GB495422A - Improvements relating to hydraulic control valves - Google Patents

Abstract

495,422. Hydraulic control valves. SULLIVAN MACHINERY CO. May 18, 1937, No. 13804. Convention date, May 15, 1936. [Classes 69 (ii) and 135] A hydraulic control valve for controlling the flow of liquid from a pump and reservoir circuit 21, 22 to the power cylinders 15 of a drill feeding mechanism 14, 12 in which different rates of feed are required for forward and retraction operations comprises a hollow piston member 46 in a casing 26 with a pressure fluid supply inlet 37, an exhaust outlet 42, and connections 40, 41 for pipes 20, 19 leading to the opposite ends of the cylinders 15 respectively. The valve piston 46 is provided with ports 57, 58 for controlling the exhaust from either of ports 29a or 30a at the connections 40, 41 respectively according to whether it is moved to the left or right from its neutral position shown, and annular recesses 51, 52 for the passage of the pressure fluid to the other port. Rotation of the piston 46 will increase or decrease the communication between the ports 57, 58 and 29a or 30a to regulate the exhaust of the pressure liquid to enable the rate of the feeding operation to be adjusted. In the neutral position of the valve, as shown in Fig. 2, the inlet 37 and exhaust 42 are in communication so that the pump 21 is relieved of load, and the fluid in both ends of the cylinders 15 is entrapped so that the pistons 17 are held positively against movement. Both the rotary and sliding movements of the valve 46 are effected by a single control handle 64 which is pivoted at 63 to the valve spindle and at 65 to a link 66 mounted on a rotatable ring 69 on the valve casing. The ring 69 has a lug 77 which cooperates with a pin (not shown) on an adjustable stop ring 72 which can be adjusted to enable a certain condition of feed, for example, minimum feed, to be repeated.