Load responsive control valve

Claim 2

A valve assembly comprising a housing having a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber and fluid exhaust means, first valve means for selectively interconnecting said load chamber with said inlet chamber and said outlet chamber, variable orifice means between said outlet chamber and said exhaust means and responsive to movement of said first valve means, and second valve means disposed to throttle fluid between said outlet chamber and said exhaust means and means to operate said second valve means to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized.

Claim 3

A valve assembly as set forth in claim 1 wherein said fluid throttling means are positioned between said variable orifice means and said fluid exhaust means.

Claim 4

A valve assembly as set forth in claim 1 wherein said fluid throttling means are positioned between said outlet chamber and said variable orifice means.

Claim 5

A valve assembly as set forth in claim 1 wherein said first valve means includes a valve spool axially guided in a spool bore and movable from a neutral position to at least one actuated position, said valve spool isolating said load chamber from said fluid inlet chamber and said fluid outlet chamber and said fluid outlet chamber from said fluid exhaust means when in neutral position.

Claim 6

A valve assembly as set forth in claim 4 wherein said variable orifice means are varied in relation to axial displacement of said spool with respect to said bore.

Claim 7

A valve assembly as set forth in claim 5 wherein said variable orifice means includes a metering land and metering surface means, said metering surface means determining the variation in said variable orifice means in respect to movement of said spool.

Claim 8

A valve assembly as set forth in claim 6 wherein said metering surface means have means operable to meter fluid flow between said fluid outlet chamber and said fluid exhaust means when said spool is displaced in both directions from neutral position.

Claim 9

A valve assembly comprising a housing having a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber and second fluid exhaust chamber, first valve means for selectively inter-connecting said load chamber with said inlet chamber and said outlet chamber, said first valve means including a valve spool axially guided in a spool bore and movable from a neutral position to at least one actuated position, said valve spool isolating said load chamber from said fluid inlet chamber and said fluid outlet chamber and said fluid outlet chamber from said fluid exhaust chamber when in neutral position, variable orifice means interconnecting said outlet chamber and said first exhaust chamber and responsive to movement of said first valve means, and second valve means interconnecting said first exhaust chamber and said second exhaust chamber operable to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized.

Claim 10

A valve assembly comprising a housing having a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber and second fluid exhaust chamber, first valve means for selectively inter-connecting said load chamber with said inlet chamber and said outlet chamber, said first valve means including a valve spool axially guided in a spool bore and movable from a neutral position to at least one actuated position, said valve spool isolating said load chamber from said fluid inlet chamber and said fluid outlet chamber and said fluid outlet chamber from said fluid exhaust chamber when in neutral position, variable orifice means interconnecting said outlet chamber and said first exhaust chamber and responsive to movement of said first valve means, and second valve means interconnecting said first exhaust chamber and said second exhaust chamber operable to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized.

Claim 11

A valve assembly as set forth in claim 8 wherein said second valve means is responsive to pressure in said fluid outlet chamber.

Claim 12

A valve assembly as set forth in claim 8 wherein said second valve means has throttling means to throttle fluid from said first fluid exhaust chamber to said second fluid exhaust chamber.

Claim 13

A valve assembly as set forth in claim 8 wherein said valve spool has a fluid metering means between said fluid outlet chamber and said first fluid exhaust chamber, said fluid metering means movable from a neutral position to at least one control position and when in neutral position said metering means isolating said fluid outlet chamber from said first fluid exhaust chamber.

Claim 14

A valve assembly as set forth in claim 8 wherein said second valve means includes a control spool guided in a bore interconnecting said first fluid exhaust chamber and said second fluid exhaust chamber said control spool being biased in one direction by pressure in said first exhaust chamber and by spring means and in the other direction by pressure in said outlet chamber.

Claim 15

A valve assembly comprising a housing having a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber, a second fluid exhaust chamber and fluid exhaust means said exhaust chambers being between said outlet chamber and said exhaust means, first valve means for selectively interconnecting said load chamber with said inlet chamber and said outlet chamber, said first valve means including a valve spool axially guided in a spool bore and movable from a neutral position to at least one actuated position, said valve spool isolating said load chamber from said fluid inlet chamber and said fluid outlet chamber and said first fluid exhaust chamber from said second fluid exhaust chamber when in neutral position, variable orifice means interconnecting said first and second exhaust chambers and responsive to movement of said first valve means, and second valve means interconnecting said outlet chamber and said first exhaust chamber having throttling means, and means to operate said second valve means to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized.

