| 摘要 |
<p>The invention relates to a safety helmet having a shell injected from thermoplastics, and the method for manufacturing the same. The helmet shell is of composite structure and includes a rigid insert of reinforced resin and an outer casing of injected thermoplastics molded onto the insert which is embedded within the mass of said outer casing and is prestressed by shoulders 5 and 6 provided on overlapping portions 3 and 4 of casing 2, after cooling of the same.</p> |
