SE443505B - HEARING PROTECTION WITH SPRING HEADBANDS - Google Patents

Description

8006942-0 with a resilient or elastic filling material. The second end portion of each means for contact with the ear canal comprises an end cap which is attached to the plug portion, engages the plug portion and has a cavity and a channel leading to the cavity, which channel has a chamfered surface which widens in direction from the cavity, which cavity extends inside the open outer end of the plug part in such a way that the tendency of the means for contact with the auditory canal is reduced. The opposite ends of the headband each have an inwardly directed segment with an end ball at its end and a joint connecting the cavity of each lid with resp. end ball on the headband, whereby the means for contact with the ear canal can swing around the joint point and can form to the ear under the pressure of the headband, each joint having a center point which is centrally located inside the end cap, which chamfered surface is a conical abutment surface for limiting the tilting of the contact means. Due to the spring action of the headband, the plugs are partially pressed into the ear canal and block it.

The invention is described in the following with reference to the accompanying drawings, in which Fig. 1 is a schematic front view of a hearing protector according to the invention, Fig. 2 is a schematic longitudinal section of a hearing plug 20 in Fig. 1, and Fig. 3 shows a schematic longitudinal section of yet another embodiment of the earplug 20j.figJ. In Figs. 1 and 2, in which similar parts have the same designation, the hearing protector according to the invention generally comprises a U-shaped headband 1, to the ends 3 and 5 of which are attached inwardly directed earplugs 20 for the ear canal. The attachment of the earplugs 20 to the end portions 3 and 5 is hingedly arranged to enable the earplugs to be inclined horizontally and vertically. Each earplug 20 includes a soft, smooth, resilient and hollow capsule 22, the size and shape of which are adapted for partial insertion into the ear canal. Due to these properties, under the action of the resilient headband, the plugs 20 are partially pressed into the ear canals and clog them.

Due to the articulated attachment of the plugs 20 to the end portions 3 and 5 of the headband, the plugs are free to tilt and correspond to the natural angles of the ear canals on the wearer, so that they slide in there with the greatest clogging effect and without the need for external adjusting from the wearer's side. This is a significant advantage of the hearing protection according to the invention because the hearing aids of different carriers are not completely bilaterally symmetrical. In addition, it has been found that prior art hearing protectors often require significant adjustment of the contact means in the ear canals to provide the greatest blocking effect and that these adjustments are often performed without care or completely neglected so that the wearer does not achieve the hearing protection effect. give. With the hearing protection according to the invention, however, these adjustments, which can be quite small, take place automatically.

The essential function of the substantially U-shaped headband 1 is, of course, to act as a carrier for each earplug 20 and as a spring for pressing the headplugs 20 to block the ear canals. With these purposes in mind, therefore, the shape, construction, and material in the manufacture of the headband 1 are obviously subject to considerable variation. The headband 1 can e.g. be assembled as a metal spring in a single piece or in several parts.

For example. For example, two curved leaf springs can be arranged overlapping and slidable so that they form a U-shaped spring of adjustable length.

However, in view of the desired light weight and one-piece construction, it is desirable that the headband 1 be suitably molded from a rigid, resilient polymer, preferably a thermoplastic such as a rigid polyvinyl chloride or polyacetal. The construction is therefore a simple manufactured headband 1 of light weight, which at the same time provides sufficient and durable suspension for it to be able to push in and keep the plugs 20 in blocking engagement with the ear canals during the entire service life of the hearing protector.

It has been found that the spring force from the headband 1 on the plugs 20 under conditions of use is significant in that the spring force must be sufficient to provide effective blockage of the ear canal but at the same time so low that it does not cause the wearer discomfort. Thanks to the design of the plug 20 according to the invention, this spring force does not have to be large and therefore contributes significantly to the wearer's comfort with the hearing protectors according to the invention. We have e.g. found that a suitable spring force for the plugs 20 is obtained, so that the headband has such a structure and composition that when its opposite, free ends (delimited by the balls 7 and 9 in Fig. 1) are kept separate at a distance of 14, 35 cm, the headband produces an inwardly directed spring force of between 50 and 300 g and suitably between 100 and 200 g. A suitable measurement of the spring force is made by holding one end of the headband in a fixed position while its other end is pulled out to the determined distance by means of a spring wave. Similarly, the measurement can also be made by holding one end of the spring band 1 in a fixed position while its other end below the fixed end is gradually loaded with known weights until the determined distance of 14.35 cm is reached. The spring force is regulated by appropriate dimensioning of the headband in the choice of construction material and a combination of both.

