GB109777A - Improvements in Percussive Rock Drills and like Fluid Pressure Operated Tools. - Google Patents

Abstract

109,777. Rayner, G. H. T., and Rayner, P. July 27, 1917. Fluid-actuated gears.-A percussive rock drill has a differential main piston b, p, the small end of which is constantly subjected to fluid pressure, and the outer large end is intermittently supplied with fluid through a port i controlled by the small end. The other side of the large piston is alternately supplied with fluid pressure controlled by a differential valve having its small end d constantly supplied with fluid pressure, its large end constantly supplied through a small port h in the valve, and its large end also alternately put to exhaust by a piston-controlled port g. Or, in the construction shown in Fig. 3, the port h, Fig. 1, is dispensed with, and the large end alternately put to pressure and exhaust by piston-controlled ports g, g<1>. In Fig. 1, the supply through port c<2> is shown cutoff by a shoulder e on the piston, and the fluid works expansively on both sides of the piston. In Fig. 3, the port c<2> is shown communicating directly with the cylinder. Leakage ports m are provided in the valve chest, and leakage recesses k are provided in the small bore of the main piston. In the construction Fig. 1, k constantly communicates with the atmosphere; in the construction Fig. 3, k alternately communicates with the atmosphere through a port controlled by a recess in the valve. Each cylinder has a piston-controlled exhaust f,