CH668904A5 - PROTECT-TYMPAN WITH MULTIPLE FINS. - Google Patents

Description

DESCRIPTION

The present invention relates to an earplug with several fins of elastic polymer, useful as a hearing protector.

In the United States of America, one of the best known earplugs of the general type contemplated by the present invention is that known as "V-51 R", details of construction of this earplug being revealed in a report entitled Development of an Extra Small and Extra Large Size for the V-51 R Earplug, DT Blackstock and HE Von Gierke, April 1956, Aero Medicai La-boratory, Wright Air Development Center, Air Research and Deve-35 Operation Command, United States Air Force, WADC Technical Report 56-142. This earplug was developed during the Second World War to provide better hearing protection to members of the military who are subjected to percussive sounds, such as gunshots or explosions or 40 extremely noisy work such as in airports or aircraft maintenance facilities. The earplug V-51 R consists of an elastic elastomer, such as neoprene rubber, and includes a single rearward facing fin member which extends from the end of the nose of a rod member tubular 45 in rubber. The fin member extends rearwardly from the nose of the rubber tubular rod and is spaced therefrom to form a free annular space therebetween. In use, the eardrum is forcibly inserted into the ear canal, thereby at least partially collapsing the fin member extending backward into the underlying free annular space and shaping said fin member in acoustic sealing relationship with the retaining walls of the ear canal.

In U.S. Patent No. 2,427,664, to JY Dunbar and JS Knight, September 23, 1947, and to U.S. Patent No. 2,717,596 to JS Knight, 55 September 13, 1955, eardrums similar to earplug V are disclosed. -51 R described in the Blackstock et al report mentioned above. In FIGS. 2 and 3 of US Pat. No. 2,427,664, a tympanum protector is further represented comprising four disk-shaped fin elements with diameters 60 increasing in series which extend substantially transversely to the support rod member. As is more clearly visible in FIG. 3, the four elements forming the fins of the construction are revealed as being able to be inserted into the ear canal and are urged a little towards the rear by its retaining walls.

Unfortunately, earplugs of the type disclosed in the above publications and in their variants known to the present holder often have several drawbacks. First, when

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668904

that they are worn appropriately, a significant proportion of the user population often experiences discomfort in the use of such tampons. In general, this discomfort is perceived in the form of excessive pressure on the walls of the ear canals, which pressure can be great enough to be painful. The response of a current user to this discomfort consists in removing the eardrum which bothers him from the ear canal to the point where the perceived excess pressure is removed and, when this is done, almost always the acoustic joint between tampon and the ear canal is broken or weakened, thereby destroying or at least compromising the desired hearing protection function of the eardrum. It is a particularly pernicious impairment because, while the respondent appeared, from the outside, to be hearing protected enough, in fact, he may not be protected at all. Second, due to the well-known anatomical variability of the dimensions and shapes of the ear canals throughout the population, including the variability that often exists between the ear canals of an individual user and the variations in size of the individual ear canals that occur of course, it usually means that the finned eardrums are produced in a number of dimensions and carefully adjusted by trained personnel to ensure that competent hearing protection is achieved. For example, the V-51 R pad mentioned above is currently produced in five different and distinct dimensions which, according to the Blackstock et al report mentioned above, provides the ability to adapt appropriately to 80-85 % of adult male users. Obviously, this condition of production of the multiple dimensions of a eardrum protector greatly adds to the price and the complexity of its manufacture. According to the present invention, there is provided a multi-fin eardrum which can be produced in one dimension while fitting comfortably and providing effective hearing protection for the vast majority of the population.

The main object of the present invention is to provide a new ear protection with several fins.

Another object of the present invention is to provide a new construction of a tympanum protector with several fins, comfortable to wear in an appropriate manner and offering an effective acoustic sealing of the ear canals.

Another object of the present invention is a multi-fin eardrum which can be produced in a single dimension, which earhook will suitably and comfortably fit 98% of the total adult population of users.

Another object of the present invention is a multi-fin eardrum where the fin members can be easily manipulated to expose normally hidden parts of the eardrum for cleaning.

The objects are achieved by the earplug according to the invention, defined by claim 1.