The construction of the earplugs 20 is essential according to the invention for the plugs to have such a size and shape as is suitable for partial insertion into the ear canals so that at least the insertable parts comprise a smooth, soft, resilient and hollow capsule 22. With regard to these The capsule 22 is composed of a soft, smooth and resilient elastomer or plastomer such as plasticized polyvinyl chloride, silicone rubber, ethylene-vinyl acetate copolymer, styrene-butadiene block copolymers, ethylene-propylene diene rubber, neoprene rubber, polyurethane rubber or similar rubber. The hardness of the material of the capsule 22, determined at room temperature by Shore A hardness meter according to ANSI / ASTM D 2240-75, may range from about 10 to about 80 and should suitably be in the range of from about 20 to about 50.

Suitably the capsule 22 has a conical shape. When using a conical capsule 22, the small end of the capsule will of course form the retractable free end of the earplug 20 while the * W large end serves for attachment to the end portion 3 or 5 of the headband 1. The cone angle of the capsule 22 may be in the range. ° to about 4s ° with the appropriate range being from about 200 to about 30 °. The small end of the capsule 22 may have a diameter of between about 3 to 10 mm and is suitably in the range from about 5 to 7.6 mm. 8006942-0 The inner volume of the capsule 22 may be empty or is suitably filled with a resilient filling material 26. When the capsule 22 is hermetically sealed, the filling material 26 may be a liquid such as water or oil but it may also be air. Suitably, however, the filler material 26 is a resilient solid or semi-liquid material such as silicone or grease, glass wool, polyester fiber, polyurethane foam, polyvinyl chloride foam or the like. A particularly useful material as filler 26 in the hearing protector of the invention is an externally plasticized polyvinyl chloride foam, the nature and concentration of the plasticizer being such that it gives the final foam the property of slowly regaining its deformed shape and of giving a low return pressure upon deformation.

The wall thickness of the capsule 22 can vary considerably and is usually not critical to the fulfillment of the advantages of the invention provided that its resilient properties are preserved. In general, the thickness can be between 13/1000 and 76/1000 mm and is suitably in the range between 25/1000 to 50/1000 mm.

According to the invention, it is further essential that the hearing plugs 20 are articulated to the end portions 3 and 5 of the headband 1 so that the plugs 20 can tilt freely both horizontally and vertically under the action of the spring force from the headband 1. In general, any articulated fastening device said freedom for tilting the plugs 20, suitable for use in the construction of the invention and many such devices may be available to the person skilled in the art. Then e.g. the plugs 20 be attached to the end portions 3 and 5 of the headband 1 by means of springs, hinges, universal joint or the like. However, the fastening device is suitably such that the free ends of the earplugs 20 can describe a path in a plane which is approximately normal to the plane delimited by the headband 1. A suitable polymeric guide device comprises a short, flexible pin of a polymer such as for example polypropylene or silicone rubber having one end attached to an end portion 3 or 5 of the headband 1 and the other end attached to the earplug 20. Another generally suitable fastening device comprises a light coil spring, one end of which is attached to one end 3 and 5 and the other end of which is attached to the plug 20.

