Protective helmet of foamed polyurethane between two rigid shells - which are connected only by the plastic foam

摘要

Protective helmet is made of two parallel, independent, rigid shells between which polyurethane foam is injected directly. It is only the foam that connects the shells: the inner shell is of polyurethane (pref. reinforced with a glass-fibre mat or fabric). The outer shell is pref. of reinforced polyester, or alternatively of epoxy resin, which itself may be reinforced with a glass-fibre mat or fabric. The polyurethane foam is pref. about 12 mm. thick and of density ca. 60-70 g./dm3. The helmet has a known shock-absorbing lining, and inside that a material that rests kindly on the head.