| 摘要 |
<p>Composite motor cyclist's helmet comprises an outer part consisting of a rigid upper cap obtd. by injection of polycarbonate or ABS or moulding of laminated polyester, and a semi-rigid lower shell of soft PVC or injection-moulded thermplastic polyurethane, held together by adhesion and/or riveting or fasteners. The shock-absorbing helmet lining comprises a rigid upper cushion made of e.g. expanded polystyrene with a density of 15-20 g/dm3 or semi-rigid expanded polyurethane with a density of 30-120 g/dm3, of hemispherical shape and a ring-shaped lower cushion or semi-rigid foam e.g. polyurethane. Pref. a trimming piece made from a flexible foam panel adhered to a fabric is fixed to the lower cushion by adhesion and also to the bottom of the upper cushion.</p> |
