Hearing protection cap
View Patent ↗The present invention relates to an ear cap intended for use as hearing, the ear cap having a sound-reflecting outer shell and a liner of sound absorption materials. The ear cap is characterized by at least one sound-reflecting and vibration-damping weight element arranged on or within the sound absorption liner to at least partly block an audio mode of vibration that would have existed in the cap in the absence of the weight element.
1. A hearing protection cap set, each cap comprising:
a shell member having an inner surface and an opposite exterior surface;
an inner layer comprising a flexible hidden layer disposed against the inner surface of the shell member, and a flexible facing layer having an ear-facing surface and an opposite attachment surface, the attachment surface disposed against the hidden layer; and
a weight element positioned between the facing layer and the hidden layer,
wherein the shell member defines a footprint having a footprint area, and the weight element defines an area that is at least 50 percent less than the footprint area.
2. The hearing protection cap set of claim 1 wherein the shell member forms a cavity defined by the inner surface.
3. The hearing protection cap set of claim 1 wherein the hidden layer is a first sound absorbing material.
4. The hearing protection cap set of claim 3 wherein the facing layer is a second sound absorbing material, which may be made of a material similar or different than the first sound absorbing layer.
5. The hearing protection cap set of claim 4 wherein the first sound absorbing layer and the second sound absorbing layer are of an identical material.
6. The hearing protection cap set of claim 1 wherein the facing layer and the hidden layer are each made of a foam sound absorbing material.
7. The hearing protection cap set of claim 1 wherein the weight element comprises a polymer having a first specific gravity, wherein the polymer is impregnated with a material having a second specific gravity that is greater than the first specific gravity.
8. The hearing protection cap set of claim 7 , wherein the weight element comprises a composite sheet of vinyl and lead.
9. The hearing protection cap set of claim 1 wherein the shell defines a footprint having a footprint area, and the weight element defines an area that is at least 75 percent less than the footprint area.
10. A hearing protection cap comprising:
a shell member having an inner surface defining a cavity and an opposite exterior surface;
a hidden layer disposed within the shell member cavity against the inner surface of the shell member;
a facing layer having an ear-facing surface and an opposite attachment surface, the attachment surface disposed within the shell member cavity against the hidden layer; and
a flexible weight element positioned between the facing layer and the hidden layer,
wherein the shell member defines a footprint having a footprint area, and the weight element defines an area that is at least 50 percent less than the footprint area.
11. The hearing protection cap of claim 10 wherein the flexible weight element comprises a polymer and a metal.
12. The hearing protection cap of claim 11 wherein the metal comprises lead.
13. The hearing protection cap of claim 10 wherein the hidden layer and the facing layer comprise an identical material.
14. The hearing protection cap of claim 10 wherein the weight element is adhesively attached to the hidden layer, the facing layer, or both.
15. A method of improving the sound attenuation of a hearing protection cap comprising a cap shell having an inner surface defining a cavity, the method comprising the steps of:
lining the cavity with an inner layer of sound absorption material;
co-extruding a polymer and a metal into a sheet;
forming a weigh element from the sheet;
sizing the weight element so that it has an area that is less than an area defined by the inner layer; and
attaching the weight element to an ear-facing surface of the inner layer.
16. The method of claim 15 comprises the step of positioning a second layer over the inner layer and the weight element.
17. The method of claim 15 further comprising the step of positioning the weight element on the inner layer such that it coincides with a cap antinode.