular channel disposed between said outer periphery and said inner periphery thereof, and said sealing portion comprises outer and inner flanges respectively projecting radially outward and radially inward with respect to the axis of said shell, and said outer and inner peripheries of said sealing surface respectively comprising head-engaging surfaces ofsaid outer and inner flanges.

3. An earcup as defined in claim 1, wherein said sealing surface extends substantially rectilinearly from any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof.

4. An earcup as defined in claim 3, wherein said sealing surface slopes inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery,

5. An earcup as defined in claim 1, wherein said sealing portion has a dimension between the rim-engaging base and said sealing surface inner periphery such that at each said minimum sealing portion dimension between said rimengaging base and said sealing surface outer periphery, said sealing surface outer periphery is spaced at least as far from the rimengaging base as is the nearest adjacent point on said sealing surface inner periphery, and every other point on said outer periphery is spaced farther from the rim-engaging base than is said sealing surface inner periphery.

6. An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearer's ear, including a. a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and defining an elliptically annular opening into the shell interior, dimensioned to surround the wearers ear;

wherein the improvement comprises:

b. a softly resilient sound-attenuating pad adapted for engagement with the head of a wearer along an area encircling the wearers ear, comprising:

ii. outer and inner elliptically annular flanges projecting from the base in a direction away from said one side, said flanges surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said outer and inner flanges respectively projecting in a radially outward direction and in a radially inward direction with respect to the axis of said shell, so that said flanges are deflected from their respective unstressed positions when in engagement with the wearer's head, said flanges defining between them a channel which is stressed in tension by said deflection of said flanges so as to hold the flanges firmly but lightly against the wearers head, said. flanges having smooth rounded contours, the surface of said channel extending in a smooth continuous curve from said outer flange to said inner flange, and said outer flange has a head-engaging surface and a dimension between the rim-engaging base and said head-engaging surface which varies around the periphery of the earcup, said dimension increasing rapidly toward the front from a first minimum at the top to a first maximum in the front portion of said outer flange, then decreasing gradually to a minimum at the bottom, then increasing gradually upwardly toward the back to a maximum about two-thirds of the way to the top and then decreasing gradually to another minimum at the top.

7. An earcup as defined in claim 6, wherein said inner flange has a head-engaging surface and a dimension between the rimengaging base and said head-engaging surface of said inner flange which is substantially constant around the periphery of said opening and is less than the corresponding dimension of 'said outer flange at every point around the periphery of said earcup.

8. An earcup as defined in claim 6, wherein the improve ment further comprises means for equalizing the pressure inside the earcup with the external pressure, said pressureequalizing means including a grommet of resilient material inserted in an aperture in said shell, said grommet having a helically threaded hole extending therethrough from the inside to the outside of the shell, and a helically threaded spool within said hole, the helical threads onthe spool loosely fitting the threads on the grommet so as to provide a tortuous open passage of small cross section for flow of air between the inside and outside of said shell, said passage being effective to equalize pressure inside and outside the shell and to attenuate sound waves passing therethrough from the outside to the inside of the shell.

9. An earcup as defined in claim 6, wherein said base is hollow, defining an elliptically annular chamber.

10. An earcup as defined in claim 6, wherein said channel includes a third elliptically annular flange with smoothly rounded contours intermediate said outer and inner flanges and projecting from said channel in a direction away from said rim-engaging side of said base 1]. An earcup as defined in claim 6, wherein said shell rim comprises an elliptically annular discrete rigid rim member mounted on the edge of said shell, and wherein said pad further includes an annular flap projecting from said base in a direction away from said outer and inner flanges and overlying the junction between said rim memberand said shell.

12. An earcup as defined in claim 11, wherein said rim member includes an annular lip projecting outwardly from the edge of said shell, and further including an annular resilient member including a helical spring carried by said flap and adapted to surround and grip the outer surface of said shell on the side of said lip away from the wearers head to retain said pad in position on said shell rim.