Claim 16

A valve assembly comprising a housing having a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber, a second fluid exhaust chamber and fluid exhaust means said exhaust chambers being between said outlet chamber and said exhaust means, first valve means for selectively interconnecting said load chamber with said inlet chamber and said outlet chamber, said first valve means including a valve spool axially guided in a spool bore and movable from a neutral position to at least one actuated position, said valve spool isolating said load chamber from said fluid inlet chamber and said fluid outlet chamber and said first fluid exhaust chamber from said second fluid exhaust chamber when in neutral position, variable orifice means interconnecting said first and second exhaust chambers and responsive to movement of said first valve means, and second valve means interconnecting said outlet chamber and said first exhaust chamber having throttling means, and means to operate said second valve means to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized.

Claim 17

A valve assembly as set forth in claim 13 wherein said second valve means is responsive to pressure in said first exhaust chamber.

Claim 18

A valve assembly as set forth in claim 13 wherein said second valve means has throttling means to throttle fluid from said outlet chamber to said first fluid exhaust chamber.

Claim 19

A valve assembly as set forth in claim 13 wherein said valve spool has a fluid metering means between said first fluid exhaust chamber and said second fluid exhaust chamber, said fluid metering means movable from a neutral position to at least one control position and when in neutral position said metering means isolating said first fluid exhaust chamber from said second fluid exhaust chamber.

Claim 20

A valve assembly as set forth in claim 13 wherein said second valve means includes a control spool guided in a bore interconnecting said fluid outlet chamber and said first fluid exhaust chamber said control spool being biased in one direction by pressure in said first exhaust chamber and in the other direction by spring means.

Claim 21

A valve assembly comprising a housing having a fluid inlet port, a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber and fluid exhaust means, first valve means for selectively interconnecting said load chamber with said inlet chamber and said outlet chamber, first variable orifice means interconnecting said outlet chamber and said exhaust chamber and responsive to movement of said first valve means, and a second valve means interconnecting said exhaust chamber and said fluid exhaust means having throttling means, and means to operate said second valve means to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized and second variable orifice means interconnecting said load chamber and said inlet chamber and responsive to movement of said first valve means, and third valve means interconnecting said inlet port and said exhaust means and operable to maintain a constant pressure difference across said second variable orifice means when said inlet chamber and said load chamber are interconnected and when said load chamber is pressurized.

Claim 22

A valve assembly comprising a housing having a fluid inlet port, a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber and fluid exhaust means, first valve means for selectively interconnecting said load chamber with said inlet chamber and said outlet chamber, first variable orifice means interconnecting said outlet chamber and said exhaust chamber and responsive to movement of said first valve means, and a second valve means interconnecting said exhaust chamber and said fluid exhaust means having throttling means, and means to operate said second valve means to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized and second variable orifice means interconnecting said load chamber and said inlet chamber and responsive to movement of said first valve means, and third valve means interconnecting said inlet port and said exhaust means and operable to maintain a constant pressure difference across said second variable orifice means when said inlet chamber and said load chamber are interconnected and when said load chamber is pressurized.

Claim 23

A valve assembly as set forth in claim 18 wherein a fourth valve means interconnects said inlet port and said inlet chamber and operable to maintain a constant pressure difference across said second variable orifice means when said inlet chamber is open to said load chamber and the pressure difference between said load chamber and said inlet chamber is greater than said constant pressure difference.

Claim 24

A valve assembly as set forth in claim 18 wherein said third valve means includes a control member biased in one direction by pressure in said inlet and in the opposite direction by pressure in said load chamber and by spring means and operable to bypass fluid flow from said inlet port to said exhaust means to maintain a constant pressure difference across said second variable orifice means.

Claim 25

A valve assembly as set forth in claim 20 wherein said third valve means is connected by passage means with said load chamber, said passage means beiNg closed by said first valve means when said first valve means is in neutral position, said first valve means when moved from its neutral position first interconnecting by said passage means said load chamber to said third valve means and then connecting said load chamber to said inlet chamber.

Claim 26

A valve assembly comprising a housing having a fluid inlet port, a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber, a second fluid exhaust chamber and fluid exhaust means said exhaust chambers being between said outlet chamber and said exhaust means, first valve means for selectively interconnecting said load chamber with said inlet chamber and said outlet chamber, first variable orifice means interconnecting said first and second exhaust chambers and responsive to movement of said first valve means, second valve means interconnecting said outlet chamber and said first exhaust chamber having throttling means, and means to operate said second valve means to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized, seconnd variable orifice means interconnecting said load chamber and said inlet chamber and responsive to movement of said first valve means, and third valve means interconnecting said inlet port and said exhaust means and operable to maintain a constant pressure difference across said second variable orifice means when said inlet chamber and said load chamber are interconnected and when said load chamber is pressurized.