A multi-fin eardrum made of a flexible elastic polymeric material is provided, said eardrum comprising a rod member carrying a series of at least three hollow fin members directed backwards and spaced apart by substantially cross sections circular, the first of these elements extending from the end of the nose of the rod-like member. Each of the fin elements of the series comprises a skirt of relatively thin uniform thickness and is made of an elastic and flexible polymeric material having a Shore Durometer hardness value of between approximately 10 and approximately 90. The fin elements of the series increases in diameter, starting from the end of the nose of the rod-forming organ. The diameter of the rod member located below each fin member is chosen to form a free annular space between the internal surface of the skirt of the associated fin member and the rod member of sufficient size. to allow said skirt portion to sag in and occupy said space upon insertion of the eardrum into the ear canal.

The invention will be better understood, and other objects, characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended schematic drawing given solely by way of example illustrating several embodiments of the invention and in which:

- The single figure is a schematic longitudinal sectional view of a earplug according to the invention, comprising various preferred embodiments thereof.

Referring to the drawing, the eardrum of the invention generally comprises a rod member 1 and a series of at least three rear wing elements spaced rearwardly spaced 10, 20 and 30, each having usually a circular cross section. Preferably, each fin element of the series extends rearward from its point of attachment to the rod member 1 in an arcuate manner in a convex shape and, more preferably, will be of generally hemispherical conformation. By “generally hemispherical”, it is indicated that the fin element does not define less than approximately 45% and not more than approximately 55% of a hollow spherical body sectioned with cord whose external surface is, in all its essential points, appreciably equidistant from its only geometric center. The earplug of the invention can be made by any suitable polymer molding technique, such as by injection molding. The key to achieving the benefits of the invention is the choice of the elastic polymeric material used in the manufacture of at least the skirts 12, 22 and 32 of the fin elements 10, 20 and 30. This material must have a hardness value at Shore A durometer (by the technique of ASTM 2240-81) of between approximately 10 and approximately 90 and preferably between approximately 30 and approximately 60. The rod member 1 may of course be made of an elastic polymeric material of the same type that that used for the skirts of the fins 12, 22 and 32 or, if desired, can be composed of an elastic polymeric material having a hardness value on the Durometer Shore A slightly higher, say up to about 100. In a preferred embodiment of the invention, the construction material of the rod member 1 will have a Shore Durometer hardness value of between approximately 50 and approximately 70. In another preferred embodiment of the invention , however, for r ease of manufacture, it will be preferable to use a single polymeric material for the entire construction.

Obviously, there are many known elastic polymeric materials which can be used effectively in the manufacture of the earplugs of the invention. For example, natural rubber, neoprene rubber, SBR (styrene-butadiene) rubber, silicone rubber, EPDM (ethylene-propylene-diene) rubber, polybutadiene rubber, polyurethane elastomers, elastomers ethylene vinyl acetate, elastomers based on acrylic acid precursors, and vinyl halide polymers are all generally suitable building materials generally available from commercial sources having the durometer values Shore A or which can be mixed appropriately (for example by internal and / or external plasticization) in order to give them the necessary hardness values. Particularly preferred polymeric materials are thermoplastic silicone rubber compositions, as represented by a family of thermoplastic elastomers for injection molding sold under the trade name C-FLEX (registered trademark), Concept Polymer Technologies, Inc., Clearwater , Florida. These silicone rubber compositions are available in a considerable range of hardness values from the Shore A Durometer, can be thermally received in complicated forms by any conventional thermoplastic molding technique and the articles produced therefrom can generally be sterilized or cleaned without degradation. Another preferred material for building the earplugs of the invention is a block copolymer of thermoplastic SBR as produced and sold in a number of grades.

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668,904

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under the name KRATON, by Shell Chemical Company, Synthetic Rubber Division, NY, New York.

The first fin element 10 extends outwards and towards the rear of the end 3 of the nose of the rod member 1, thus defining a uniformly thin skirt 12 which is spaced, along its length, by the part of the rod member 1 which is located below. The second fin member 20 extends outward and backward from a first intermediate location along the length of the rod member 1, thereby defining a uniformly thin skirt 22 which is spaced along its length , of the part of the rod-forming member 1 which is located below. Likewise, the third fin element 30 extends outwards and rearwards from a second intermediate location along the length of the rod member 1, so as to define a uniformly thin skirt 32 which is spaced apart, along its length, of the part of the rod-forming member 1 which is located below. As will be noted in the drawing, the basic parts 16, 26 and 36 of the skirts 12, 22 and 32 respectively, in other words, the points of junction of the interior surfaces of the skirts with the rod member 1, are preferably shaped so as to form a minimum radius between them, in connection with good molding practices, thereby reducing the thickening and the consequent stiffening of the building material at these points. This design feature of the construction not only assumes that the skirts 12, 22 and 32 have maximum flexibility at these base portions but also gives the skirts 12, 22 and 32 a desirable ability to turn "beyond the center", whereby each skirt can be easily manipulated in order to be returned from its normally rearward orientation to a forward orientation. When they are thus turned forward, the interior surfaces of the skirts and the parts of the rod member 1 normally located below these skirts are exposed, thereby giving the user the ability to inspect and / or to easily clean areas of the eardrum that are normally hidden.

