GB190401340A - Improvements in and relating to Rock Drills or the like. - Google Patents

Abstract

1340. Walton, C., and Rayner, G. H. Jan. 19. Rock drills, percussive. In a rock drill worked by compressed air, the distributing - valve is air driven and the air ports are so arranged as to prevent the valve from chattering. Compressed air enters the valve-chest f<1> through an inlet a and ports b, c, d, e, and at the begining of the outward stroke of the piston k the ports b, d, e are cut off from communication with the cylinder i by means of the distributing-valve f, the only communication being through the port c round the valve f and through a port g. The forward end of the cylinder i is open to exhaust through a port h and the air in the valve-chest f<1> supplied through the port b exerts pressure against the back of the valve f, and holds it in position, the forward end of the valvechest f<1> being in communication with the exhaust through a passage l which leads to the interior of the cylinder and is in communication with the exhaust. During its forward stroke the piston k, which is formed with an annular groove k<1> round its middle, covers the passage l and uncovers a similar passage m, thereby throwing over the valve f in position for the reverse stroke of the piston. Instead of employing the ports b, e, passages n, o may be formed through the valve itself.