GB748056A - Combination air and water valve for rock drills - Google Patents

Abstract

748,056. Percussive drills. CHICAGO PNEUMATIC TOOL, CO. March 29, 1954 [April 20, 1953], No. 9113/54. Class 124 A pneumatic percussive drill having a water supply tube passing through the ,piston and delivering water to a hollow steel is provided in the backhead with a single valve controlling the supply of water and of air to the piston, the arrangement of the valve being such that water is supplied to the steel before air is admitted to start the percussive action. As shown a drill has a water tube 60 leading from the back head 39, through a bore 62 in the piston 34 to a hollow steel 27. A valve in the back head comprises an air chamber 65 having at one end a connection 69 to a supply of compressed air and at the other a smaller diameter chamber 78 and a valve element 74 slidable in the chamber 78. A spring 80 in the chamber 65 urges the valve element into the closed position. A bush 88 having external grooves 89, 90 with radial holes 92 and 93 is fitted in the chamber 78 and a reduced portion 94 of the valve element 74 is slidable within this bushing. An annular recess 95 is provided in the reduced portion 94 wide enough to bridge the spaced radial holes 92, 93 and having seals 99, 100 at one end and a seal 102 at the other end of the recess. A small movement of the spindle 81 against the spring 80 moves the seal 100 into a position that the holes 92, 93 are both in communication with the recess 95 and water may flow to the drill steel, and further movement admits air to the piston valve, the water being therefore supplied to the steel before percussive action begins. The movement of the valve is controlled by a lever on a handle of the drill. The steel may be rotated by rifle bars and ratchet and means are provided for supplying a metered amount of lubricating oil to the operating air. The main air valve is constructed in such manner that live air may be blown through the water tube.