WO2005072668A1

WO2005072668A1 - High attenuating earmuff device

Info

Publication number: WO2005072668A1
Application number: PCT/US2005/002159
Authority: WO
Inventors: Elliott Berger; Bjorn Jakobson
Original assignee: Cabot Safety Intermediate Corporation
Priority date: 2004-01-23
Filing date: 2005-01-24
Publication date: 2005-08-11
Also published as: US20050283882A1; BRPI0506978A; AU2005209264A1; RU2006130376A; CN1909862A; CA2552653A1; NO20062893L; EP1706082A1

Abstract

An earmuff device is provided, including a connecting band having opposing first and second ends, a pair of earmuff cup assemblies connected to the opposing first and second ends of the connecting band, a first foam disposed at the earmuff cup assemblies, and a second foam disposed at the earmuff cup assemblies, where the first foam comprises a moderately high density foam having highly engineered polymer transition properties with precise loss factor values, modulus values, and polymer transition values and maximum damping at prescribed temperature and frequency conditions, and where the second foam comprises a rnoderately high density hydrophilic foam particularly employed for optimal property convergence in cell size, air flow, density, and static stiffness. An earmuff cup, an earmuff cushion, and an earrnuff liner including the respective first and/or second foams, are also provided.

Description

HIGH ATTENUATING EARMUFF DEVICE

BACKGROUND OF THE INVENTION

1. Field of the Invention:

[0001] This invention relates generally to acoustic hearing protective devices and, more particularly, to an earmuff device comprising foam materials for providing a wearer with a high sound attenuation.

2. Brief Discussion of the Prior Art:

[0002] Earmuff devices are commonly used to protect against hearing damage in environments where noise levels are not able to be controlled within safe limits. Such devices generally include a pair of rigid cups connected by a head band, each cup having an interior lined with an acoustical material and a cushion extending from the cup toward the head of a wearer to seal the respective cup to the wearer's head around the ear.

[0003] Such, earmuff devices are recognized as having certain advantages over other forms of hearing protection devices, such as earplugs. For example, earmuffs are preferred for intermittent use where continuous insertion and removal of earplugs would be annoying or impractical. Additionally, earmuffs provide superior comfort properties over earplugs and other hearing protection devices particularly due to the soft cushion which contacts the head of a wearer and due to the absence of items inserted into the ear.

[0004] As with other hearing protection devices, maximum sound attenuating capabilities are desired for earmuffs in order to provide the necessary protection against sound exposure. In certain environments, such as at extremely loud industrial or manufacturing plants, at construction or demolition sites, etc., a very high sound attenuation is desired from earmuff devices. Thus far, however, an earmuff has not been achieved which can provided a suitably high sound attenuation while still providing the comfort and practicability features so desired by the wearer.

[0005] Many attempts have been made at increasing the sound attenuation of known earmuffs. These attempts have included reducing acoustic leaks through or around muff cups, increasing the mass and/or volume of the cups, increasing head band tension to tighten the fit of the muff cups on the head of a wearer, minimizing resonating surfaces such as flat surfaces, etc. While these attempts may have resulted in increases in attenuation, the resulting earmuff is often found to be bulkier, heavier, more difficult to put on, and generally less comfortable than typical earmuff assemblies.

[0006] Thus, an earmuff is desired which provides a high level of sound attenuation but is comfortable when worn, practical to use, and simple and economical to manufacture.

SUMMARY OF THE INVENTION

[0007] An earmuff device is provided, including a connecting band having opposing first and second ends, a pair of earmuff cup assemblies connected to the opposing first and second ends of the connecting band, a first foam disposed at the earmuff cup assemblies, and a second foam disposed at the earmuff cup assemblies, where the first foam comprises a moderately high density foam having highly engineered polymer transition properties with precise loss factor values, modulus values, and polymer transition values and maximum damping at prescribed temperature and frequency conditions, and where the second foam comprises a moderately high density hydrophilic foam particularly employed for optimal property convergence in cell size, air flow, density, and static stiffness. An earmuff cup, an earmuff cushion, and an earmuff liner including the respective first and/or second foams, are also provided. [0008] The above-discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:

[0010] FIGURE 1 is a front elevational view of a earmuff assembly of the invention; and

[0011] FIGURE 2 is a perspective view of an earmuff cup of FIGURE 1.

DETAILED DESCRIPTION OF THE INVENTION

[0012] An earmuff device 10 is shown in FIGURES 1 and 2 in an exemplary embodiment of the invention. The earmuff device 10 broadly comprises a generally U-shaped, resilient connecting band 12 and a pair of earmuff cup assemblies 14 and 16 connected to opposite ends of ' connecting band 12.

[0013] The ear muff cup assemblies 14 and 16 are affixed to the connecting band 12 in any desired manner. Most preferably, earmuff cup assemblies 14 and 16 may be connected to an adapter which, in turn, is connected to the band 12. The adapter may be configured to allow the ear muff cup assemblies 14 and 16 to pivot or rotate relative the band 12 or, alternatively, the adapter may hold the assemblies 14 and 16 fixedly on the band 12, etc.

[0014] Each of the earmuff cup assemblies 14 and 16 comprises a rigid earmuff cup 18, a cushion 20, and an earmuff cup liner 22. Rigid cup 18 is generally formed of two pieces, a cup shaped portion 24 and a cushion seal plate 26, which are fixed together at an interface, for example, by sonic welding, etc. The cushion 20 is fixed to the cushion seal plate 26 and extends from the rigid earmuff cup 18. The earmuff liner 22 is disposed at an interior of the rigid earmuff cup 18. The cushion 20 and earmuff cup liner 22 are shaped as desired to appropriately fit on the rigid earmuff cup 18 and to provide adequate fit and comfort to the wearer. For example, the cushion 20 and the liner 22 may be substantial round in shape or square, etc.

