초록 ▼

A fluid operated valve device which effects a time delay in the shifting of a main valve spool. Pressurized pilot fluid is metered at a controlled rate through an air filter and a spiral groove which is restricted in size to delay the pressure build up of the fluid. When the pressure builds up suffi

A fluid operated valve device which effects a time delay in the shifting of a main valve spool. Pressurized pilot fluid is metered at a controlled rate through an air filter and a spiral groove which is restricted in size to delay the pressure build up of the fluid. When the pressure builds up sufficiently, a timer piston is shifted to break its seal with the main valve spool so that fluid can pass through the piston into a pressure chamber. The fluid pressure in the chamber shifts the main valve spool to control application of fluid to the load. When the pilot pressure is relieved, fluid flows at a high speed along a return path that passes the base of the air filter to create a suction effect which extracts dirt from the filter and purges it from the system. The pressure reduction allows springs to return the main valve spool and the timer piston into sealing position. A sleeve cooperates with the pilot circuit and the timer piston to compensate for increased pilot pressure such that the time delay changes predictably with pressure changes.

대표청구항 ▼

A time delay valve device for directing pressurized fluid to a load, said device comprising: a valve body presenting a cavity therein for receiving pressurized fluid; a valve member supported on said body for movement between first and second positions to control the flow of fluid to the load; yield

A time delay valve device for directing pressurized fluid to a load, said device comprising: a valve body presenting a cavity therein for receiving pressurized fluid; a valve member supported on said body for movement between first and second positions to control the flow of fluid to the load; yieldable means urging said valve member toward the first position; a piston slidably supported on said valve body; a passage through said piston having an inlet end and an outlet end, said inlet end communicating with said cavity to receive fluid therefrom; a fluid chamber in said valve body disposed to receive fluid from the outlet end of said passage, said valve member being shiftable from the first position to the second position in response to entry of fluid into said chamber directed against an end of the valve member and opposing the bias of the yieldable means; means establishing a releasable seal for the outlet end of said passage to substantially block the flow of fluid into said chamber through said passage; a reservoir in said valve body; a metering passageway in said valve body providing communication between said cavity and reservoir, said passageway being restricted in size to meter fluid flow into said reservoir to delay the build up of pressure therein; and a pressure surface of said piston against which fluid in said reservoir acts in a manner urging said piston to slide in a direction to break said releasable seal, whereby fluid flows through said passage into said chamber to shift said valve member to the second position after a time delay sufficient for the fluid pressure in said reservoir to build up to a predetermined level.