US3719954A

US3719954A - Head set construction

Info

Publication number: US3719954A
Application number: US00010787A
Authority: US
Inventors: F Beguin
Original assignee: American Optical Corp
Current assignee: Aearo Technologies LLC
Priority date: 1970-02-12
Filing date: 1970-02-12
Publication date: 1973-03-13
Anticipated expiration: 1990-03-13
Also published as: CA926787A; FR2078583A5; JPS5327597B1; GB1340923A; DE2105292A1

Abstract

Headset construction including headband and earcups having connecting means therebetween allowing smooth dampened swivelling action of earcups into desired close-fitting positions against wearer''s head and about his ears and with said connecting means arranged to allow headband to be readily adjusted to different lengths and pivoted relative to earcups so as to be worn in any one of several different positions as conditions of use require.

Description

United States Patent [191 Beguin 1March 13, 1973 [73] Assignee: American Optical Corporation, Southbridge, Mass.

22 Filed: Feb. 12,1970 21 Appl.N0.: l0,787

[52] US. Cl ..2/209 [51] Int. Cl. ..A41d 21/00 [58] Field of Search ..2/209, 3, 6, 8, 174; 179/182 R, 156; 248/256 [56] References Cited UNITED STATES PATENTS 2,858,544 11/1958 Roth ..2/209 2,506,981 4/1970 Stewart et a1 ..2/209 2,505,684 4/1970 Hutchinson et a1. ..2/209 3,108,282 10/1963 Rehman et al ..2/209 X 3,461,463 8/1969 Beguin ..2/209 X 2,437,748 3/1948 Malcom ..2/8

FOREIGN PATENTS OR APPLICATIONS 1,145,964 5/1957 France ..2/209 Primary ExaminerGeorge H. Krizmanieh Attorney-William C. Nealon, Noble S. Williams and Robert J. Bird [57] ABSTRACT Headset construction including headband and earcups having connecting means therebetween allowing smooth dampened swivelling action of earcups into desired close-fitting positions against wearer's head and about his ears and with said connecting means arranged to allow headband to be readily adjusted to different lengths and pivoted relative to earcups so as to be worn in any one of several different positions as conditions of use require,

2 Claims, 7 Drawing Figures PATH-HEUMAR 1 31973 sum 2 or 2 INVENTOR. FRED P BEGUIN FIG? I AT ORNEY HEAD SET CONSTRUCTION This invention relates to improvements in headset constructions for ambient sound attenuation, and more particularly to a headset construction comprising a headband and a pair of earcups having improved connecting means therebetween for allowing each earcup to be smoothly universally swivelled into any desired position of use against the wearers head and in closefitting relation about the wearers ears while also allowing the headband to be adjusted in length, as required, and moved into and retained in any one of several different operative positions during use of the headset.

More particularly, the headset comprises a flexible headband and a pair of earcups which are swivelly carried upon opposite end portions of the flexible headband by improved connecting means which is of such construction and arrangement as to provide smooth firm frictional sliding resistance to the movable parts of the structure as well as allow the wearer of the headset to easily and readily adjust each earcup into its proper position surrounding the wearers ear and bearing in close-fitting condition against the wearers head. At the same time, the connecting means construction and arrangement is such that the flexible headband may be readily adjusted as needed without requiring the tightening or loosening of parts, to position the headband over the head, or under the chin, or even in back of the head near the wearers neck as desired. Furthermore, the built-in frictional resistance of the adjustable parts of the structure is such that it will thereafter tend to retain the headband in such adjusted position unless forcefully disturbed or purposely manipulated; and this built-in frictional resistance will remain substantially constant even though the parts are pivoted many hundreds of times during the use thereof.

The improved connecting means mentioned above between each earcup and an end portion of the headband and providing the so-called built-in frictional resistance includes ball-and-socket means which has been so carefully controlled during the production thereof as to size of parts and physical characteristics of materials employed that not only will smooth sliding action of the parts be had over long periods of use but also it will be such that the amount of frictional resistance desired will be provided and will be maintained substantially constant. Thus, the smooth firm dampened sliding condition between the parts will always be present and this frictional resistance can always be depended upon to hold the parts in their adjusted posi tion during use of the device. Also, the controlled character and arrangement of the parts and the smooth firm frictional resistance provided is such that the headband may be easily adjusted lengthwise for different conditions requiring different distances between the earcups carried near the opposite ends thereof. Additionally, the improved construction comprises adjustable slidable connecting means which is such that said headset may be readily adapted to fit any one of a wide range of different size requirements for different conditions of use.

