GB375204A - Fluid pressure hammer - Google Patents

Abstract

375,204. Valve-gear for percussive tools. CHICAGO PNEUMATIC TOOL CO., 6, East 44th Street, New York, U.S.A. -(Assignees of Stevens, E. W. ; 6201, 2nd Boulevard, Detroit, Michigan, U.S.A.) Dec. 14, 1931, No. 34632. Convention date, Jan. 12, 1931. [Class 122 (ii).] In fluid-pressure actuated percussive tools wherein a simple ring lift valve 9 is mounted directly on the cylinder or on a closure member thereof as described in Specification 358,398 and moves transversely of the cylinder and engages seats thereon to control the admission to the two ends of the cylinder, the exhaust being controlled by the piston over-running ports in the cylinder wall, the seats of the valve are elongated so that the valve can move longitudinally as well as radially. The fluid pressure automatically centres the valve longitudinally and passes over both edges to the cylinder. The reduced portion 7a of the cylinder engaged by the valve is further reduced eccentrically to provide seats 15, 16 which are connected by ports 11a 12 with the forward and rear cylinder ends respectively. The inner edges 9a of the valve are bevelled to permit easy access of fluid. The same valve may be used for hammers of different length of stroke. The valve is shown applied to a percussive rock drill in Fig. 5. The cylinder end is closed by a chest housing the valve and provided with ports communicating with its ends. A ratchet ring is housed beyond the chest in a chamber separated therefrom by a ring 28 through which the rifle bar 31 passes. A hand-operated, spring-pressed plunger 42 is housed on the side of the drill, and may be operated to lock the valve to blow the hole drilled.