Claim 27

A valve assembly comprising a housing having a fluid inlet port, a fluid inlet chamber, a fluid load chamber, a fluid outlet chamber, a first fluid exhaust chamber, a second fluid exhaust chamber and fluid exhaust means said exhaust chambers being between said outlet chamber and said exhaust means, first valve means for selectively interconnecting said load chamber with said inlet chamber and said outlet chamber, first variable orifice means interconnecting said first and second exhaust chambers and responsive to movement of said first valve means, second valve means interconnecting said outlet chamber and said first exhaust chamber having throttling means, and means to operate said second valve means to maintain a constant pressure difference across said variable orifice means when said load chamber and said outlet chamber are interconnected and said outlet chamber is pressurized, seconnd variable orifice means interconnecting said load chamber and said inlet chamber and responsive to movement of said first valve means, and third valve means interconnecting said inlet port and said exhaust means and operable to maintain a constant pressure difference across said second variable orifice means when said inlet chamber and said load chamber are interconnected and when said load chamber is pressurized.

Claim 28

A valve assembly as set forth in claim 22 wherein a fourth valve means interconnects said inlet port and said inlet chamber and operable to maintain a constant pressure difference across said second variable orifice means, when said inlet chamber is open to said load chamber and the pressure difference between said load chamber and said inlet chamber is greater than said constant pressure difference.

Claim 29

The valve assembly as set forth in claim 22 wherein said third valve means includes a control member biased in one direction by pressure in said inlet port and in the opposite direction by pressure in said load chamber and by spring means and operable to bypass fluid flow from said inlet port to said exhaust means to maintain a constant pressure difference across said second variable orifice means.

Claim 30

A valve assembly as set forth in claim 24 wherein said third valve means is connected by a passage means with said load chamber, said passage means being closed by said first valve means when said first valve means is in neutral position, said first valve means when moved from its neutral position first interconnecting by said passage means said load chamber to said third valve means and then connecting said load chamber to said inlet chamber.

Claim 31

A fourway fluid control valve assembly comprising a housing having an inlet chamber, first and second load chambers, an outlet chamber and an exhaust chamber, a valve bore in direct communication with said aforementioned chambers, said valve bore axially guiding a valve spool having sequencing lands and a metering land, said sequencing lands isolating said inlet chamber said outlet chamber and said first and second load chambers, and said metering land isolating said outlet chamber from said exhaust chamber, exhaust means in said housing, valve means interconnecting said exhaust chamber and said exhaust means and operable to maintain a constant pressure differential across said metering land when one of said load chambers is connected to said outlet chamber and said outlet chamber is pressurized, said valve means including a control spool guided in a control bore, fluid throttling means on said control spool to control fluid flow between said exhaust chamber and said exhaust means, said control spool being biased in one direction to increase fluid flow by pressure in said exhaust chamber when said control bore is conneCted thereto and by spring means, and in the other direction by pressure in said outlet chamber, when the control bore is connected thereto and said outlet chamber is pressurized, a signal passage connecting said control bore and said outlet chamber, said valve spool when displaced from its neutral position in one direction first interconnecting said first load chamber to said inlet chamber and said second load chamber to said outlet chamber and then connecting said exhaust chamber to said outlet chamber by said metering land, said metering land having metering surface means to regulate the area of fluid flow between said outlet chamber and said exhaust chamber with respect to movement of said valve spool in said one direction, said valve spool when displaced from its neutral position in the opposite direction first interconnecting said first load chamber to said outlet chamber and said second load chamber to said inlet chamber and then connecting said exhaust chamber to said outlet chamber by said said metering land, said metering land having metering surface means to regulate the area of flow between said outlet chamber and said exhaust chamber with respect to movement of the valve spool in said opposite direction, whereby valve will control a load under negative load conditions.