It is, accordingly, an object of the present invention to provide an improved headset comprising a flexible headband and a pair of earcups carried near the opposite ends of said headband by connecting means which is of such improved construction and arrangement that each earcup may be universally swivelled suitable amounts in any direction with reference to said headband in order to allow the earcup to fit about the wearers ears and evenly and snugly against the wearers head, and which earcups may each be rotated as desired about its central axis for fitting purposes. Also, the connecting means allows the headband to be pivoted as desired into any one of its several normal operative positions above, in front of or to the rear of the wearers head and firmly frictionally retained in any such operative position during use thereof. It is also an object of the present invention to provide a method for making ball-and-socket connections of the character described and which are such as may be used between the headband and earcups of a sound-attenuating headset, a stereo headset, a communication headset or the like, the connections allowing limited universal swivelling smoothly damped movement of the earcups of the like relative to its supporting structure, such as the headband while providing proper amounts of friction resistance between the operative parts thereof such that not only can the desired adjustments of the earcups to a wearers head be easily and smoothly made but also, at the same time, sufficient amounts of resistance to change of position are provided. Thus, the headband and earcups will normally be retained in their adjusted positions during normal use of the equipment and, on the other hand, the earcups may be readily forcefully pressed, without the loosening or tightening of any parts, into any other position of adjustment desired.

Other objects and advantages of the invention will be apparent from the detailed description which follows when taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of a headset embodying the present invention;

FIG. 2 is an enlarged fragmentary view of a part of the structure of FIG. 1;

FIG. 3 is a transverse sectional view taken substantially upon section line 3-3 of FIG. 2 and looking in the direction of the arrows;

FIG. 4 is an exploded view of the parts of the structure of FIG. 3;

FIG. 5 is a fragmentary side elevational view showing a modified form of the invention; 7

FIG. 6 is a vertical sectional view taken substantially along section line 6-6 of FIG. 5; and

FIG. 7 is a vertical sectional view showing complementary mold parts for use in carrying out method steps of the present invention.

Referring to the drawings in detail and in particular FIG. 1, there is indicated at 10 a headset comprising a resilient or spring-type headband l2 and a pair of earcups 14 carried thereby. The connecting means for this purpose will be later described. Preferably, the headband would be formed of flat spring steel, stiff plastic, fiber glass or the like of such characteristics as to afford the firm but yieldable pressure desired between the earcups and the opposite sides of the wearer's head while in use.

Each earcup is of a hollow one-piece construction and formed of a moldable plastic material. As shown, the earcup comprises an outer generally circular wall portion 14a peripherally connected to an endless side portion 14b of frusto-conical shape. The molded earcup is open at its inner side but may be provided with a small endless flange at its inner edge arranged to receive andhelp retain the outer thin flange of a flexible head-engaging resilient ear pad or cushion 16 in overlapping engagement with this peripheral flange. The cushion is provided centrally therein with an elongated opening 18 of suitable size and shape for receiving the ear of the wearer therein. A pair of front and rear flattened portions 20 are formed upon the outer surface of the wall portion 14b of each earcup in order to enable the wearer to easily feel and determine thereby the position of the earcup opening 18 without having to remove the headset.

Carried in the outer wall portion 14a of each earcup is a ball-headed stud 22 formed of metal, (see also FIGS. 2 and 3) which has its polished sphericallyshaped head portion 22a embedded within he plastic of the earcup during the molding thereof. In this way, the head portion 22a is permanently contained within and firmly gripped by the plastic forming a socket 25 in the molded plastic materialof the outer wall portion 14b at an enlarged thickened central region 24 thereof. The molded plastic-material about the stem portion 22b of the stud 22 is recessed at 27 in such a manner that limited universal pivotal movement of the stud about the geometric center of the ball-headed part 22a and relative to the earcup may be accomplished. The allowable pivotal movement of the stud in any direction from its centered position would be, in most cases, an angular amount approximating 15 to 20.