The preferred hinge device consists of a ball joint according to the figures. In this device, the end parts 3 and 5 of the headband 1 are provided with end balls 7 and 9. The balls 7 and 9 may be special elements in the structure of the headband 1 or be formed connected to the belt. The outer end of each earplug 22 includes a socket 28 with a spherical cavity 30 whose diameter is adapted to receive the balls 7 or 9. It is desirable that the joint center of the earplug 20 against the end portion 3 or 5 of the headband 1 be inside rather than outside the outer end of the plug Namely, this reduces the tendency of the plug 20 to deviate from the spring force from the main band 1. In the embodiment according to Fig. 2, the center of the spherical cavity, which forms the joint center, lies in the plane delimiting the outer ends of the capsule 22 and is thus below the outer end of the plug 20. The channel 32 to the cavity 30 is tapered outwardly so as to define a conical stop surface 34 for limiting the inclination of the hearing plug 20. The material of the base 28 is suitably resilient enough to allow the ball 7 or 9 to be pushed into the cavity 30 by pressing. Therefore, the base 28 of the plug 20 is suitably formed of an elastic polymeric material, which for the sake of simplicity may be of the same type as in the capsule 22.

It should be noted that although the term "headband" here refers to the structure designated 1, the term does not limit the use of this structure. For example, the hearing protector may be used with the headband 1 arranged directly over the wearer's head but give substantially as good In some cases, such as when the wearer also has to wear a bulky helmet, respirator or eye protection, arrangement of the headband l either behind the neck or under the chin may be necessary. of the invention is shown in Fig. 3. Here is a plug 20, a capsule 22 with internal volume 24, a filling material 26 and a base 28. The base 28 comprises a connecting part 36 and a joint part 38. The connecting part 36 comprises what has been said for articulated attachment.

The joint part 38 is intended for attachment to the capsule 22.

The connecting part 36 and the joint part 38 are separated by means of a part 40 and a volume 42. The volume 42 provides a more flexible base, which is grippable and slidable with greater convenience and therefore a more comfortable plug. The connecting part 36 and the joining part 38 come into contact with each other when the plug is gripped and pushed into the ear canal.

Here are a number of illustrative, non-limiting examples.

Example 1 The outer elements of the two plugs 20 of the type shown in Fig. 2 were made by die casting of a two-component, dust-treated silicone rubber (Silastic Q-3 ~ 959l, manufactured by Dow Corning Corp., Midland, Michigan). Heat treatment in the mold took place at a temperature of about 177 ° C for about 10 minutes. At room temperature, the Shore A hardness of the heat-treated material was about 60. The essential dimensions of the external elements were as follows: Capsule 22 length 2.6 cm diameter at the small end 0.64 cm 'diameter at the large end 1.47 cm wall thickness 0 .04 cm convex 2s ° 8006942-0 8 k Base 28 length 1.37 cm diameter in the cavity 30 0.64 cm cone angle 34 of the duct 600 The volume 24 in the capsule 22 was filled with a cylindrical plug, which in unloaded condition had a diameter of about 1.37 cm and a length of about 1.8 cm, the plug being composed of a highly plasticized cell polyvinyl chloride with substantially closed cells. The plug was inserted after rolling the plug between the fingers, after which it was pushed into the volume 24, after which the plug was allowed to expand. Then, the base 28 was glued to the capsule 22 by means of a silicone rubber-curing silicone rubber at room temperature.

The substantially U-shaped headband 1 was made of rigid polyvinyl chloride by injection molding the plastic into the shape shown in Fig. 1. The diameter of the cast strip was 0.48 cm. The radius of curvature of the upper part of the headband 1 was 6.35 cm while its straight parts had a length of about 8.75 cm and the end parts 3 and 5 were bent inwards so that they formed an angle of about 850 towards the straight parts. The total length of the headband l was 16 cm. The ends of the headband were cast as continuous balls 7 and 9 with a diameter of 0.64 cm.

When the headband 1 was unloaded, the free distance between the balls 7 and 9 was about 5.7 cm. When the balls 7 and 9 were separated to a distance of 14.35 cm, the spring force was about 180 g.

The hearing protector according to the example was then mounted by inserting the balls 7 and 9 by hand into a cavity 30 on the earplugs 20. Test results with this hearing protector are shown in Example 4.

