| 摘要 |
A hydraulic drilling outfit has a hydraulically driven hammer drill which is fastened pivotally to a hydraulic thrust unit. A control for the hydraulics utilizes the flushing water for the drill bit as the power-source for all of the motions executed by the drilling outfit. One hydraulic supply line to the control of the thrust unit and one line from the control to the hammer drill are sufficient for operating the system in an open circuit. A rotary slide valve simultaneously controls the thrust and withdrawal motions as well as the operational states of drilling and not drilling. The desired value adjustment for the speed of thrust is arranged on the rotary slide valve. |
