05309576 is referenced by 43 patents and cites 16 patents.

A protective helmet having a dome-shaped body and air vent structure in the body comprising a body consisting of molded, synthetic resin sections, a first the section having relatively higher density and a second the section having relatively lower density; the first section extending in strengthening adjacency to the second section, laterally of the vent structure.

Title
Multiple density helmet body compositions to strengthen helmet
Application Number
7/717485
Publication Number
5309576
Application Date
June 19, 1991
Publication Date
May 10, 1994
Inventor
Lester V Broersma
Bellflower
CA, US
Agent
William W Haefliger
Assignee
Bell Helmets
CA, US
IPC
A42B 3/02
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