GB191407224A - New or Improved Hydraulic Machine. - Google Patents

Abstract

7224. Gjuke, G. E. March 22, 1913, [Con vention date]. Void. [Published under section 91 of the Act.] Percussive drills.-In an hydraulic rock drill, the cylinder, slide valve, and valve-chest are so arranged that, on reversing the valve, no sudden change in pressure occurs, and the pressure in the cylinder can never exceed the maximum pressure in the supply pipe. In the form shown in Fig. 1, water from the inlet 8 passes through a port 20 to move the piston 1 forward. An annular groove 17 in the piston admits water from ports 3, 18 through the first port 21 and passage 5 to a chamber 10 to hold the valve 7 to 'the left. When the groove 17 connects the two ports 21, the chamber 10 is opened to exhaust 13 through passage 5, ports 21, passage 4, chamber 9, and ports 12, 11 in the valve; the valve then moves to the right. The rear end of the cylinder is then opened to exhaust, and the fluid constantly supplied through port 3 moves the piston rearward. When the groove 17 connects port 18 with the first port 21, the valve is moved to the left to admit fluid to the rear end of the cylinder again. A sudden increase in pressure is prevented by making the valve head 19 narrower than the port 20, so that the inlet 8 momentarily communicates with the exhaust 13. In the form shown in Fig. 2, fluid admitted through ports 25, 34, 27, 35 moves the piston forward. When the port 34 is closed, fluid in the chamber 40 moves the valve 24 forward, opening the rear cylinder space to exhaust through ports 32, 31, 33, 26, and the piston is then returned by the constant pressure at its forward end. When the piston closes ports 32, the increase of pressure causes the valve to move rearward, and fluid enters ports 35 to move the piston forward. The increase in the rear cylinder space due to the rearward movement of the valve prevents a sudden rise in pressure.