| 摘要 |
1,007,903. Boring earth &c. INGERSOLLRAND CO. July 2, 1964 [July 15, 1963], No. 27319/64. Heading E1F. A "down-the-hole" percussive drill is mounted on a spindle 23 rotatable in a head 11 which is moved by a fluid pressure motor 16 down a drill rig for feeding the drill, the spindle being slidable within a spindle driver 22 and forming with the driver a chamber 31 for pressure fluid and valve means 27, 35 for controlling flow of the fluid from the chamber to the motor in accendance with the longitudinal position of the spindle relative the driver. During automatic feed of the drill, air from a compressor passes through lines 51, 50 to a motor (not shown) rotating the driver in the head, the motor having a pinion 20 engaging a gear 21 on the driver which has splines 25 engaging splines 24 on the spindle. Air from a bypass line 50A flows into the chamber 31, and, with the spindle and driver positioned as shown, passes through the spindle bore 33 to drive the drill. When soft earth is encountered by the drill the spindle moves downwardly relative to the driver to bring the piston 27 below the port 35 so that air flows from the chamber into the line 44 to drive the motor 16 which drives a chain to force the head and drill downwardly. When the feed causes the piston to close the port there is sufficient residual pressure in the passages to bring the parts back to the position shown. The motor 16 may be operated under manual control, a valve 52 being set to direct air from the line 51 into the lines 58 or 59 depending on whether the head and drill are being raised or lowered. |