[0015] The earmuff device 10 is intended to be applied over the head of a wearer with the ear muff cup assemblies 14 and 16 fitted over the ears so that the ears extend entirely into the interior of the rigid earmuff cups 18 and the cushions 20 seal around the ears. The resilient connecting band 12 is worn around the head to hold the earmuff device 10 thereon. For example, the band 12 may extend over the crown or around the back of the head, or under the chin, etc. Further, the connecting band 12 possesses a tension which fits the ear muff cup assemblies 14 and 16 tightly, but comfortably over the ears.

[0016] When the earmuff device 10 is properly worn as described, the ear muff cup assemblies 14 and 16 effectively seal the ears from the outer environment. That is, the earmuff cup assemblies 14 and 16 act as a barrier between the inner ear of the wearer and sounds emanating in the outer environment. In particular, the cushions 20 and the earmuff cup liner 22 attenuate the passage of sound from the outer environment into the ears.

[0017] The cushions 20 and the earmuff cup liner 22 are formed any material(s) sufficient to provide high sound attenuation to the wearer. In a preferred embodiment, materials are used to compose the cushions 20 and the earmuff cup liner 22 such that the earmuff device 10 provides a sound attenuation having a Noise Reduction Rating (hereinafter, "NRR") of 30db or greater.

[0018] In a preferred embodiment, the cushion 20 comprises a moderately high density foam having highly engineered polymer transition properties with precise loss factor values, modulus values, and polymer transition values and maximum damping at prescribed temperature and frequency conditions. For example, the cushion 20 may be composed of a urethane foam having the above-mentioned properties, such as a foam available under the trade name, CONFOR. The foam of the cushion 20 may be of a homogenous construction or may be formed as laminate sheets adhered together to form the cushion 20. The cushion 20 may further include an outer liner of a vinyl material, etc., essentially covering the inner urethane foam.

[0019] The shape of cushion 20 may be cylindrical, round, or rectangular to fit the generally matching earmuff cup 14 and 16 design in a reasonable manner. Cushion 20 is quite flexible and may also be made to a shape requiring deformation to fit earmuff cup assemblies 14 and 16. Cushion 20 defines a central opening 21 which generally has a shape which matches the shape of cushion 20. Opening 21 is generally aligned with the internal portions of an ear such that the ear may be received within the rigid earmuff cup 18, as described above. An exemplary cushion 20 is disclosed in commonly assigned U.S. Patent No. 5,420,381 to Gardner Jr. et al., which is hereby incorporated in its entirety.

[0020] The earmuff cup liner 22 generally comprises an open cell foam or other material containing open pores of size and shape sufficient to absorb sound and provide high attenuation, as discussed above. The earmuff cup liner 22 is preferably formed of a moderately high density hydrophilic foam which is particularly employed for optimal property convergence in cell size, air flow, density, and static stiffness. For example, the liner 22 may be composed of a relatively soft urethane foam possessing the above-mentioned properties, such as a urethane foam currently produced by Lendell Manufacturing, Inc (LMI).

[0021] The invention, as set forth in exemplary embodiments herein, provides an earmuff device which is lightweight and comfortable when worn and which provides a high sound attenuation, preferably, an attenuation having an NRR of 30 or more. More particularly, the earmuff device of the invention comprises acoustic foams specifically designed and utilized to provided the wearer with this high sound attenuation, while maintaining comfort and practicality properties of the earmuff device.

[0022] While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

[0023] What is claimed is:

Claims

1. An earmuff device, comprising: a connecting band having opposing first and second ends; a pair of earmuff cup assemblies connected to the opposing first and second ends of the connecting band; a first foam disposed at the earmuff cup assemblies; and a second foam disposed at the earmuff cup assemblies; wherein the first foam comprises a moderately high density foam having highly engineered polymer transition properties with precise loss factor values, modulus values, and polymer transition values and maximum damping at prescribed temperature and frequency conditions; and wherein the second foam comprises a moderately high density hydrophilic foam particularly employed for optimal property convergence in cell size, air flow, density, and static stiffness.

2. The earmuff device of claim 1, wherein the pair of earmuff cup assemblies each comprise a cushion for contacting the wearer, the cushion comprising the first foam.

3. The earmuff device of claim 1 , wherein the pair of earmuff cup assemblies each comprise a liner disposed at an interior thereof, the liner comprising the second foam.

4. A cushion for an earmuff assembly, comprising: a moderately high density foam having highly engineered polymer transition properties with precise loss factor values, modulus values, and polymer transition values and maximum damping at prescribed temperature and frequency conditions.

5. A liner for an earmuff cup, comprising: a moderately high density hydrophilic foam particularly employed for optimal property convergence in cell size, air flow, density, and static stiffness.

6. An earmuff cup, comprising: a body portion; a cushion extending from the body portion for contacting a wearer; and a liner disposed at an interior of the body portion; a first foam disposed at the cushion, the first foam comprising a moderately high density foam having highly engineered polymer transition properties with precise loss factor values, modulus values, and polymer transition values and maximum damping at prescribed temperature and frequency conditions; and a second foam disposed at the liner, the second foam comprising a moderately high density hydrophilic foam particularly employed for optimal property convergence in cell size, air flow, density, and static stiffness.