13. A softly resiliently sound-attenuating pad adapted to be secured to an elliptically annular rim ofa rigid earcup shell for engagement with the head of a wearer along an area encircling the wearers ear, wherein said rim defines an opening dimen sioned to surround the wearers ear, said pad comprising:

a. an elliptically annular base having one side adapted to be secured to said shell rim in engagement with an elliptically annular plane surface thereof; and

b. outer and inner elliptically annular flanges projecting from the base in a direction away from said one side, said flanges surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said outer and inner flanges respectively projecting in a radially outward direction and in a radially inward direction with respect to the axis of said shell, so that said flanges are deflected from their respective unstressed positions when in engagement with the wearers head, said flanges defining between them a channel which is stressed in tension by said deflection of said flanges so as to hold the flanges firmly but lightly against the wearers head, said flanges having smooth rounded contours, the surface of said channel extending in a smooth continuous curve from said outer flange to said inner flange, said outer flange having a head-engaging surface and a dimension between the rim-engaging base and said head-engaging surface which varies around the periphery of the earcup, said dimension increasing rapidly toward the front from a first minimum at the top to a first maximum in the front portion of said outer flange, then decreasing gradually to a minimum at the bottom, then increasing gradually upwardly toward the back to a maximum about two-thirds of the way to the top and then decreasing gradually to another minimum at the top.

14. An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearer's ear, including a a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and defining an elliptically annular opening into the shell interior, dimensioned to surround the wearer's ear;

wherein the improvement comprises:

b. a softly resilient sound-attenuating pad adapted for engagement with the head of a wearer along an area encircling the wearer's ear, comprising i. an elliptically annular base having one side secured to said shell rim and engaging said plane surface, and

ii. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer's head with elliptically annular outer and inner peripheries surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said sealing surface being adaptcd to engage the wearers head substantially continuously at all points between said outer and inner peripheries and extending substantially rectilinearly between any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies around the periphery of the earcup, said dimension increasing toward the front from the top to a first maximum in the front portion of said sealing surface outer periphery about one-third of the way to the bottom, then decreasing gradually to a minimum just forwardly of the bottom, then increasing upwardly toward the back to a maximum about one-third of the way to the top and then decreasing gradually to another minimum just rearwardly of the top, said sealing portion further having a dimension between the rim-engaging base and said sealing surface inner periphery such that at each said minimum sealing portion dimension between said rim-engaging base and said sealing surface outer periphery, said sealing surface outer periphery is spaced at least as far from the rim-engaging base as is the nearest adjacent point on said sealing surface inner periphery, and every other point on said outer periphery is spaced farther from the rim-engaging base than is said sealing surface inner periphery.

157 An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearer's ear, including a. a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and dcfining an elliptically annular opening into the shell in terior, dimensioned to surround the wearer's ear;

wherein the improvement comprises;

ii. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer's head with elliptically annular outer and inner peripheries surrounding said opening and spaced apart, said surface extending substantially rectilinearly between any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies smoothly and continuously around the periphery of the earcup between maxima and minima, and said sealing surface sloping inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery.

16. A softly resilient sound-attenuating pad adapted to be secured to an elliptically annular rim ofa rigid earcup shell for engagement with the head ofa wearer along an area encircling the wearers ear, wherein said shell defines an elliptically annular opening dimensioned to surround the wearer's ear, said pad comprising:

b. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer's head with elliptically annular outer and inner peripheries surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said sealing portion having a dimension between the rim-engaging base and said seal ing surface outer periphery which varies around the periphery of the earcup, said dimension increasing toward the front from the top to a first maximum in the front portion of said sealing surface outer periphery, then decreasing gradually to a minimum adjacent the bottom, then increasing upwardly toward the back to a maximum in the rear portion of said sealing surface outer periphery and then decreasing gradually to another minimum adjacent the top.

17, A pad as defined in claim 16, wherein said sealing sur face extends substantially rectilinearly from any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, and slopes inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-cngaging base and said sealing surface outer periphery.