The stem portion 22b of the ball-headed stud 22, as shown in FIG. 3, is arranged to extend outwardly through an elongated slot 38 formed in an end portion 12a of the headband 12 and through a pair of

friction washers

30 and 32, preferably formed of a plastic, like nylon or teflon, disposed at opposite sides of the slotted end portion 12a. (Note that the construction and arrangement of parts for supporting the earcups of a headset are identical.) The outer end 22a of the stud of FIG. 3 is threaded to receive an adjustable stop-nut 34 and a spring washer is located between this nut and outer friction washer 32. This nut 34 can be easily adjusted to exert the amount of clamping action needed between the

friction washers

30, 32 and the slotted end portion to prevent unwanted longitudinal sliding action therebetween.

In order to prevent rotation between inner washer 30 and stud 22, a small pin 42 is provided (see FIG. 4) and arranged to extend through a bore 44 in the stud in such a way as to have engagement with a groove 46 provided in an upstanding collar portion 48 of inner washer 30. At the same time, in order to prevent rotation between the headband end portion 12a and

friction washers

30 and 32, an integral rectangular projecting rib 30a is formed on the inner side of washer 30 and is arranged to project outwardly sufficiently to extend through the slot 38 in headband l2 and into an elongated rectangular groove 32a formed in the inner wall of washer 32. Thus, it will be appreciated that the construction and arrangement of parts are such that no relative rotation between the

washers

30 and 32 or between these washers and the slotted end portions of the headband can occur. On the other hand, when the adjustment of the nut 34 against the outer side of spring washer 40 is proper, the frictional engagement between

washers

30, 32 and the slotted headband will allow sliding adjustment therebetween when the washers are gripped by one hand and the headband is pressed lengthwise by the other.

Even though the two studs 22 at opposite sides of the headset are required to move with the headband when it is swung from one of its ordinary positions of use to another, nevertheless, such swinging action of the headband is permitted by he rotational action of the ball-headed ends 220 of the studs embedded within their respective sockets 25.

For example, it may be the wish of a person servicing a jet aircraft to wear his headset for sound-attenuation purposes with the headband extending over the head, and thereafter he may wish to swing the headband into a position lying closely adjacent the nape of his neck, such as when a cap or protective helmet is also to be used, or he may wish to swing the headband to a position under his chin and such uses of the device, while in service may be readily and smoothly accomplished by merely exerting a firm pressure upon the headband.

In FIGS. 5 and 6, a somewhat modified form of the invention is shown. In these Figures at 121 is indicated a headband which has only one of its opposite end portions shown at end Each nd portion, it will be understood, is stamped or otherwise formed so as to be more or less of a spoon-shaped formation with the concave side thereof facing inwardly. It will be appreciated that a ball-headed stud 122, (like stud 22 in FIGS. 1-4) has its spherically-shaped inner end 122a embedded, during the earcup molding operation, in the plastic wall of the earcup 14 and so as to have limited universal swivelling motion as mentioned before, but, on the otherhand, hasits stem portion 122b slightly modified. This stem portion 122b, as shown, is straightsided and may be arranged, for example, to extend into a centered hole in the spoon-shaped central portion of the end and there securely rigidly connected to the central portion as by welding, riveting, peening or the like for effecting a firm mechanical connection. Thus, the ends of the headband will more or less hood-in the connecting means for the earcups. However, the same universal swivelling and pivotal motion of the earcups will be provided. When such permanent connections are used at the opposite end of the flexible headband, it will be preferable to employ in known manner an adjustable extensible arrangement for the headband intermediate the opposite ends. In such case, the headband would preferably have two semi-circular halves slidably related to each other and held together by a polyvinyl chloride channel, in known manner. Thus, the length of the headband may be changed readily as required.

Advantages afforded by this modified construction are that it is of less weight upon the wearers head and also that it may be constructed in a more economical fashion; nevertheless, each earcup may be swivelled or rotated into any one of its many different positions of adjustments and the headband may be easily and readily pivoted about the two ball-headed end portions of the studs embedded within the earcups into any position desired by the wearer merely by pressing on the headband. The smooth firm frictional engagement provided by the ball-headed studs within the earcup cavities will still be present and provide a firm gripping action sufficient to ordinarily retain the headband in any given operation position.

An important consideration of the present invention is the fact that the earcups are formed of any one of a number of well-known rigid thermoplastic or thermosetting materials by an injection molding process which embeds the spherically shaped end of the supporting studs 22 within the plastic material but, nevertheless, provides a firm gripping action of the ball portion thereof while also allowing desired dampened pivotal, universal swivelling and rotational movements therebetween. Furthermore, the amount of resistance to such motion may be easily and accurately controlled. Also, the construction is such that the joints so formed in the plastic material are self-lubricating and will remain substantially free from any penetration of dirt, dust or the like.

