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:
May. 17, 1977
Filed:
Jun. 18, 1975
Pekka Salmi, Tampere, SF;
Rolf Strom, Tampere, SF;
Oy Tampella AB, Tampere, SF;
Abstract
A hydraulic drill, more particularly a rock drill, having a self-adaptive servo control system comprising three separate but interdependent hydraulic circuits, one for operating and controlling the drill rotation motor, one for controlling and operating the drill impact unit and a third for operating and controlling the drill feed motor. Control valves are disposed in each hydraulic circuit and are automatically operated such that when the pressure in the rotation motor circuit increases beyond a predetermined limit, the pressure in the impact unit circuit is decreased so as to decrease the power of the impact unit, and when the pressure in the rotation motor circuit decreases below a predetermined limit, the pressure in the impact unit circuit is decreased so as to decrease the power of the impact unit, and also comprising a differential pressure valve in the feed motor circuit which controls the operation of the feed motor such that when the impact power is decreased, the feed is also decreased, and vice versa.