18. A pad as defined in claim 17, wherein said first maximum of said sealing portion dimension is positioned about one-third ofthe way to the bottom of the shell, said minimum adjacent the bottom is positioned just forwardly ofthe bottom of the shell, said maximum in the rear portion of said sealing surface outer periphery is positioned about one-third of the way to the top of the shell, and said minimum adjacent the top is positioned just rearwardly ol'the top.

19. A softly resilient sound-attenuating pad adapted to be secured to an elliptically annular rim ofa rigid earcup shell for engagement with the head of the wearer along an area encircling the wearer's ear, wherein said rim defines an opening dimensioned to surround the wearers ear, said pad comprising:

a. an elliptically annular base having one side adapted to be secured to'said shell rim in engagement with an elliptically annular plane surface thereof; and

b. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer's head with elliptically annular outer and inner peripheries surrounding said opening and spaced apart, said surface extending substantially rectilinearly between any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies smoothly and continuously around the periphery of the earcup between maxima and minima, and said sealing surface sloping inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery.

20. An earcup as defined in claim 1, wherein said sealing surface is corrugated and slopes inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery.

21. An earcup as defined in claim 20, wherein the corrugated sealing surface comprises plural parallel elliptically annular ribs defining plural parallel elliptically annular grooves between them.

Claims

1. An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearer''s ear, including a. a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and defining an elliptically annular opening into the shell interior, dimensioned to surround the wearer''s ear; wherein the improvement comprisEs: b. a softly resilient sound-attenuating pad adapted for engagement with the head of a wearer along an area encircling the wearer''s ear, comprising: i. an elliptically annular base having one side secured to said shell rim and engaging said plane surface, and ii. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer''s head with elliptically annular outer and inner peripheries surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies around the periphery of the earcup, said dimension increasing toward the front from the top to a first maximum in the front portion of said sealing surface outer periphery, then decreasing gradually to a minimum adjacent the bottom, then increasing upwardly toward the back to a maximum in the rear portion of said sealing surface outer periphery and then decreasing gradually to another minimum adjacent the top.

2. An earcup as defined in claim 1, wherein said sealing surface includes an elliptically annular channel disposed between said outer periphery and said inner periphery thereof, and said sealing portion comprises outer and inner flanges respectively projecting radially outward and radially inward with respect to the axis of said shell, and said outer and inner peripheries of said sealing surface respectively comprising head-engaging surfaces of said outer and inner flanges.

4. An earcup as defined in claim 3, wherein said sealing surface slopes inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery.

5. An earcup as defined in claim 1, wherein said sealing portion has a dimension between the rim-engaging base and said sealing surface inner periphery such that at each said minimum sealing portion dimension between said rim-engaging base and said sealing surface outer periphery, said sealing surface outer periphery is spaced at least as far from the rim-engaging base as is the nearest adjacent point on said sealing surface inner periphery, and every other point on said outer periphery is spaced farther from the rim-engaging base than is said sealing surface inner periphery.

6. An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearer''s ear, including a. a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and defining an elliptically annular opening into the shell interior, dimensioned to surround the wearer''s ear; wherein the improvement comprises: b. a softly resilient sound-attenuating pad adapted for engagement with the head of a wearer along an area encircling the wearer''s ear, comprising: i. an elliptically annular base having one side secured to said shell rim and engaging said plane surface, and ii. outer and inner elliptically annular flanges projecting from the base in a direction away from said one side, said flanges surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said outer and inner flanges respectively projecting in a radially outward direction and in a radially inward direction with respect to the axis of said shell, so that said flanges are deflected from thEir respective unstressed positions when in engagement with the wearer''s head, said flanges defining between them a channel which is stressed in tension by said deflection of said flanges so as to hold the flanges firmly but lightly against the wearer''s head, said flanges having smooth rounded contours, the surface of said channel extending in a smooth continuous curve from said outer flange to said inner flange, and said outer flange has a head-engaging surface and a dimension between the rim-engaging base and said head-engaging surface which varies around the periphery of the earcup, said dimension increasing rapidly toward the front from a first minimum at the top to a first maximum in the front portion of said outer flange, then decreasing gradually to a minimum at the bottom, then increasing gradually upwardly toward the back to a maximum about two-thirds of the way to the top and then decreasing gradually to another minimum at the top.