It should also be noted that the diameters of the hollow elements forming fins 10, 20 and 30 increase in series and that, in a preferred embodiment of the invention, said elements are spaced along the length of the rod member 1 so than,

in the finished eardrum, only one straight construction line, L, can be drawn in order to be at least in point contact with all the fin elements of the series. In this preferred embodiment, these diameters and intervals are also chosen so that the half-angle 0 defined between said construction line L and the axis CL extended towards the front of the rod-forming member 1 is located in the range between 10 and 16 °, the preferred range for the half-angle 0 being between approximately 12 and approximately 14 °. By adhering to these dimension criteria, it is ensured that the eardrum constructed in this way will be usable by and effective for the vast majority of the user population. For example, when the half-angle 0 is 13 °, the elements forming the fins are generally hemispherical and the radius of the first element forming the fins 10 is approximately 4.19 mm, it has been found that the eardrum of the invention could produce acoustically effective joints up to 98% of the total adult population, including women.

It will be apparent to those skilled in the art that many of the functional benefits of the present invention arise, at least in part, because the fin elements of the construction are endowed with the ability to deform elastically in use , to the point necessary under relatively weak and essentially linear forces exerted by or reflected in the walls of the ear canal when inserting the eardrum. Thus, there is a complex interaction between the specific geometries and the dimension of the elements of the construction of the eardrum in combination with the hardness (s) of the elastic polymer building material (s) used here. Consequently, it is not only important that the building material used for each of the skirts 12, 22 and 32 has a Shore Durometer hardness value of between approximately 10 and approximately 90,

but it is also important that the thickness of each of said skirts 12, 22 and 32 is in the range of about 0.20 mm to about 1.27 mm. While no hard and fixed construction rule can be imposed from this point of view, in general terms, the more flexible the construction material, the greater the thickness of the skirt 12, 22 and 32. When building materials falling within the preferred range of Shore A durometer hardness values between about 30 and about 60 are employed, it has been found that the benefits of the invention generally arise substantially when the thickness of each of the skirts 12,22 and 32 is in the range of 0.76 mm to 0.30 mm. Obviously, the right thickness balance for each of the skirts 12, 22 and. 32 and the Shore A Durometer hardness value of the elastic polymer construction material can be easily determined experimentally. In a preferred embodiment of the invention, it has been found that a nominal thickness of approximately 0.50 mm of each of the skirts 12, 22 and 32 and the use, for this, of a building material in Elastic polymer having a Shore A Durometer hardness value of about 40 resulted in a construction of a earplug having an excellent general combination of effective acoustic sealing and user comfort properties.

As previously mentioned, the diameter of the part of the rod member located below each of the skirts 12, 22 and 32 of the fin elements 10, 20 and 30, respectively, is chosen so as to form a free annular space 11, 21 or 31 below, free space in which said skirt can be deformed during the insertion of the eardrum into the ear canal. The specific dimensions of the free annular spaces 11, 21 and 31 are not particularly critical, provided, of course, that each is adequate to fulfill the above function. However, it is generally desirable for each free annular space to have a dimension, determined by subtracting the diameter of the underlying rod member from the internal diameter of the open end of the skirt and dividing the result by two, at least minus twice the thickness of the particular skirt 12, 22 or 32 and arranged over it. By “free annular space”, it is indicated that the annular space 11, 21 or 31 does not contain any element or material which would tend to obstruct or restrict the movement of the associated skirt.

