Cartridge valve

Claim 2

A valve for supplying fluid to and exhausting fluid from a fluid user, said valve comprising: a housing provided with an inlet port, an outlet port and an exhaust port, said housing having an axial bore and said inlet port, outlet port and exhaust port all registering with said bore; a valve member axially movably mounted within said housing bore and being provided with means operable to close communication between said inlet port and outlet port, and to open communication between said outlet port and said exhaust port at a first axial position of said valve member and to open communication between said inlet port and said outlet port and to close communication between said outlet port and said exhaust port at a second axial position of said valve member; and means forming a pair of expansible pressure chambers, one of which is in fluid communication with said inlet port and a restricted passageway connecting said pressure chambers, said valve member being shiftable to said first axial position when said pressure chambers are at substantially equal pressures, and means for exhausting the other of said pressure chambers to create a pressure differential between said pressure chambers, said valve member being shifted to said second axial passage in response to said pressure differential.

Claim 3

The valve as defined in claim 1 in which said means for moving said valve member between said first and second axial positions comprises a piston portion carried by said valve member, the opposite walls of said piston portion being respectively exposed to said pair of expansible pressure chambers, the wall of said piston portion exposed to said other pressure chamber having an effective pressure-responsive area greater than the effective pressure-responsive area of the other of said opposite walls.

Claim 4

The valve as defined in claim 2 including spring means urging said valve member towards said first axial position.

Claim 5

The valve as defined in claim 3 whErein said restricted passageway extends through said piston portion to fluidly connect said pressure chambers.

Claim 6

The valve defined in claim 2, wherein one end of said valve member extending below said piston portion is of a reduced diameter for slidable extension within a second bore in the bottom of said housing, said second bore communicating with said outlet portion and said one pressure chamber when said valve member is in said second axial position; means in said valve member providing communication between said axial bore and said exhaust port comprising an axial passage in said valve member connecting said reduced lower end to the opposite end of said valve member, said housing bore having a radial passageway disposed proximate said opposite end of said valve member and connecting said exhaust port and said axial passage when said valve member is in said first position and closed by said valve member to close communication between said exhaust port and said axial passage when said valve member is in said second position.

Claim 7

The valve as defined in claim 5, including spring means urging said valve member toward said first axial position; and said restricted passage extending through said piston portion to fluidly connect said pressure chambers.

Claim 8

The valve as defined in claim 6, wherein said means for exhausting said other pressure chamber comprises a pilot valve adapted to selectively exhaust the fluid in said other pressure chamber through a fluid path of a larger cross section than said restricted passageway through said piston portion, such that the opening of said pilot valve to exhaust fluid from said one pressure chamber creates a pressure differential across said piston portion causing the pressure in said one pressure chamber to exceed the pressure in said other pressure chamber so that the resultant pressure unbalance exerts a force on said piston portion to move said piston portion and thus said valve member toward said second axial position.

Claim 9

A fluid pressure control valve assembly adapted for connection between a source of fluid and a fluid user, said assembly including a first and a second valve means, said first valve means comprising a housing having an inlet for communication with said source of fluid under pressure and an outlet port; a valve member axially slidably carried in said housing having means closing fluid flow from said inlet to said outlet port in a first axial position of said valve member and means opening fluid flow from said inlet to said outlet port in a second axial position of said valve member; means resiliently urging said valve member toward said first axial position; a first exhaust port and a second exhaust port provided in said housing each connected to a reservoir; said second valve means being disposed between said second exhaust port and said reservoir to selectively control fluid flow through said second exhaust port; first passage means provided in said housing of said first valve means; second passage means associated with said valve member of said first valve means; said first and said second passage means being adapted to establish communication between said inlet and said second exhaust port and being of different cross-sectional areas to cause the creation of a pressure differential within said housing acting on said valve member to move said valve member toward said second axial position and said second valve means being operable to selectively open or close fluid communication between said inlet and said second exhaust port through said first and said second passages to thereby create said pressure differential.

