Load responsive fluid control system

Claim 2

Multiple load responsive valve assemblies each comprising a housing having a fluid inlet chamber connected to pump means, a fluid supply chamber, first and second load chambers, outlet fluid conducting means, fluid exhaust means connected to reservoir means and pressure sensing means, first valve means for selectively interconnecting said fluid load chambers with said pressure sensing means, said fluid supply chamber and said fluid exhaust means, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid flow between said load chambers and said fluid exhaust means, second valve means having first fluid throttling and fluid isolating means between said fluid inlet chamber and said fluid supply chamber and second fluid throttling means between said load chambers and said fluid exhaust means, said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential at a relatively constant level while pressure at said variable orifice means is permitted to vary, fluid replenishing means to interconnect for fluid flow said fluid supply chamber and said fluid exhaust means when said fluid isolating means isolates said fluid supply chamber from said fluid inlet chamber and control means operably connected through said pump means to said inlet chambers of said valve assemblies, control line means interconnecting said control means with said pressure sensing means of said valve assemblies, control signal direction phasing means in each of said control line means, said control means responsive to highest pressure in any of said load chambers of valve assemblies operating loads and operable to vary fluid flow delivered from said pump means to load system to maintain a constant pressure differential between pressure in said inlet chambers and said maximum pressure in said load chamber.

Claim 3

Multiple load responsive valve assemblies as set forth in claim 1 wherein said first valve means includes a valve spool axially guided in a valve bore and movable from a neutral position to at least two actuated positions, said valve spool isolating said load chambers from said supply chamber and said fluid exhaust means when in neutral position and when displaced from neutral position first uncovering a control signal passage means in the region of said spool bore between one of said load chambers and said fluid supply chamber.

Claim 4

Multiple load responsive valve assemblies as set forth in claim 1 wherein said fluid replenishing means have fluid connecting means on said second valve means operable to connect for fluid flow said fluid supply chamber with said fluid exhaust means when said fluid isolating means isolates said fluid inlet chamber from said fluid supply chamber.

Claim 5

Multiple load responsive valve assemblies as set forth in claim 1 wherein said fluid replenishing means have suction check valve means interconnecting for one way fluid flow said fluid exhaust means and said fluid supply chambers.

Claim 6

Multiple load responsive valve assemblies as set forth in claim 4 wherein duct means interconnect said fluid exhaust means of said valve assemblies with said reservoir means, exhaust pressure relief valve means in said duct means interposed between said valve assemblies and said reservoir means said suction check valve means interconnecting said fluid supply chambers of said valve assemblies through said fluid exhaust means with said duct means upstream of said exhaust pressure relief valve means.

Claim 7

Multiple load responsive valve assemblies as set forth in claim 1 wherein said control means has bypass means to vary fluid flow delivered from said pump means to said load system and fluid conducting means to conduct said fluid from said bypass means to said fluid replenishing means.

Claim 8

Multiple load responsive valve assemblies as set forth in claim 1 wherein said control means has pump displacement changing control means to vary fluid flow delivered from said pump means to said multiple load responsive valve assemblies.

Claim 9

Multiple load responsive valve assemblies as set forth in claim 7 wherein constant pressure reducing valve means interconnects said inlet chambers of said valve assemblies and said fluid exhaust means, duct means interconnecting said fluid exhaust means of said valve assemblies with said reservoir means, exhaust pressure relief valve means in said duct means interposed between said valve assemblies and said reservoir means, said constant pressure reducing valve means operable to maintain said duct means upstream of said exhaust pressure relief valve means at a constant pressure level lower than pressure setting of said exhaust pressure relief valve means when said exhaust pressure relief valve means stop passing fluid from said load responsive valve assemblies to said reservoir means.

Claim 10

Multiple load responsive valve assemblies as set forth in claim 1 wherein said first throttling means has means operable to control fluid flow from said fluid inlet chamber to said fluid supply chamber to maintain said pressure differential across said variable orifice means at a first relatively constant preselected level when one of said load chambers is interconnected with said fluid supply chamber and said load chamber is pressurized.

