The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 25, 1983
Filed:
May. 07, 1979
Applicant:
Inventors:
Pekka Salmi, Tampere, FI;
Aimo Helin, Tampere, FI;
Assignee:
Oy Tampella Ab, , FI;
Primary Examiner:
Int. Cl.
CPC ...
E21C / ;
U.S. Cl.
CPC ...
173-8 ;
Abstract
A hydraulic control system for use with a rock drill is adapted to sense a pressure build-up in the drill's rotation motor and in response thereto, to reverse the direction of feed of the feed motor as well as to supply hydraulic fluid to a shank cylinder on the rock drill. Supplying hydraulic fluid to the shank cylinder assists in freeing the drill from the rock.