Claim 10

A fluid pressure control valve assembly adapted for connection between a source of fluid and a fluid user, said assembly including a first and a second valve means, said first valve means comprising a housing having an inlet for communication with said source of fluid under pressure and an outlet port; a valve member axially slidably carried in said housing having means closing fluid flow from said inlet to said outlet port in a first axial position of said valve member and means opening fluid flow from said inlet to said outlet port in a second axial position of said valve member; means resiliently urging said valve member toward said first axial position; a first exhaust port and a second exhaust port provided in said housing each connected to a reservoir; said second valve means being disposed between said second exhaust port and said reservoir to selectively control fluid flow through said second exhaust port; first passage means provided in said housing of said first valve means; second passage means associated with said valve member of said first valve means; said first and said second passage means being adapted to establish communication between said inlet and said second exhaust port and being of different cross-sectional areas to cause the creation of a pressure differential within said housing acting on said valve member to move said valve member toward said second axial position and said second valve means being operable to selectively open or close fluid communication between said inlet and said second exhaust port through said first and said second passages to thereby create said pressure differential.

Claim 11

The fluid pressure control valve assembly as defined in claim 8, said valve member comprising a tubular stem member having an axial passage therethrough one end of which is open to said outlet port and the other end of which is closed to said second exhaust port, said tubular stem member having passage means adapted to establish communication between saId inlet and said axial passage and thus to said outlet port when said valve member is in said first axial position, piston means carried by said valve member intermediate its ends thereof dividing said housing into a lower chamber and an upper chamber, said means disposed in said upper chamber and resiliently urging said valve member toward said first axial position.

Claim 12

A valve for supplying fluid to and exhausting fluid from a fluid user, said valve comprising; a housing provided with an inlet port, an outlet port, and an exhaust port, said housing having an axial bore and said inlet port, outlet port, and exhaust port all registering with said bore; a valve member axially movably mounted within said housing bore and being provided with means operable to close communication between said inlet port and said outlet port, and to open communication between said outlet port and said exhaust port at a first axial position of said valve member; and to open communication between said inlet port and said outlet port, and to close communication between said outlet port and said exhaust port at a second axial position of said valve member; said means comprising: a spool, one end of which slidably engages the housing bore in a fluid sealing relationship to form a sleeve-type valve for opening and closing fluid communication between said exhaust port and said housing bore, the other end of said spool being adapted to engage and disengage said outlet port to form a poppet-type valve for opening and closing fluid communication between said outlet port and said inlet port, said spool having a bore extending axially therethrough from said one end to said other end; and means for moving said valve member from said first axial position to said second axial position.

Claim 13

A valve for supplying fluid to and exhausting fluid from a fluid user, said valve comprising; a housing provided with an inlet port, an outlet port, and an exhaust port, said housing having an axial bore and said inlet port, outlet port, and exhaust port all registering with said bore; a valve member axially movably mounted within said housing bore and being provided with means operable to close communication between said inlet port and said outlet port, and to open communication between said outlet port and said exhaust port at a first axial position of said valve member; and to open communication between said inlet port and said outlet port, and to close communication between said outlet port and said exhaust port at a second axial position of said valve member; said means comprising: a spool, one end of which slidably engages the housing bore in a fluid sealing relationship to form a sleeve-type valve for opening and closing fluid communication between said exhaust port and said housing bore, the other end of said spool being adapted to engage and disengage said outlet port to form a poppet-type valve for opening and closing fluid communication between said outlet port and said inlet port, said spool having a bore extending axially therethrough from said one end to said other end; and means for moving said valve member from said first axial position to said second axial position.

Claim 14

The valve as defined in claim 10 wherein said spool has an effective pressure-responsive area at said one end of said spool which is substantially equal to the effective pressure-responsive area of said other end of said spool when said spool is in said first axial position.