GB1066425A - Remote control for rock drill - Google Patents

Abstract

1,066,425. Percussive drills. GARDNERDENVER CO. Feb. 18, 1966 [March 17, 1965], No. 7282/66. Heading B4C. A control system for a pneumaticallyactuated rock drill 13 and feed motor 15 comprises a main valve 21 having a spool valve (53, Fig. 3, not shown), movable to a first position in which a supply port (73) communicates with a port (84) to effect a retracting movement of the drill along a mounting 14 and to a second position in which the supply port communicates with a port leading to the drill motor and a port (83) to effect a forward feed of the drill, an auxiliary valve 30 being provided to exhaust pressure applied to the spool valve in order to maintain it in its second position. In operation, with the valve spool (58) in its lowest position (Fig. 3, not shown) air is fed through the port (73) and port (84) to the feed motor 15 to retract the drill. Upon raising the spool against the action of a spring (68) by means of a handle (22), air flows from the port (73) to the drill 13 via a hose 24 and also, via a passage 95 in the spool, and the port (83) to the feed motor so as to effect a forward feed; a throttling groove (94) is formed in the surface of the spool so that by rotating the latter the rate of feed may be controlled. At the end of the forward feed stroke, the auxiliary valve 30 is actuated by means of an abutment 32 on the drill so as to exhaust the air below the spool thereby allowing it to drop to its initial position under the action of the spring; an alternative exhaust valve (101) is provided on the handle 22. If it is required to operate the drill and feed motor intermittently, such as for starting a hole, the spool is raised and rotated to bring a port (92) therein into line with the port (83) and then by slightly oscillating the spool the feed is intermittently controlled. At the same time, by raising and lowering the spool slightly, a pair of V-notches (93) provide a small flow of air to the drill motor.