Title:
Safety lock for extensible masts
United States Patent 2508835


Inventors:
James, Moon
Shaw, John F.
Application Number:
US67703146A
Publication Date:
05/23/1950
Filing Date:
06/15/1946
Assignee:
WESTERN OIL TOOL & ENGINEERING
Primary Class:
Other Classes:
52/118, 254/104
International Classes:
B66C23/20; E06C5/42
View Patent Images:
US Patent References:
2331558Portable derrick1943-10-12
2204713Portable derrick1940-06-18
1644613Extension tower1927-10-04
1260216N/A1918-03-19
0837253N/A1906-11-27
0740942N/A1903-10-06
0293851N/A1884-02-19