7. An earcup as defined in claim 6, wherein said inner flange has a head-engaging surface and a dimension between the rim-engaging base and said head-engaging surface of said inner flange which is substantially constant around the periphery of said opening and is less than the corresponding dimension of said outer flange at every point around the periphery of said earcup.

8. An earcup as defined in claim 6, wherein the improvement further comprises means for equalizing the pressure inside the earcup with the external pressure, said pressure-equalizing means including a grommet of resilient material inserted in an aperture in said shell, said grommet having a helically threaded hole extending therethrough from the inside to the outside of the shell, and a helically threaded spool within said hole, the helical threads on the spool loosely fitting the threads on the grommet so as to provide a tortuous open passage of small cross section for flow of air between the inside and outside of said shell, said passage being effective to equalize pressure inside and outside the shell and to attenuate sound waves passing therethrough from the outside to the inside of the shell.

10. An earcup as defined in claim 6, wherein said channel includes a third elliptically annular flange with smoothly rounded contours intermediate said outer and inner flanges and projecting from said channel in a direction away from said rim-engaging side of said base.

11. An earcup as defined in claim 6, wherein said shell rim comprises an elliptically annular discrete rigid rim member mounted on the edge of said shell, and wherein said pad further includes an annular flap projecting from said base in a direction away from said outer and inner flanges and overlying the junction between said rim member and said shell.

12. An earcup as defined in claim 11, wherein said rim member includes an annular lip projecting outwardly from the edge of said shell, and further including an annular resilient member including a helical spring carried by said flap and adapted to surround and grip the outer surface of said shell on the side of said lip away from the wearer''s head to retain said pad in position on said shell rim.

13. A softly resiliently sound-attenuating pad adapted to be secured to an elliptically annular rim of a rigid earcup shell for engagement with the head of a wearer along an area encircling the wearer''s ear, wherein said rim defines an opening dimensioned to surround the wearer''s ear, said pad comprising: a. an elliptically annular base having one side adapted to be secured to said shell rim in engagement with an elliptically annular plane surface thereof; and b. outer and inner elliptically annular flanges projecting from the base in a direction away from said one side, said flanges surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said Outer and inner flanges respectively projecting in a radially outward direction and in a radially inward direction with respect to the axis of said shell, so that said flanges are deflected from their respective unstressed positions when in engagement with the wearer''s head, said flanges defining between them a channel which is stressed in tension by said deflection of said flanges so as to hold the flanges firmly but lightly against the wearer''s head, said flanges having smooth rounded contours, the surface of said channel extending in a smooth continuous curve from said outer flange to said inner flange, said outer flange having a head-engaging surface and a dimension between the rim-engaging base and said head-engaging surface which varies around the periphery of the earcup, said dimension increasing rapidly toward the front from a first minimum at the top to a first maximum in the front portion of said outer flange, then decreasing gradually to a minimum at the bottom, then increasing gradually upwardly toward the back to a maximum about two-thirds of the way to the top and then decreasing gradually to another minimum at the top.

14. An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearer''s ear, including a. a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and defining an elliptically annular opening into the shell interior, dimensioned to surround the wearer''s ear; wherein the improvement comprises: b. a softly resilient sound-attenuating pad adapted for engagement with the head of a wearer along an area encircling the wearer''s ear, comprising i. an elliptically annular base having one side secured to said shell rim and engaging said plane surface, and ii. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer''s head with elliptically annular outer and inner peripheries surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said sealing surface being adapted to engage the wearer''s head substantially continuously at all points between said outer and inner peripheries and extending substantially rectilinearly between any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies around the periphery of the earcup, said dimension increasing toward the front from the top to a first maximum in the front portion of said sealing surface outer periphery about one-third of the way to the bottom, then decreasing gradually to a minimum just forwardly of the bottom, then increasing upwardly toward the back to a maximum about one-third of the way to the top and then decreasing gradually to another minimum just rearwardly of the top, said sealing portion further having a dimension between the rim-engaging base and said sealing surface inner periphery such that at each said minimum sealing portion dimension between said rim-engaging base and said sealing surface outer periphery, said sealing surface outer periphery is spaced at least as far from the rim-engaging base as is the nearest adjacent point on said sealing surface inner periphery, and every other point on said outer periphery is spaced farther from the rim-engaging base than is said sealing surface inner periphery.

