Patent GB-190722636-A (GB)
Title: Improvements in Rock-drilling Machines.
Inventor: GROSE JAMES EDWARD HOSKINS
Filed: 1907-10-14
Granted: 1908-07-16
Abstract: 22,636. Grose, J. E. H. Oct. 14. Rock drills.-In a rock drillof the piston-hammer type in which the piston controls the distribution of the actuating - fluid, means are provided whereby the actuating- fluid feeds the power cylinder forward, a jet of the actuating-fluid being used to convey water through the tool to remove detritus from the bottom of the hole being drilled. The operating- fluid is conveyed through the opening 12 to a casing 1 in which the power cylinder is mounted to slide longitudinally within limits. The power cylinder consists of an outer tube 2 securely connected to an inner tube 3. The back guide-tube 6 is provided with a pin 7 to receive a handle for rotating the device. A tube 17 acts as a compression chamber to cushion the back stroke of the piston. An annular piece 27 forms a seat and stop for an annular valve 26. The tool-holder 32, which receives the blows of the piston 15, has a flange 34 with slots into which pins 35 project, so that the tool-holder 32 is movable longitudinally within limits but rotates with the front head 28. The front head 28 fixed to the cylinder 2 has a hollow flange 29 with forwardly-directed holes 30, through which the exhaust escapes, to keep the sludge from the operator. A resilient buffer 38 takes the blow of the hammer when the tool 33 is not in position to receive it. The tool 33 abuts against a hard steel cylinder 40. A nozzle 45 with a strainer 46 directs a jet of actuating-fluid so as to draw water through a tube 57, strainer 58, water ring 54, and duct 49 directing it through the hollow tool 33. The ring 54 is kept against its seat on the head 28 by a helical spting 61. Any actuating-fluid leaking between the tool-holder 32 and bushing 23 escapes by a hole 73a. Longitudinal supply ports 73, 74 communicate with the casing 1 through ports 75,76, and have a number of ports 105 communicating with the recess 104 of the piston 15 throughout the stroke. Smaller longitudinal ports 77, 78 convey actuating-fluid to the annular space 25 in front of the valve 26,so that actuating-fluid at initial pressure is continuously acting on the front of the valve, which is of less area than the rear end. Actuating- fluid passes from the space 25 through an opening 67 to the nozzle 45. When the piston 15 is in its rearmost position, actuating-fluid passes from the recess 104 through ports 16, 97, 98, 95, 96, 99, 100 to the back of the piston to impel it on its forward stroke, the front of the cylinder being open to exhaust through ports 84, 85, 82, 82<a>, 83, 83a, flange 29, and holes 30. When the ports 84, 85 are closed by the piston 15, the forward end of the cylinder is still open to exhaust through ports 80 in the valve 26, and ports 81 communicating with the exhaust ports 82, 82<a>. Just before the piston 15 strikes the tool-holder 32, the rear end of the cylinder is open to exhaust through ports 86, 87, 82, 82<a>. At the same time, actuating-fluid passes to the front of the piston from the recess 104 through ports 93. 94, 89, 90, 91, 92 and recess 88, moving the valve 26 so as to close the ports 80, the piston itself closing the exhaust ports 84, 85, 101, 102. When the piston 15 has passed the ports 84, 85, the ports 101, 102 serve to relieve the pressure in the ports 89, 90 to allow the valve 26 to move back on to its seating 27.