Example 2 Parts 22 and 28 of two plugs 20 having substantially the same shape and dimensions as described in Example 1 were made by die casting a plasticized polyvinyl chloride composition having the following ingredients: Ingredient Weight parts PVC plastic (viscosity 11, 11) 100 Plastolein 9775A plasticizer 65 di-n-octyl azalate 25 calcium zinc stabilizer (CZ-10) 2 2 silicone fluid (Dow 20O) 3 0.5 epoxidized soybean oil (G-szf * 12 1 manufactured by Emery Industries, Inc., Cincinnati, Ohio manufactured by Interstab Chemicals , Inc., New Brunswich, New Jersey manufactured by Dow Corning Corp., Midland Michigan 4 manufactured by Rohm and Haas, Philadelphia, Pennsylvania Shore The hardness value of the molten material was about 50. The volume 24 in the capsule 22 was filled with a plug of polyvinyl chloride foam of the same type as in Example 1. The capsules 22 were then glued to the bases 28 by means of a two-component polyurethane adhesive.

The headband 1 of this example is substantially the same in shape and size as that of Example 1. However, it was made by injection molding a polyacetal plastic (Delrin, manufactured by E. I. du Pont de Nemours and Co., Wilmington, Delaware). When the ends of the headband were separated to a distance of 1, 35 cm between the balls 7 and 9, the inward spring force became about 142 g.

The hearing protector was completed by hand mounting the plugs 20 to the headband 1 and tested according to the procedure of Example 4. Example 3 Parts 22 and 28 of a pair of plugs 20 were made by die casting of a heat treated silicone rubber, SWS-7655, made by SWS Silicones Corp., Adrian, Michigan. Curing in the form of the molded elements took place for about 10 minutes at a temperature of about 1770 ° C. The Shore A hardness value of the treated silicone rubber was about 50. The volumes 24 in the capsules 22 were filled with plugs of polyvinyl chloride foam of the same type and in the same manner as in Example 1. Thereafter, the capsules 22 were glued to the plinths 28 using room temperature hardening silicone rubber. The finished plugs 20, having substantially the same dimensions as those in Examples 1 and 2, were then mounted on a headband 1 of substantially the same dimensions and geometry as those in Examples 1 or 2.

However, the headband 1 was made by injection molding Celcon, a highly crystalline acetal polymer manufactured by Celanese Chemical Co., New York, N. Y. The headband 1 gave a spring force of about 174 g when the balls were separated at a distance of 14.35 cm.

The hearing protection was then tested according to the procedure of Example 4.

EXAMPLE 4 The hearing protectors in Examples 1 to 3 were subjected to a comparative test against each other and against a number of commercially available, known hearing protectors of substantially the same type. Audiometric data were obtained along with comments regarding convenience and ease of use from subjects. Three subjects were used in the tests, which were repeated three times for each hearing protector with each subject. The subjects were instructed to adjust the plugs in the best way to achieve the highest sound attenuation with each hearing protector.

The audiometric test followed ANSI S3.19 with the restriction that three instead of the prescribed ten subjects were used. The results of the audiometric tests are, for reasons of suitability, given in Table 1 as singular Noise Reduction Ratings (NRR). The conversion of ANSI S3.19 audiometric sample values to single NRR values is described in the monograph: "Single Number Measures of Hearing Protector Noise Reductions", Elliott H. Berger, EA-RLOG, EAR Corporation, Indianapolis, Indiana, 1979. It It should be noted that in each of the known hearing protectors, the earplugs were attached to the headband in a non-conductive manner.

Table l headband NRR hearing protection spring force (g) (dB) comment known (T) 80 ll seem to let through noise despite adjustment by hand known (W-10) 166 15 difficult to adjust known (W-20) 216 15 difficult to adjust known (MSB) 177 16 difficult to put on and adjust known (DSS) 248 14 very convenient example l 180 22 self-adjusting example 2 142 21 self-adjusting example 3 174 24 self-adjusting Example 5 Several hearing protectors are manufactured using the PVC headband li Example 1 and plugs 20 of the type made according to Example 3. In the present example, different filling materials 26 were used to fill the volume 24 in the capsule 22. The resulting hearing protectors were tested audiometrically on a single copy using test equipment 8006942 -Û and procedure according to ANSI S3.l9. The test results are given in the following Table 2.