Claim 11

Multiple load responsive valve assemblies as set forth in claim 9 wherein said second throttling means has means operable to control fluid flow from said load chamber to said exhaust means to maintain said pressure differential across said variable orifice means at a second relatively constant preselected level when one of said load chambers is connected through said variable orifice means to said exhaust means and said load chamber is pressurized.

Claim 12

Multiple load responsive valve assemblies as set forth in claim 1 wherein said housing has a fluid outlet chamber selectively communicable with said load chambers and a fluid exhaust chamber communicable with said exhaust means, said variable metering orifice means selectively interconnecting for fluid flow said fluid outlet chamber and said fluid exhaust chamber.

Claim 13

Multiple load responsive valve assemblies as set forth in claim 11 wherein said second throttling means is positioned to throttle fluid flow between said fluid exhaust chamber and said fluid exhaust means.

Claim 14

Multiple load responsive valve assemblies as set forth in claim 11 wherein said second valve means is responsive to pressure in said fluid outlet chamber and said fluid exhaust chamber.

Claim 15

Multiple load responsive valve assemblies as set forth in claim 1 wherein said control signal direction phasing means include check valve means.

Claim 16

A load responsive valve assembly comprising a housing having a fluid inlet chamber connected to pump means, a fluid supply chamber, first and second load chambers, outlet fluid conducting means, fluid exhaust means connected to reservoir means and pressure sensing means, first valve means for selectively interconnecting said fluid load chambers with said pressure sensing means, said fluid supply chamber and said fluid exhaust means, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid flow between said load chambers and said fluid exhaust means, second valve means having first throttling means between said fluid inlet chamber and said fluid supply chamber and second fluid throttling means between said load chambers and said fluid exhaust means, said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential at a relatively constant level while pressure at said variable orifice means is permitted to vary, said second valve means having isolating means to isolate said fluid supply chamber from said fluid inlet chamber and connecting means to connect said fluid supply chamber with said exhaust means when said fluid supply chamber is connected to one of said load chambers by said first valve means and said load chamber is not pressurized, duct means interconnecting said fluid exhaust means of said valve assembly with said reservoir means, exhaust pressure relief valve means interposed between said duct means and said reservoir means, suction check valve means interconnecting said duct means and said fluid supply chamber of said valve assembly and control means operably connected through said pump means to said inlet chamber of said valve assembly, control line means interconnecting said control means with said pressure sensing means of said valve assembly, check valve means in said control line means, said control means responsive to pressure in said load chamber of said valve assembly operating load and operable to vary fluid flow delivered from said pump means to said valve assembly to maintain a constant pressure differential between pressure is said inlet chamber and said pressure in said load chamber.

Claim 17

A load responsive valve assembly comprising a housing having a fluid inlet chamber connected to pump means, a fluid supply chamber, first and second load chambers, outlet fluid conducting means, fluid exhaust means connected to reservoir means and pressure sensing means, first valve means for selectively interconnecting said fluid load chambers with said pressure sensing means, said fluid supply chamber and said fluid exhaust means, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid flow between said load chambers and said fluid exhaust means, second valve means having first throttling means between said fluid inlet chamber and said fluid supply chamber and second fluid throttling means between said load chambers and said fluid exhaust means, said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential at a relatively constant level while pressure at said variable orifice means is permitted to vary, said second valve means having isolating means to isolate said fluid supply chamber from said fluid inlet chamber and connecting means to connect said fluid supply chamber with said exhaust means when said fluid supply chamber is connected to one of said load chambers by said first valve means and said load chamber is not pressurized, duct means interconnecting said fluid exhaust means of said valve assembly with said reservoir means, exhaust pressure relief valve means interposed between said duct means and said reservoir means, suction check valve means interconnecting said duct means and said fluid supply chamber of said valve assembly and control means operably connected through said pump means to said inlet chamber of said valve assembly, control line means interconnecting said control means with said pressure sensing means of said valve assembly, check valve means in said control line means, said control means responsive to pressure in said load chamber of said valve assembly operating load and operable to vary fluid flow delivered from said pump means to said valve assembly to maintain a constant pressure differential between pressure is said inlet chamber and said pressure in said load chamber.

Claim 18

A load responsive valve assembly as set forth in claim 15 wherein said control means has fluid bypass means to vary fluid flow delivered from said pump means and fluid conducting means to conduct said fluid from said bypass means to said duct means upstream of said exhaust pressure relief valve means.

