US Patent References:
EarplugFornet - February 1952 - 2587035
EarplugZwislocki - August 1957 - 2803247
Ear plugBecker - September 1958 - 2850012
Description:
This invention relates to an acoustically absorbent ear plug which is very effective, comfortable, and convenient to use.
Previously, considerable difficulty had been experienced in providing a satisfactory ear plug. Previous ear plugs have generally been unsuitable for their intended use because they were ineffective in absorbing noise, or they were uncomfortable or dangerous to wear for extended periods of time.
These and other disadvantages of the prior art have been overcome according to the present invention.
According to the present invention, a predetermined quantity of nonslumping silicone putty is encased in a very thin film of thermoplastic polmeric material. The film is initially in the configuration of a flat sheet so that when it is gathered together around the silicone putty, it will be stretched or drawn over one end of a generally elongated body of putty, folded along longitudinal lines on the exterior of the putty, and gathered together at the opposite end of the putty body. The gather at the opposite end of the body is conveniently tied off with a thread or strip of thermoplastic polmeric material, and the fringe of the plastic film extending beyond the tie is preferably heat-shrunken into a knob which may be partial y fused with the tie member. This seals the putty in the film cocoon and also provides a convenient handle for removing and inserting the ear plug.
The entire ear plug, with the exception of the fused knob, is very malleable over an extended range of temperatures. There are no sharp ridges in the ear to cause discomfort to the wearer. The nonslumping silicone putty has substantially the same degree of plasticity over the entire range of temperatures normally encountered under conditions where ear plugs are worn. The nonslumping silicone putty will not flow within the ear during use. Once inserted in the ear canal, ear plugs of this invention retain their shape and do not flow or creep down against the ear drum.
In the drawings there is illustrated:
FIG. 1, an ear plug of this invention;
FIG. 2, a silicone putty body;
FIG. 3, a synthetic organic polmeric film in sheet form;
FIG. 4, a synthetic organic polmeric tie off element;
FIG. 5, a partially assembled ear plug; and
FIG. 6, a cross-sectional view taken along line 6--6 in FIG. 1.
Referring particularly to FIG. 1, there is illustrated an ear plug, indicated generally at 14. Ear plug 14 is generally elongated in configuration and is provided with a tip end 16, which is adapted to be inserted foremost into an ear canal, and a base end 18, which is adapted to be grasped by the user for purposes of insertion and removal from an ear canal. Typical longitudinal folds 20 extend longitudinally of ear plug 14 and define shallow channels or discontinuities in the exterior surface of ear plug 14. Ear plug 14 is composed of a body 10, film 12, and tie member 22. Body 10 is composed of an acoustically absorbent, readily malleable, nontoxic, substantially nonslumping material having a substantially constant viscosity or degree of malleability over a wide range of temperatures of from at least about 10° centigrade to 75° centigrade. Nonslump silicone polymers are generally preferred for use as body 10.
Ear plug 14 is conveniently formed by molding body 10 to the desired configuration, placing it in the approximate center of a sheet of supple film 12 and gathering the film around one end of the body 10. The film is tied at the gathered end, as shown in FIG. 5, by means of tie mmber 22, leaving fringe 23 extending beyond the tied gather. Tie member 22 is conveniently a thermoplastic thread or strip of material. The fringe 23 is subjected to heat so as to shrink it and fuse it into a knob 24, which serves as a handle by which ear plug 14 may be grasped for insertion and removal from an ear canal.
The body 10 is generally sufficiently tacky so that film 12 adheres to the exterior surface of body 10, except where the film 12 folds together so that the inner surface of film 12 is not in contact with body 10. This insures that film 12 will not balloon away from the surface of body 10. Film 12 is preferably capable of being stretched so that it will not rupture if body 10 is deformed in use to such a configuration that it requires film 12 to stretch. The cocoon like covering formed by film 12 is continuous and completely encapsulates body 10 once it has been tied and fused to produce knob 24. In order to avoid discomfort and injury to the wearer of the ear plug, film 12 is preferably a very supple, water impervious, nontoxic, thermoplastic material having a thickness of less than about one mil. Suitable films include, for example, polyethylene film having a thickness of about one-half mil or less.
Preferably both film 12 and tie member 22 are organic polmeric thermoplastic materials. This greatly facilitates the sealing of the film 12 around body 10 and also the formation of knob 24 because only heat is required to fuse fringe 23 to form knob 24 and seal the ear plug 14.
In use the ear plugs of this invention are preferably wetted with water prior to being inserted into the ear canal. This should be done to insure obtaining a good seal between the ear plug and the wall of the ear canal. As the ear plug is inserted, pressure is built up within the canal between the ear drum and the tip end 16 of ear plug 14. This pressure is relieved by the expulsion of air along longitudinal folds 20. Likewise, when the ear plug is to be withdrawn, the production of a vacuum within the ear canal is prevented by drawing air through longitudinal folds 20 into the ear canal. During insertion the ear plug is conformed to the shape of the ear canal. This shape is maintained while the ear plug is being used because the body 10 does not slump or flow along the ear canal. Since the thin film 12 is water proof, washable, and sanitary, it may be reused several times. The preferred, readily deformable silicone putty, from which body 10 is prepared, is nontoxic so that the ear canal is not injured even if the film 12 is ruptured in use.
In forming the heat-sealed flange, it is generally preferable to fuse a portion of the tie member into the flange. This minimizes the chance of tearing film 12 during formation and use.
Preferably, where the polmeric silicone used as body 10 is an inherently nonslumping material, it is used without diluent or filler. Where the body 10 is composed of a material which tends to slump or flow with time, it is preferable to include a filler, such as, for example, cotton flock, to stabalize body 10 against flowing. The unfilled, nonslumping silicone putty is preferred because it tends to be more malleable and produces a better seal with the ear canal than does the filled putty.
Ear plugs of this invention find particular use in industrial plants and shooting ranges. They are also suited for use by students and light sleepers. In general, these ear plugs are useful wherever it is necessary or desirable to block out unwanted sound.
As will be understood by those skilled in the art, what has been described are preferred embodiments in which modifications and changes may be made without departing from the spirit and scope of the accompanying claims.