Each earcup is formed between complementary pairs of molds members recessed to provide a mold cavity within which is placed before the mold parts are closed the mounting stud 22 in such a manner that the greater part of the ball-headed portion thereof will become permanently embedded in the plastic material while, nevertheless, having the stem portion thereof remain free of the plastic and thus free to move relative thereto the desired or in any direction from its centered position.

In FIG. 7, two mold halves 131 and 133 are shown in engaging position ready to receive the plastic material for forming a molded earcup. It will be seen that the mold half 131 is provided with a finished formed surface 131a of predetermined desired size and shape and the mold half 133 is provided with finished mold surface 133a of a different predetermined complementary size and shape. These surfaces are suitably related so as to effect therebetween a mold cavity 135 of proper proportions for forming earcups like that shown at 14 in FIG. 1. A recessed portion 136 extends about the edge of the mold half 133 in such a way as to form a small peripheral retaining flange upon the finished earcup for aiding in engagement with the ear cushion 16 when same is later in place upon the earcup. A gate and passageway for the injection of the plastic are shown at 145.

Centrally of the mold half 133 is provided a tubular insert 137 which has a recessed upper surface 138 suitably shaped and arranged for forming the thickened central portion 24 on the outer wall 14a of the molded earcup (see FIG. 3) with the ball-headed end of the stud embedded therein. The tubular insert 137 is provided with a central bore 141 for receiving the stem portion of a stud each time an earcup is to be formed and before the mold members are closed for injection purposes. The ball-headed part 22a, at this time, rests upon a small upstanding collar 143 formed on the tubular insert so that the greater part of the ball-headed portion will be exposed within the mold cavity 135. The result is that the recess 27, indicated in FIG. 3, will be formed about the stem portion 22b for allowing the universal pivotal action of the stud mentioned above.

The size and thickness of the central part 24 of the earcup is such as to conveniently accommodate the enlarged polished ball-headed end portion 220 of the stud 22 (or 122a of stud 122) as the case may be. Flowable plastic material may be injected into the mold cavity in known manner though conduit means not shown and at such time air will be allowed to escape through ports or ducts in the mold part, likewise not shown.

The results are that during injection of the plastic material into the cavity, this material flows partially about the ball portion 22a of the stud 22 while forming the thicker part 24 and that when the mold halves are later opened and the rigidly formed earcup removed therefrom, the stud partially embedded within the plastic material will remain in the earcup when same is removed from the mold cavity. However, normal cooling and solidifying of the plastic material will cause the material to contract more firmly about the enlarged ball-shaped end portion of the stud and will provide a firm gripping action thereof. In fact, curing of the plastic over the next several weeks has also been found to increase slightly this firm gripping action.

The mold cavity surfaces are so shaped as to provide easy separation of the halves and easy removal of the cup as well as the stud 22.

Depending upon the size of the earcup and the amount of resistance desired with reference to its swivelling action and rotation, it is an easy matter in such an earcup and headband construction to control the amount of friction to be provided the ball-headed stud and the plastic of the cavity and this may be done merely by a change in diameter size of the ball being used.

Thus, if the weight of the earcups to be molded is increased, for example, in a particular model wherein greater sound attenuation is to be provided in comparison with the weight of a different lighter-weight model or is made heavier due to earphone being carried within the earcups, the frictional dampening resistance to swivelling action may be increased and easily controlled in amount by a change in the diameter of the ball-headed end of the stud to be used.

A small increase in the diameter of the ball-headed end will provide a relatively large increase in the amount of sliding areas being gripped and a large in crease in the frictional resistance provided the construction. The total frictional areas involved in any instance would be substantially equal to 4-rrr and thus doubling the diameter of the ball, for example, would result in at least a four-fold increase in torque required to rotate the stud.

Several different commercially available plastic materials which may be satisfactorily employed for forming rigid earcups are mentioned below and each is followed by a first column of numbers which represent ranges of coefficients of friction for these materials used in combination with polished stainless steel and a second column of numbers which represent ranges for the shrinkage factors for these materials.

