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:
Sep. 14, 1976
Filed:
Mar. 17, 1975
Applicant:
Inventors:
Pekka Salmi, Tampere, SF;
Rolf Strom, Tampere, SF;
Assignee:
Oy Tampella AB, Tampere, SF;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21C / ;
U.S. Cl.
CPC ...
173-8 ; 173108 ;
Abstract
A hydraulic rock drill having a hydraulic drill drive motor, a hydraulic feed motor, and a hydraulic impact unit and associated pumps for supplying hydraulic fluid under pressure and provided with an automatic control system including a valve controlling the flow to the impact unit under the dependence of the pressure in the rotation motor circuit such as to reduce the power of the impact unit when the pressure in the drive motor circuit exceeds a permissible pressure and vice versa. Additionally, the hydraulic system preferably includes an additional flow control valve such as to decrease the feed power when the impact power increases.