Adjustable flow control for hydraulic valves having high pressure main supply and controls fluid flow to cylinder and exhaust ports

Claim 1

An adjustable flow control for a hydraulic valve of the class above described comprising in combination; a valve body having a bore and including a high pressure main in communication therewith, cylinder ports in communication therewith, exhaust ports in communication therewith, and a high pressure loop in communication therewith, and a spool slidably disposed in said bore for selectively connecting said cylinder ports to said high pressure loop and to said exhaust ports; and flow control means disposed intermediate said high pressure main, said high pressure loop and an exhaust port, said flow control means including a flow control bore in the valve body, said flow control bore being in fluid communication with the high pressure loop, the high pressure main and an exhaust port and having flow control means disposed therein, intermediate said high pressure main, said high pressure loop and an exhaust port and further including a stationary sleeve disposed coaxially of said flow control bore having a seat for coacting with check valve means operable therein to preVent flow of fluid from said high pressure loop to said high pressure main in a first position, and to permit a variable controlled flow of fluid to said high pressure loop from said high pressure main in a second position, means adjustably disposed on said valve body for engaging said flow control means in said second position whereby said second position of said flow control means is varied so as to provide a variable orifice intermediate said flow control means and the seat therefor in said stationary sleeve, and flow control means slidably disposed coaxially on said stationary sleeve and operable in response to a predetermined pressure in the high pressure main to bypass excess fluid to an exhaust port.