Acoustical earmuff
First Claim
1. An acoustical earmuff device comprising a pair of earmuffs fastened to opposite ends of a generally U-shaped connecting band, the earmuff comprising a rigid cup section connected to the band on one side of the cup, and a compliant foam section on the other side of the cup for contact with the wearer, wherein the improvement comprises, using as the foam section a foam material having a low static stiffness, and a high dynamic stiffness, resulting in an earmuff with higher attenuation;
- wherein said foam material has a dynamic spring constant of at least 300 pounds/inch and a dynamic material loss factor of at least 0.25.
15 Assignments
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Accused Products
Abstract
An earmuff cushion providing improved attenuation is described. The cushion is a foam material having a low static stiffness, and a high dynamic stiffness, which produces improved attenuation in the earmuff in which it is used. Earmuffs made from the cushion and improved methods of making the cushion and the earmuffs are also described.
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Citations
17 Claims
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1. An acoustical earmuff device comprising a pair of earmuffs fastened to opposite ends of a generally U-shaped connecting band, the earmuff comprising a rigid cup section connected to the band on one side of the cup, and a compliant foam section on the other side of the cup for contact with the wearer, wherein the improvement comprises, using as the foam section a foam material having a low static stiffness, and a high dynamic stiffness, resulting in an earmuff with higher attenuation;
wherein said foam material has a dynamic spring constant of at least 300 pounds/inch and a dynamic material loss factor of at least 0.25. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A one piece molded foam earmuff cushion for noise exclusion having a low static stiffness, and a high dynamic stiffness, resulting in higher attenuation when used in an earmuff;
wherein said foam earmuff cushion has a dynamic spring constant of at least 300 pounds/inch and a dynamic material loss factor of at least 0.25. - View Dependent Claims (12, 13, 14, 15, 16, 17)
Specification