Title:
Protector for drill pipes
United States Patent 2308147
Inventors:
Ballagh, James C.
Publication Date:
01/12/1943
Export Citation:
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Assignee:
PATTERSON BALLAGH CORP
Primary Class:
175/325.5
Other Classes:
138/110, 138/118
International Classes:
E21B17/10; E21B17/00
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