15. An earcup adapted to be pressed against the head of a wearer in surrounding relation to the wearer''s ear, including a. a rigid cup-shaped shell with a rim having an elliptically annular plane surface facing away from said shell and defining an elliptically annular opening into the shell interior, dimensioned to surround the wearer''s ear; wherein the improvement comprises: b. a softly resiliEnt sound-attenuating pad adapted for engagement with the head of a wearer along an area encircling the wearer''s ear, comprising: i. an elliptically annular base having one side secured to said shell rim and engaging said plane surface, and ii. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer''s head with elliptically annular outer and inner peripheries surrounding said opening and spaced apart, said surface extending substantially rectilinearly between any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies smoothly and continuously around the periphery of the earcup between maxima and minima, and said sealing surface sloping inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery.

16. A softly resilient sound-attenuating pad adapted to be secured to an elliptically annular rim of a rigid earcup shell for engagement with the head of a wearer along an area encircling the wearer''s ear, wherein said shell defines an elliptically annular opening dimensioned to surround the wearer''s ear, said pad comprising: a. an elliptically annular base having one side adapted to be secured to said shell rim in engagement with an elliptically annular plane surface thereof; and b. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer''s head with elliptically annular outer and inner peripheries surrounding said opening and being spaced apart substantially equidistantly from each other at all points around the periphery of said opening, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies around the periphery of the earcup, said dimension increasing toward the front from the top to a first maximum in the front portion of said sealing surface outer periphery, then decreasing gradually to a minimum adjacent the bottom, then increasing upwardly toward the back to a maximum in the rear portion of said sealing surface outer periphery and then decreasing gradually to another minimum adjacent the top.

17. A pad as defined in claim 16, wherein said sealing surface extends substantially rectilinearly from any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, and slopes inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery.

18. A pad as defined in claim 17, wherein said first maximum of said sealing portion dimension is positioned about one-third of the way to the bottom of the shell, said minimum adjacent the bottom is positioned just forwardly of the bottom of the shell, said maximum in the rear portion of said sealing surface outer periphery is positioned about one-third of the way to the top of the shell, and said minimum adjacent the top is positioned just rearwardly of the top.

19. A softly resilient sound-attenuating pad adapted to be secured to an elliptically annular rim of a rigid earcup shell for engagement with the head of the wearer along an area encircling the wearer''s ear, wherein said rim defines an opening dimensioned to surround the wearer''S ear, said pad comprising: a. an elliptically annular base having one side adapted to be secured to said shell rim in engagement with an elliptically annular plane surface thereof; and b. an elliptically annular sealing portion projecting from the base in a direction away from said one side, and having a sealing surface for engaging the wearer''s head with elliptically annular outer and inner peripheries surrounding said opening and spaced apart, said surface extending substantially rectilinearly between any given point on said outer periphery thereof to the nearest adjacent point on said inner periphery thereof, said sealing portion having a dimension between the rim-engaging base and said sealing surface outer periphery which varies smoothly and continuously around the periphery of the earcup between maxima and minima, and said sealing surface sloping inwardly with respect to the axis of said shell, toward said opening, with a pitch that varies smoothly and continuously around the periphery of the earcup between maxima and minima respectively positioned at the localities of said maxima and minima of the sealing portion dimension between the rim-engaging base and said sealing surface outer periphery.