Claim 19

A load responsive valve assembly as set forth in claim 15 wherein said first valve means includes a valve spool axially guided in a valve bore and movable from a neutral position to at least two actuated positions, said valve spool isolating said load chambers from said supply chamber and said fluid exhaust means when in neutral position and when displaced from neutral position first uncovering a control signal passage means in the region of said spool bore between one of said load chambers and said fluid supply chamber.

Claim 20

A load responsive valve assembly as set forth in claim 15 wherein said housing has a fluid outlet chamber selectively communicable with said load chambers and a fluid exhaust chamber communicable with said exhaust means, said variable metering orifice means selectively interconnecting for fluid flow said fluid outlet chamber and said fluid exhaust chamber.

Claim 21

A load responsive valve assembly as set forth in claim 18 wherein said second throttling means is positioned to throttle fluid flow between said fluid exhaust chamber and said fluid exhaust means.

Claim 22

A load responsive valve assembly as set forth in claim 18 wherein said second valve means is responsive to pressure in said fluid outlet chamber and said fluid exhaust chamber.

Claim 23

A load responsive valve assembly as set forth in claim 15 wherein said housing has a fluid bypass chamber adjacent to said fluid inlet chamber, said second valve means having priority throttling and bypass means operable to throttle or bypass flow from said fluid inlet chamber to said fluid bypass chamber.

Claim 24

A load responsive valve assembly as set forth in claim 21 wherein said second valve means has bypass actuating means to open communication through said priority throttling and bypass means between said fluid inlet chamber and said fluid bypass chamber when said first valve means is in a neutral position and said variable orifice means remains closed.

Claim 25

A load responsive valve assembly as set forth in claim 15 wherein said housing has a fluid outlet chamber interposed between said load chambers and said fluid exhaust means, said variable metering orifice means selectively interconnecting one of said load chambers with said outlet chamber.

Claim 26

A load responsive valve assembly as set forth in claim 15 wherein said first valve means includes a valve spool axially guided in a valve bore and movable from a neutral position to at least two actuated positions, an outlet chamber in said housing, said valve spool isolating said load chambers from said supply chamber and said outlet chamber when in neutral position and when displaced from neutral position position first uncovering a control signal port means in the region of said valve spool bore between one of said load chambers and said fluid outlet chamber.

Claim 27

A load responsive valve assembly as set forth in claim 24 wherein said second valve means is responsive to pressure in said control signal port means and pressure in said outlet fluid conducting means.

Claim 28

A load responsive valve assembly as set forth in claim 15 wherein said control means has pump displacement changing control means to vary fluid flow delivered from said pump means to said load responsive valve assembly.

Claim 29

A load responsive valve assembly as set forth in claim 26 wherein constant pressure reducing valve means interconnects said inlet chamber of said valve assembly and said duct means upstream of said exhaust pressure relief valve means and operable to maintain said duct means upstream of said exhaust pressure relief valve means at a constant pressure level lower than pressure setting of said exhaust pressure relief valve means when said exhaust pressure relief valve means stop passing fluid from said load responsive valve assembly.

Claim 30

A load responsive valve assembly comprising a housing having a fluid inlet chamber connected to pump means, a fluid supply chamber, first and second load chambers, outlet fluid conducting means, fluid exhaust means connected to reservoir means and pressure sensing port means, first valve means for selectively interconnecting said fluid load chambers with said pressure sensing port means, said fluid supply chamber and said fluid exhaust means, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid flow between said load chambers and said fluid exhaust means, second valve means having fluid throttling means, fluid isolating means between said fluid inlet chamber and said fluid supply chamber, said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential at a relatively constant level while pressure at said variable orifice means is permitted to vary, fluid replenishing means to interconnect for fluid flow said fluid supply chamber and said fluid exhaust means when said fluid isolating means isolates said fluid supply chamber from said fluid inlet chamber and control means operably connected through said pump means to said inlet chamber of said valve assembly, control line means interconnecting said control means with said pressure sensing port means of said valve assembly, control signal direction phasing means in said control line means, said control means responsive to pressure in said load chambers of said valve assembly operating a load and operable to vary fluid flow delivered from said pump means to said valve assembly to maintain a constant pressure differential between pressure in said inlet chamber and said maximum pressure in said load chamber.

