| 摘要 |
A sound-attenuating impact-absorbing earcup comprises a shell having a plurality of generally circular recesses adjacent to the periphery of the cup which function as stiffening contours. The stiffening contours increase the effective stiffness of the earcup shell, improving its sound attenuating capability, and also concentrate applied stress onto those portions of the stiffening contours nearest the point of applied stress. Sufficient applied force causes the shell to fracture in the areas of the stress concentrators, thereby to absorb impact energy in a controlled manner without transmitting it to the head of the wearer. To further enhance its sound-attenuating and impact-absorbing capabilities, the earcup is formed of a low-tensile-strength, high-elongation, high-loss-factor material such as polyvinyl chloride or similar polymer.
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