With the above in mind, it is within the scope of the invention to form the rod member 1 with a single uniform diameter. However, when this is done, it will be evident that considering the free annular space below each fin skirt, this will ordinarily dictate that the uniform diameter chosen for the rod member 1 is based on a consideration of l free annular space for the smallest skirt, in other words the skirt 12 of the fin element 10 of the nose. Thus, unless the envisaged constant diameter rod member is formed from a relatively stiff elastic polymeric material, such as a material having a Shore A durometer hardness value of more than about 50, it can be found that the resulting construction of the eardrum may be somewhat flaccid along the rod member 1 and that said rod member will not provide sufficient support for the second and third fins 20 and 30 to allow them to be easily inserted into the ear canal only by manipulation of the rod organ. For these reasons, it is then generally preferable for the diameter of the rod member 1, in particular if it is formed from a building material having a Shore Durometer hardness value of less than about 50, to increase gradually backwards from one fin element to another, thereby gradually stiffening the part of this member supporting the fin elements.

In order that the eardrums of the invention can be easily inserted and removed from the ear canal, it is desirable that the rod member 1 extend rearward over any suitable length beyond the rear edge 34 of the the rearmost fin element 30 so that its rearmost part defines a tip 42 which can be easily grasped between the thumb and the index finger of the user.

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It is often desirable to provide pairs of earplugs connected to each other by a length of a flexible cord. Such a construction of attached eardrums can be used to prevent an accidental fall or loss. This can be important, for example, if the eardrums are to be used in an industrial food processing environment or in an environment where a fallen eardrum could be so dirty that it would be rendered unusable or even lost. In order to obtain such a construction of attached eardrums, the free end 40 of the rod-forming member 1 may be provided with a groove or opening 41 oriented axially of a dimension adapted to receive the end of a length of a flexible cord (not shown). This cord can be fixed in the groove or opening 41 by any suitable means, for example by thermal or solvent welding or by using an appropriate adhesive or by the use of a cord whose ends have a diameter a little larger than the diameter of the receiving groove or opening 41, thereby forcing the elastic polymer material surrounding the groove or opening 41 to elastically grip the ends of the cord in a secure manner. For further general details relating to the constructions of the attached eardrums, reference may be made to a literature such as: US Patent No. D-241,881 in the name of Peterson and others; US Patent No. 4,193,396 to Wacker; U.S. Patent No. 4,219,018 to Draper, Jr.; US Patent No. D-245,202 in the name of Asker.

In addition, while the eardrums according to the present invention can, as previously indicated, be used as individual articles which can be inserted into the ear, they can also be used as plug elements of a protective device. Hearing aid comprising a generally U-shaped spring headband at the free ends of which the plug elements are fixed in an inward direction. In this embodiment, the eardrums of the invention are inserted into the ear canal of the user and are maintained under the continuous forces of stress directed towards the inside of the spring headband. Other details relating to hearing protectors of this general type can be obtained by referring to literature such as US Patent No. 4,461,290 in the name of Gardner, Jr. et al., Or British Patent No. 1 355,052 on behalf of Metal Box Company, Ltd.

Using the above principles of construction and for purposes of non-limiting examples, a number of three-fin eardrums substantially conforming to the drawing have been produced by injection molding of a thermoplastic silicone rubber [elastomer C-FLEX (registered trademark)] having a hardness value on the Shore A Durometer of around 40. Referring to the drawing, the dimensions of the eardrums thus obtained are given below:

Total length of rod member 1

30.05 mm

Diameter of the rod-forming member 1 at the end

moth 40

5.15 mm

Diameter of rod member 1 below

skirt 32

5.15 mm

Diameter of rod member 1 below

skirt 22

4.78mm

Diameter of rod member 1 below

skirt 12

3.40 mm

668,904

Radius of the hemispherical fin element 10

4.19

mm

Radius of the hemispherical fin element 20

5.15

mm

Radius of the hemispherical fin element 30

6.48

mm

Axial length of the hemispherical fin element

risk 10

4.42

mm

Axial length of the hemispherical fin element

risk 20

5.23

mm

Axial length of the hemispherical fin element

risk 30

6.65

mm

Thickness of skirts 12, 22, 32, each

0.48

mm

Length, nose 3 to end 24

9.78

mm

Length, nose 3 to end 34

16.48

mm

Annular space 11

2.16

mm

Annular space 21

2.28

mm

Annular space 31

3.43

mm

Half angle 0

13

0

The eardrums were tested according to the ANSI S3.19-1974 testing process using ten subjects. In the first series of tests (hereinafter referred to as "maximum comfort tests"), subjects were instructed to insert the pads into their ear canals only up to the point of maximum comfort perceived by the user. In the second series of tests (hereinafter referred to as “maximum attenuation tests”), the subjects were equipped individually by a technician trained to the point of maximum acoustic sealing of the ear canals by the pads. The maximum comfort test gave an NRR value of 22 while the maximum attenuation test gave an NRR value of 25.