Claim 31

A load responsive valve assembly comprising a housing having a fluid inlet chamber connected to pump means, a fluid supply chamber, first and second load chambers, outlet fluid conducting means, fluid exhaust means connected to reservoir means and pressure sensing port means, first valve means for selectively interconnecting said fluid load chambers with said pressure sensing port means, said fluid supply chamber and said fluid exhaust means, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid flow between said load chambers and said fluid exhaust means, second valve means having fluid throttling means, fluid isolating means between said fluid inlet chamber and said fluid supply chamber, said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential at a relatively constant level while pressure at said variable orifice means is permitted to vary, fluid replenishing means to interconnect for fluid flow said fluid supply chamber and said fluid exhaust means when said fluid isolating means isolates said fluid supply chamber from said fluid inlet chamber and control means operably connected through said pump means to said inlet chamber of said valve assembly, control line means interconnecting said control means with said pressure sensing port means of said valve assembly, control signal direction phasing means in said control line means, said control means responsive to pressure in said load chambers of said valve assembly operating a load and operable to vary fluid flow delivered from said pump means to said valve assembly to maintain a constant pressure differential between pressure in said inlet chamber and said maximum pressure in said load chamber.

Claim 32

A load responsive valve assembly as set forth in claim 28 wherein said first valve means includes a valve spool axially guided in a valve bore and movable from a neutral position to at least two actuated positions, said valve spool isolating said load chambers from said supply chamber and said fluid exhaust means when in neutral position and when displaced from neutral position first uncovering a control signal passage means in the region of said spool bore between one of said load chambers and said fluid supply chamber.

Claim 33

A load responsive valve assembly as set forth in claim 28 wherein said fluid replenishing means have fluid connecting means on said second valve means operable to connect for fluid flow said fluid supply chamber with said fluid exhaust means when said fluid isolating means isolates said fluid inlet chamber from said fluid supply chamber.

Claim 34

A load responsive valve assembly as set forth in claim 28 wherein said fluid replenishing means have suction check valve means interconnecting for one way fluid flow said fluid exhaust means and said fluid supply chamber.

Claim 35

A load responsive valve assembly as set forth in claim 28 wherein exhaust pressure relief valve means in said fluid exhaust means is interposed between said valve assembly and said reservoir means.

Claim 36

A load responsive valve assembly as set forth in claim 28 wherein said control means has bypass means to vary fluid flow delivered from said pump means to said load system and fluid conducting means to conduct said fluid from said bypass means to said fluid replenishing means.

Claim 37

A load responsive valve assembly as set forth in claim 28 wherein said control means has pump displacement changing control means to vary fluid flow delivered from said pump means to said load responsive valve assembly.

Claim 38

A load responsive valve assembly as set forth in claim 28 wherein said throttling means has means operable to control fluid flow from said fluid inlet chamber to said fluid supply chamber to maintain said pressure differential across said variable orifice means at a relatively constant preselected level when one of said load chambers is interconnected with said fluid supply chamber and said load chamber is pressurized.

Claim 39

A load responsive valve assembly as set forth in claim 28 wherein said housing has a fluid outlet chamber selectively communicable with said load chambers and a fluid exhaust chamber selectively communicable with said exhaust means, said variable metering orifice means selectively interconnecting for fluid flow said fluid outlet chamber and said fluid exhaust chamber.

Claim 40

A load responsive valve assembly as set forth in claim 28 wherein said housing has a fluid bypass chamber adjacent to said fluid inlet chamber, said second valve means having priority throttling and bypass means operable to throttle or bypass flow from said fluid inlet chamber to said fluid bypass chamber.

Claim 41

A valve assembly comprising a housing having a fluid inlet chamber, a fluid supply chamber, first and second load chambers, an outlet chamber, an exhaust chamber, and fluid exhaust means, first valve means for selectively interconnecting said fluid load chambers with said fluid outlet chamber and said fluid supply chamber, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid between said outlet chamber and said exhaust chamber, second valve means having fluid throttling means, fluid isolating means between said inlet chamber and said supply chamber, said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential relatively constant while pressure at said variable orifice means is permitted to vary, and fluid replenishing means to interconnect for fluid flow said fluid supply chamber and said fluid exhaust means when said fluid isolating means isolates fluid supply chamber from said fluid inlet chamber.