Claim 32

A fourway fluid control valve assembly comprising a housing having an inlet chamber, first and second load chambers, an outlet chamber and an exhaust chamber, a valve bore in direct communication with said aforementioned chambers, said valve bore axially guiding a valve spool having sequencing lands and a metering land, said sequencing lands isolating said inlet chamber said outlet chamber and said first and second load chambers, and said metering land isolating said outlet chamber from said exhaust chamber, exhaust means in said housing, valve means interconnecting said exhaust chamber and said exhaust means and operable to maintain a constant pressure differential across said metering land when one of said load chambers is connected to said outlet chamber and said outlet chamber is pressurized, said valve means including a control spool guided in a control bore, fluid throttling means on said control spool to control fluid flow between said exhaust chamber and said exhaust means, said control spool being biased in one direction to increase fluid flow by pressure in said exhaust chamber when said control bore is conneCted thereto and by spring means, and in the other direction by pressure in said outlet chamber, when the control bore is connected thereto and said outlet chamber is pressurized, a signal passage connecting said control bore and said outlet chamber, said valve spool when displaced from its neutral position in one direction first interconnecting said first load chamber to said inlet chamber and said second load chamber to said outlet chamber and then connecting said exhaust chamber to said outlet chamber by said metering land, said metering land having metering surface means to regulate the area of fluid flow between said outlet chamber and said exhaust chamber with respect to movement of said valve spool in said one direction, said valve spool when displaced from its neutral position in the opposite direction first interconnecting said first load chamber to said outlet chamber and said second load chamber to said inlet chamber and then connecting said exhaust chamber to said outlet chamber by said said metering land, said metering land having metering surface means to regulate the area of flow between said outlet chamber and said exhaust chamber with respect to movement of the valve spool in said opposite direction, whereby valve will control a load under negative load conditions.

Claim 33

A fourway fluid control valve assembly comprising a housing having an inlet chamber, first and second load chambers, an outlet chamber and first and second exhaust chambers, a valve bore in direct communication with said aforementioned chambers, said valve bore axially guiding a valve spool having sequencing lands and a metering land, said sequencing lands isolating said inlet chamber said outlet chamber and said first and second load chambers, and said metering land isolating said first exhaust chamber from said second exhaust chamber, exhaust means in said housing, valve means interconnecting said outlet chamber and said first exhaust means and operable to maintain a constant pressure differential across said metering land when one of said load chambers is connected to said outlet chamber and said outlet chamber is pressurized, said valve means including control spool guided in a control bore, fluid throttling means on said control spool to control fluid flow between said outlet chamber and said first exhaust chamber, said control spool being biased in one direction to increase fluid flow by pressure in said second exhaust chamber and by spring means, and in the other direction by pressure in said first exhaust chamber when the control bore is connected thereto and said outlet chamber is pressurized, a signal passage connecting said control bore and second exhaust chamber, said valve spool when displaced from its neutral position in one direction first interconnecting said first load chamber to said inlet chamber and said second load chamber to said outlet chamber, and the connecting said first exhaust chamber to said second exhaust chamber by said metering land, said metering land having metering surface means to regulate the area of fluid flow between said first exhaust chamber and said second exhaust chamber in respect to movement of said valve spool in said one direction, said valve spool when displaced from neutral position in the opposite direction first interconnecting said first load chamber to said outlet chamber and said second load chamber to said inlet chamber, and the connecting said first exhaust chamber to said second exhaust chamber by said metering land, said metering land having metering surface means to regulate the area of flow between said first and second exhaust chambers in respect to movement of the valve spool in said opposite direction, whereby valve will control a load under negative load conditions.

Claim 34

A fourway fluid control valve assembly comprising a housing having an inlet chamber, first and second load chambers, an outlet chamber and first and second exhaust chambers, a valve bore in direct communication with said aforementioned chambers, said valve bore axially guiding a valve spool having sequencing lands and a metering land, said sequencing lands isolating said inlet chamber said outlet chamber and said first and second load chambers, and said metering land isolating said first exhaust chamber from said second exhaust chamber, exhaust means in said housing, valve means interconnecting said outlet chamber and said first exhaust means and operable to maintain a constant pressure differential across said metering land when one of said load chambers is connected to said outlet chamber and said outlet chamber is pressurized, said valve means including control spool guided in a control bore, fluid throttling means on said control spool to control fluid flow between said outlet chamber and said first exhaust chamber, said control spool being biased in one direction to increase fluid flow by pressure in said second exhaust chamber and by spring means, and in the other direction by pressure in said first exhaust chamber when the control bore is connected thereto and said outlet chamber is pressurized, a signal passage connecting said control bore and second exhaust chamber, said valve spool when displaced from its neutral position in one direction first interconnecting said first load chamber to said inlet chamber and said second load chamber to said outlet chamber, and the connecting said first exhaust chamber to said second exhaust chamber by said metering land, said metering land having metering surface means to regulate the area of fluid flow between said first exhaust chamber and said second exhaust chamber in respect to movement of said valve spool in said one direction, said valve spool when displaced from neutral position in the opposite direction first interconnecting said first load chamber to said outlet chamber and said second load chamber to said inlet chamber, and the connecting said first exhaust chamber to said second exhaust chamber by said metering land, said metering land having metering surface means to regulate the area of flow between said first and second exhaust chambers in respect to movement of the valve spool in said opposite direction, whereby valve will control a load under negative load conditions.