Table 2 sound attenuation (decibels) at different frequencies (Hz) PIOPP 'filling f = 125 250 500 1000 2000 3150 4000 6300 8000 PVC ~ foam plug 28 28 28 30 32 36 36 38 4l high-speed polyurethane foam plug 28 26 27 27 26 40 46 45 43 slowly recurring polyurethane foam plug 25 26 29 30 29 40 39 41 41 glass wool 27 28 27 27 28 38 41 43 41 - silicone "silly Putty" 27 26 26 26 29 42 42 42 42 air 25 24 24 25 32 43 45 46 46 water 7 27 25 22 28 30 43 42 41 42 Although the invention in particular has been shown and described in the description with reference to suitable embodiments, the person skilled in the art will recognize that various changes in design and execution may occur. carried out without departing from the inventive concept.

Claims (10)

8006942-0 get Patent Claims Hearing protection comprising a substantially U-shaped, resilient headband (1), the opposite ends (3, 5) of which each support their inwardly directed means for contact with the ear canal, each means (20) having a first end part which is arranged to be pressed by the resilient headband to close the ear canal and a second opposite end portion whose outer dimensions are sufficiently small to be surrounded by the eardrum, which second end portion is directly connected to the respective opposite end of the headband, characterized by a) the first end portion of each means for contacting the auditory canal comprises a comic plug portion having a cone angle of between about 200 and 300, said plug portion having a closed inner end and an open outer end, the inner end of the plug portion having a size and shape adapted to be partially inserted into the ear, and wherein the inner end of the plug part has a smaller diameter than the outer end of the plug part and wherein at least the part of the plug part which can be pushed into the ear canal the gene comprises a softly resilient capsule (22) which is at least partially filled with a resilient or elastic filling material (26); b) that the second end portion of each means for contact with the ear canal comprises an end cap (28), which is attached to the plug portion, engages the plug portion and has a cavity (30) and a channel (32), which leading to the cavity, which channel has a chamfered surface which widens in the direction of the cavity, which cavity extends inside the open outer end of the plug part in such a way that the tendency of the means for contact with the ear canal to fold is reduced; c) that the opposite ends (3 or 5) of the headband (1) each have an inwardly directed segment with an end ball (7 or 9) at its end and d) that a joint connects the cavity of each lid with resp. end ball on the headband, whereby the means for contact with the auditory canal can swing around the joint point and can form to the ear under the pressure of the headband, each joint having a center point which is 8006942-0 / lf centrally located inside the end cap (28), which beveled surface (34) is a conical abutment surface for limiting the tilting of the contact means. Hearing protection according to claim 1, characterized in that the material in the plug has a Shore A hardness, determined according to ANSI ASTM D 2240-75, of between about 20 to about 50. Hearing protection according to Claim 1, characterized in that the volume of the plug is at least partially filled with a resilient or elastic filling material (24). Hearing protection according to Claim 3, characterized in that the filling material is an externally softened polyvinyl chloride foam, the nature and content of the plasticizer giving the foam the property of slowly regaining its shape in the event of deformation and low return pressure in the event of deformation. Hearing protection according to claim 1, characterized in that the volume in the plug is hermetically sealed and at least partially filled with liquid or gas. Hearing protection according to claim 1, characterized in that the plug is made of silicone rubber. 7. Hearing protection according to claim 1, characterized in that the plug is made of polyvinyl chloride. Hearing protection according to claim 1, characterized in that the inwardly directed spring force, generated by the headband at a difference of 14.35 cm between the opposite free ends, is between 1N and 2N. 9. '9. Hearing protection according to claim 1, characterized in that the headband is made of a rigid polyvinyl chloride. 10. Hearing protection according to claim 1, characterized in that the headband is made of polyacetal.