METHOD OF AND DEVICE FOR ADJUSTING THE FEED MOVEMENT OF A DRILL ROD FOR DRILLING A ROCK

摘要

A B S T R A C TA method of adjusting the feed movement ofa drill rod for drilling a rock by rotating the drillrod by means of a pressure medium operated rotarymotor and by feeding the drill rod in a drillingdirection and in the opposite direction by means ofa pressure medium operated feed motor. A pressurechange acting on the pressure side of the rotarymotor due to a change in the rotation resistance ofthe rotary motor is caused to act on the outletside in order to reverse the feed force of the feedmotor in dependence of the pressure change. Thepressures on the pressure side and the outlet sideof the feed motor are controlled so that, when thepressure on one side increases because of the pressurechange, the pressure on the other side decreasesand vice versa. In a device for carrying out themethod, the pressure medium circuit is provided withmeans which control the pressures on the pressureside and the outlet side of the feed motor so that,when the pressure on one side increases, the pressureon the other side decreases and vice versa.