Title:
HYDRAULICALLY OPERATED EARTH BORING TOOLS
United States Patent 3438450
Inventors:
Failing, Jay C.
Publication Date:
04/15/1969
Assignee:
FAILING IND INC
International Classes:
E21B7/02; E21B15/04; E21B7/02; E21B15/00; (IPC1-7): E21C11/02; E21C5/10; E21C9/00