| 摘要 |
<p>An energy-absorbing sound-attenuating earcup (10) comprises a rigid shell (12) of an ABS terpolymer that is about 0.090 inch thick so as to crush upon impact at an applied force less than that required to crush the skull of the wearer. The shell (12) has an inner coating (60) of a sound-deadening rubber material to compensate for the reduced sound-attenuating capability of the thinner-than-normal shell (12). Spaced flanges defining a peripheral channel for receiving a cord (32) of a helmet suspension (34) are formed as staggered series of (16,18,20,22,24,26,28,30) tabs rather than as circumferentially continuous members to facilitate crushing of the shell (12) upon impact. Resilient earseals (62) disposed between the shells and the wearer's ears comprise first thicknesses (66) of standard polyurethane foam and second thicknesses (64) of slow-recovery polyurethane foam to provide additional impact absorption while permitting the earseals (62) to conform to the wearer's head in cold weather when the helmet is first put on. The earcup (10) may alternatively be releasably secured to the helmet by means of mating hook and loop fastener strips (36) rather than being secured through the staggered tabs.</p> |
