3880157 is referenced by 12 patents and cites 4 patents.

A diving helmet assembly consisting of a transparent plastic helmet having an outwardly extending flange, and a hollow plastic collar which fits around the helmet and engages the flange. The helmet is substantially dome shaped preferably with flat polished portions for clear viewing, and has a hose connection to permit air to be supplied to the helmet when it is immersed in water. The hollow interior of the collar is filled by the user with heavy ballast material such as sand or concrete to counteract the buoyancy of the air filled helmet in water.

Title
Diving helmet assembly
Application Number
05/434,363
Publication Number
3880157
Application Date
January 17, 1974
Publication Date
April 29, 1975
Inventor
Elifritz C James
Agent
Engstrom Harry C
Winter John M
Long Theodore J
IPC
A62b 18/04
B63C 11/02
B63C 11/06
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