During the maximum comfort test, subjects were asked to judge the relative comfort of the ear protectors in place according to the following scale:

COMFORT LADDER OF THE HEARING PROTECTION DEVICE

Very comfortable

Comfortable

Without opinion

Uncomfortable

Annoying

0 1

2 3

4 5 6

7 8

9 10

The average comfort rate given to the earplugs of the invention by the subjects was approximately 3.

For comparison purposes, a similar series of tests was carried out with the same frame of subjects using a prior art multi-fined earplug. The maximum comfort test gave an NRR value which was only 16. The maximum attenuation test gave an NRR value of approximately 23. The maximum comfort score given to these commercial eardrums by subjects during the maximum comfort test was approximately 4.

Another test of maximum comfort was carried out with the same frame of subjects using another earplug with several fins marketed in the prior art. The NRR value was around 13 and the average comfort rating given to earplugs was around 6.

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1 drawing sheet

Claims (17)

668,904 2 1. Ear protection made of elastic polymer material and comprising: an elongate rod member (1) having a nose end (3); a series of fins (10, 20,30) comprising at least three rear fin elements extending backwards, of substantially circular cross sections and of increasing diameter, which are integrally fixed to said rod member at intervals spaced along at least part of its length, the finest diameter element being placed at said nose end, characterized in that each fin element comprises a thin skirt (12, 22, 32) having a substantially uniform thickness between 0.20 mm and 1.27 mm, of hemispherical shape and consisting of a building material made of an elastic polymer having a Shore A durometer hardness value of between 10 and 90; the diameter of each part of said rod member below each skirt being such that this defines a free annular space between the interior surface of said skirt and said rod member. 2. earplug according to claim 1, characterized in that the interval between the elements forming the fins and their diameter are such that a straight line of construction can be drawn which is at least in point contact with each of the elements d 'fin of the series and said construction line intersects the extended axis forward of said rod member to define a half angle. 3. Earplug according to claim 2, characterized in that the aforementioned last angle is between 10 and 16 °. 4. Earplug according to claim 2, characterized in that the aforementioned half-angle is between about 12 and about 14 °. 5. Earplug according to claim 1, characterized in that the building material of each of said fin elements of the series has a Shore Durometer hardness value of between 30 and 60. 6. Earplug according to claim 5, characterized in that the thickness of the skirt of each fin element is between 0.76 mm and 0.30 mm. 7. Earplug according to claim 1, characterized in that the construction material of each skirt has a durometer value at Shore Durometer A of about 40 and where its thickness is about 0.50 mm. B. Earplug according to claim 1, characterized in that the diameter of each part of the abovementioned rod member below each skirt increases towards the rear from one fin element to the other. 9. Earplug according to claim 8, characterized in that the building material of an elastic polymer of the aforementioned rod member has a Shore A durometer hardness value of less than about 50. 10. Earplug according to claim 1, characterized in that the elastic polymer building material of the above-mentioned rod member has a Shore A durometer hardness value of between 50 and 70. 11. Earplug according to claim 1, characterized in that the dimension through each free annular space is at least twice the thickness of the associated skirt. 12. Earplug according to claim 1, characterized in that the aforementioned rod member extends towards the rear of the last of said fin elements over a length sufficient to define a tip means by which the handle can be manipulated. earplug. 13. earplug according to claim 12, characterized in that the free end of the aforementioned rod member comprises an axially oriented groove of a size adapted to receive one end of a length of a flexible cord serving 'attached. 14. earplug according to claim 1, characterized in that the junction of the inner part of the aforementioned skirt of each fin element of the series with the abovementioned rod member is of a minimum radius, thereby reducing the thickening of the construction material at said junction and for giving said skirt the capacity of manual eversion towards a conformation extending forward, whereby the interior surface of said skirt and the portion of said rod member which is below are exposed. 15. Earplug according to claim 1, characterized in that along the elongated rod member the spacing of the ele- io ments of hemispherical fin is provided so that the outer edge of each skirt is in the plane of the top of the fin element of hemispherical shape next or more distant. 16. eardrum according to claim 1, characterized in that along the elongated rod member the spacing of the fin elements of hemispherical shape is provided so that the outer edge of each skirt slightly covers the top of the next hemispherical fin element. 17. Earplug according to claim 1, characterized in that it consists of a thermoplastic silicone rubber.