GB1279111A - Improvements relating to rock drilling apparatuses and their operating cycles - Google Patents

Abstract

1279111 Rock drills GARDNER DENVER CO 23 June 1969 [20 March 1969] 31633/69 Heading B3C [Also in Divisions B4 and F2] A rock drilling apparatus comprises a drill 12 having a percussive motor 17, a fluid, e.g. air operated feed motor 18 for moving the drill along a support 10, the quantity of pressure fluid flowing to the percussive motor being reduced by a valve for collaring the drill hole, and a timing means ensuring that the reduced quantity of pressure fluid is fed to the motor for a predetermined time before the motor receives fluid at substantially normal supply pressure. The drill 12 further comprises a reversible rotary motor 14, which may also have fluid at reduced pressure fed to it. A drill steel 16 has a hollow bore for receiving flushing liquid. The illustrated drilling apparatus operates in the following manner. With the drill initially in the left-most position, i.e. with valve 58 depressed and in the b position, momentary manual actuation of START valve 72 enables air in supply conduit 22 to pass via conduits 64, 110 to move valve 26 to its b position, thus effecting feed of pressure air via conduit 22, valve 26, and adjustable throttle valve 32 to the rotary motor 14, which is rotated at a reduced speed. (The valve 26 is maintained in its b position after START valve 72 is released by virtue of air passing through restrictor 28.) Air further flows via valve 26, adjustable throttle valve 112 and conduits 111, 114 to operate the percussion motor 17 at reduced power. Simultaneously air passes via valve 26, an adjustable pressure regulator valve 48 (see Division F2) and a forward feed valve 52 to the feed motor 18. The regulator valve 48 ensures that the pressure of air supplied to the feed motor 18 is a proportion of the supply pressure in conduit 22. Air passing from valve 26 via conduit 116 moves valve 42 to the b position to effect supply of flushing water to the drill bore. Release of the START valve 72 will enable air to pass via conduit 110, valve 72 and an adjustable timing valve 92 to a reservoir 90. When the pressure in the reservoir has increased sufficiently DRILL valve 74 will be moved to its b position to effect supply of air via conduits 64, 124 to valve 36 so as to move the latter to its b position thus effecting supply of air at full supply pressure to the motors 14 and 17. The feed motor 18 is supplied with air via valve 36, a second adjustable pressure regulator valve 50 and forward feed valve 52. The valve 50 is similar to valve 48. The drill is fed along, operating at full power until a projection. 56 strikes actuator 54b thus moving the sensing valve 54 to its b position so as to permit pressure air to flow through an adjustable control valve 135 to a reservoir 137 which provide a time delay and to permit air to pass via conduits 134, 180, 138 to move valve 86 to its b position, so as to allow exhaust of air in conduit 140 thus enabling DRILL valve 74 to move to its a position. Valve 36 can now move to its a position to stop advance and drive of the drill. After the delay which permits through flushing of the drill hole, REVERSE valve 76 is moved to its b position by air from the reservoir so that air can then pass via conduits 64, 136, 138 to maintain valve 86 in its b position. The reverse supply valve 40, which is moved to its b position by air supplied via valve 76 and conduit 136 causes the feed motor 18 to reverse and retract the drill along the supprt. The flushing water is then exchanged for air to dry the drill bore, by the valve 42. Further the motors 14, 17 are operated at reduced power via adjustable valves 32, 112 to facilitate withdrawal of the drill bit. The cycle is completed when projection 60 contacts the actuator 58b. The valves 58, 54 are air-washed by air via conduits 108, 106. The valves 70, 74, 76, 84 may be manually operated to modify the operating cycle and the control circuits can be contained in compact enclosures 20, 62, e.g. formed from a number of plates (184), (186), (188), (190), (192), Fig. 3 (not shown) fastened together and having the conduits &c. machined into them. The apparatus may have only one pressure regulator valve.