GB1056369A - Improvements in automatic rock drilling means - Google Patents

Abstract

1,056,369. Drilling. ATLAS COPCO A.B. Oct. 12, 1965 [Oct. 14, 1964], No. 43208/65. Heading B3C. [Also in Division B4] An automatic rotary-percussive rock drilling machine comprises a rock drill 10 mounted on a slide 11 which is movable forward and backwards along a shell 12 by means of a reversible feed motor 18, a limit switch 71 being mounted on the forward end of the shell so that when operated by the rock drill a reversing valve 60 is actuated via a circuit 70, 77, 78 and servomotor 60a thereby causing the rock drill to return to its rearward position. The reversible motor is compressed-air operated and connected via feed lines 54, 55 to a control valve 51 communicating with a main feed line 39 which is connected via a diaphragm actuated valve 32 with the pressure source. A second control valve 40 is connected via a passage 36 and a line 42 with the rock drill. A third control valve 44 is provided for controlling flushing water through a line 48, a servo-operated valve 50, line 49 and a bore 22 in the drill bit 15. In operation, with the rock-drill in its rearward position so that an abutment 76 on the slide is actuating a rear limit-switch 72, a manually-actuated valve 87 is operated so as to admit air to open the diaphragm-controlled valve 31 thereby allowing the air to flow via the valves 40 and 51 to actuate the rock-drill and the feed motor respectively, water is also fed to the drill bit via valves 44, 50. The slide then moves forward on its drilling stroke allowing the rear limit switch to move to its alternative position and thereby, via lines 85, 89, maintain the diaphragm valve open. At the completion of the drilling stroke, the forward limit switch 71 is operated which then, via the servo-circuit 70, 77, 78 actuates the reversing valve so that the feed motor reverses the drill slide. Simultaneously, the air for operating the rock drill is throttled via a plunger 80 in the valve 40 and the reversal of the pressure to the feed motor causes actuation of a second servo-circuit 81, 84 so that the delivery of flushing water is replaced by flushing air via a conduit 47. The rock drill returns to its rear position thereby actuating the rear limit switch so that the air to the diaphragm valve is exhausted and so allows the latter to close. In a modification, Fig. 11 (not shown) the rear limit switch is dispensed with and replaced by a shuttle valve 105 for controlling the reversing valve 60 and the throttle plunger 80. A further valve 100 is provided for controlling air fed to a motor 104 for rotating the drill bit. The pneumatic controlling circuits may be replaced by hydraulic or electric circuits.