GB1325240A - Portable rock drill - Google Patents

Abstract

1325240 Rock drills GARDNER-DENVER CO 1 Nov 1971 [4 May 1971] 50593/71 Heading B3C [Also in Divisions B4 and C3] In a rock drill, a drill support 42 is pivoted to a boom 18, a percussive drill 44 carrying a drill rod is movable on support 42 by a fluid motor 54, hydraulic pistons 48, 36 are adapted to pivot support 42, and control means 66 sense the position of the support and therefore of the drill rod, and actuate the pistons so as tomaintain the attitude of the drill rod in a required direction. Boom 18 is adapted to be pivoted about two axes 22, 24, on a frame 16, by hydraulic pistons 26, 28, and frame 16 is pivotally mounted on a crawler undercarriage 12. Control means 66, Fig. 4, comprises a spherical housing 68 pivotally mounted on a bracket 70 at 72, and bolted to support 42, and the pivoting movement is produced by an hydraulic cylinder 80 which is interconnected to an hydraulic cylinder 84. Pivotal movement of boom 18 will displace fluid from either end of cylinder 84 and such fluid will be forced into the corresponding end of cylinder 80 to produce an equal pivotal movement of housing 68. The cylinders 84, 80, are connected to a valve 94. Control means 66 also comprises four ball valves 114a 114b, 114c, 114d, Figs 7, 8, which are adapted to be closed by a pivotally mounted weight 116, operated by gravity, the weight being normally held against pivoting by a piston 130, actuated to release the weight by fluid pressure which enters a chamber 96 through the ball valves. The latter are connected to an air pressure supply 150, Figs. 9, 9A, and also to the ends of control valves 168, 170, these valves leading to hydraulic cylinders 36, 48. In operation, with control means 66 in the Fig. 3 position, if support 42 is swung out of the vertical, weight 116 will tilt to engage and close ball valve 114a, Fig. 9, thereby causing a pressure increase to conduit 144a, and valve 168 moves to position a. Fluid pressure is supplied to the rod end of cylinder 48 causing support 42 to move about pivot 46 into the vertical position, whereupon the gravitational force on weight 116 causes it to resume the Fig. 7 position with the valve 168 moving to the position c. In a similar manner, if the support 42 is pivoted about axis 38, Fig. 9, the control means would operate cylinder 36 to move the support back to the vertical position. The alignment of control means 66 with the centre line 108, Fig. 8, when boom 18 is pivoted about axis 22, Fig. 1A, is maintained by the circuit including cylinders 80, 84, Fig. 4. The control valves can be actuated manually when initially setting the axis of the drill rod.