Approx. per lineal inch Nylon 0.15 0.0090.015 Nylon (impregnated 0.20 ..001 0.005 with fiber glass) Delrin (Acetal Resin) 0.15 0.025 0.030 Teflon 0.04 0.003 0.060 Polyethylene 0.21 0.020 0.050 A.B.S. (acrylonytrile 0.15-0.25 0.003 0.008

Obviously, various combinations of coefficients of friction and of shrinkage factors will result in a wide range of available resistances to the rotation of the ballheaded stud. Thus, at least three different parameters are available to the designer:

1. Ball diameter 2. Coefficient of friction 3. Shrinkage factor for a constant molding cycle. While all of these plastics are very serviceable, the last mentioned may be preferred because it is less expensive to manufacture.

Laboratory tests of an earcup initially having a 12 ounce resistance to pivotal action of the stud embedded therein have provided, for example, after 250 revolutions of the stud in an orbital path at the rate of revolutions per minute an increase in resistance to 16 ounces and, furthermore, this increased resistance has remained substantially unchanged after 500, 750, and 1000 intermittent revolutions of such stud.

Having described my invention, 1 claim:

1. A headset comprising a flexible headband having opposite end portions, a pair of sound-attenuating earcups carried by said headband adjacent said opposite end portions thereof, each earcup being formed of rigid molded plastic material and having a solid outer wall peripherally integrally connected to an endless surrounding solid side wall, each side wall in turn carrying upon all parts of its endless inner edge a centrally apertured flexible head-engaging cushion so as to define with its earcup an enclosed sound-attenuating air space when each earcup is positioned against the wearer's head, and connecting means securing each of said earcups to said headband opposite end portions, each connecting means comprising a metallic stud secured to one of said headband end portions and having a smooth enlarged spherically-shaped inner end, a socket formed in the solid outer plastic wall portion of the earcup adjacent thereto, the major portion of said enlarged inner end being permanently embedded within said socket the rigid plastic material forming said socket providing a firm gripping action upon said spherically-shaped inner end which is such as to normally prevent relative movement between said earcup and said stud while allowing smooth relative movement therebetween when either is subjected to a small external force, said opposite end portions having elongated slots, each said stud of said connecting means extending through one of said slots, respectively, and a pair of friction washers providing a gripping action against the opposite sides of each of said end portions, one of said washers of each pair being secured to said stud so as to prevent rotation therebetween, said stud extending through said pair of washers, one washer of said pair of washers having a projecting rib and the other washer having a complementary recess therein, said rib extending through said slot into said complementary recess in the other washer of said pair of washers for preventing relative movement between said washers and said headband.

2.'The combination defined in claim 1 wherein an annular recess is formed in the plastic of said earcup around said stud adjacent the spherically-shaped inner end thereof, said recess being of such size as to allow universal swivelling action of said earcup about said spherically-shaped inner end a limited angular amount in any desired direction from its normal centered position.

Claims

1. A headset comprising a flexible headband having opposite end portions, a pair of sound-attenuating earcups carried by said headband adjacent said opposite end portions thereof, each earcup being formed of rigid molded plastic material and having a solid outer wall peripherally integrally connected to an endless surrounding solid side wall, each side wall in turn carrying upon all parts of its endless inner edge a centrally apertured flexible head-engaging cushion so as to define with its earcup an enclosed sound-attenuating air space when each earcup is positioned against the wearer''s head, and connecting means securing each of said earcups to said headband opposite end portions, each connecting means comprising a metallic stud secured to one of said headband end portions and having a smooth enlarged spherically-shaped inner end, a socket formed in the solid outer plastic wall portion of the earcup adjacent thereto, the major portion of said enlarged inner end being permanently embedded within said socket the rigid plastic material forming said socket providing a firm gripping action upon said spherically-shaped inner end which is such as to normally prevent relative movement between said earcup and said stud while allowing smooth relative movement therebetween when either is subjected to a small external force, said opposite end portions having elongated slots, each said stud of said connecting means extending through one of said slots, respectively, and a pair of friction washers providing a gripping action against the opposite sides of each of said end portions, one of saId washers of each pair being secured to said stud so as to prevent rotation therebetween, said stud extending through said pair of washers, one washer of said pair of washers having a projecting rib and the other washer having a complementary recess therein, said rib extending through said slot into said complementary recess in the other washer of said pair of washers for preventing relative movement between said washers and said headband.