Claim 42

A valve assembly comprising a housing having a fluid inlet chamber, a fluid supply chamber, first and second load chambers, an outlet chamber, an exhaust chamber, and fluid exhaust means, first valve means for selectively interconnecting said fluid load chambers with said fluid outlet chamber and said fluid supply chamber, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid between said outlet chamber and said exhaust chamber, second valve means having fluid throttling means, fluid isolating means between said inlet chamber and said supply chamber, said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential relatively constant while pressure at said variable orifice means is permitted to vary, and fluid replenishing means to interconnect for fluid flow said fluid supply chamber and said fluid exhaust means when said fluid isolating means isolates fluid supply chamber from said fluid inlet chamber.

Claim 43

A valve assembly as set forth in claim 38 wherein said fluid replenishing means have fluid connecting means on said second valve means to connect said fluid supply chamber to said fluid exhaust means when said isolating means isolate said fluid supply chamber from said fluid inlet chamber.

Claim 44

A valve assembly as set forth in claim 38 wherein said fluid replenishing means have check valve means interconnecting for one way fluid flow said fluid exhaust means and said supply chamber.

Claim 45

A valve assembly as set forth in claim 38 wherein said exhaust means is connected to an exhaust relief valve means.

Claim 46

A valve assembly as set forth in claim 38 wherein said first valve means includes a valve spool axially guided in a valve bore and movable from a neutral position to at least two actuated positions, control signal passage means in the region of said spool bore between said load chambers and said supply chamber, said valve spool isolating said load chambers from said supply chamber and said outlet chamber and blocking said control signal passage means when in neutral position and when displaced from neutral position uncovering said control signal passage means.

Claim 47

A valve assembly as set forth in claim 42 wherein said control signal passage means have connecting passage means for connecting said control signal passage means with pump flow control means.

Claim 48

A valve assembly as set forth in claim 38 wherein said housing has a fluid bypass chamber adjacent to said fluid inlet chamber, said second valve means having priority throttling and bypass means operable to throttle or bypass flow from said fluid inlet chamber to said fluid bypass chamber.

Claim 49

A valve assembly as set forth in claim 44 wherein said second valve means has bypass actuating means to open communication through said priority throttling means and bypass means between said fluid inlet chamber and said fluid bypass chamber when said first valve means is in a neutral position isolating said load chambers from said supply chamber and said outlet chamber.

Claim 50

A valve assembly as set forth in claim 45 wherein said bypass actuating means has positioning means of said second valve means to maintain full flow communication between said inlet chamber and said bypass chamber.

Claim 51

A valve assembly as set forth in claim 38 wherein said second valve means has throttling means between said exhaust chamber and said fluid exhaust means, said second valve means being responsive to pressure differential across said variable metering orifice means.

Claim 52

A valve assembly supplied with pressure fluid by a pump, said valve assembly comprising a housing having a fluid inlet chamber, a fluid supply chamber, first and second load chambers, load pressure sensing means operable to transmit a control signal to control means operable to vary flow delivered from said pump to said inlet chamber, and fluid exhaust means, first valve means for selectively interconnecting said fluid load chambers with said load pressure sensing means, said fluid supply chamber and said fluid exhaust means, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid flow between said load chambers and said fluid exhaust means, second valve means having fluid throttling means said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential at a relatively constant level while pressure at said variable orifice means is permitted to vary, said second valve means having isolating means to isolate said fluid supply chamber from said fluid inlet chamber, and connecting means to connect said fluid supply chamber with said exhaust means when said fluid supply chamber is connected to one of said load chambers by said first valve means and said load chamber is not pressurized.

Claim 53

A valve assembly supplied with pressure fluid by a pump, said valve assembly comprising a housing having a fluid inlet chamber, a fluid supply chamber, first and second load chambers, load pressure sensing means operable to transmit a control signal to control means operable to vary flow delivered from said pump to said inlet chamber, and fluid exhaust means, first valve means for selectively interconnecting said fluid load chambers with said load pressure sensing means, said fluid supply chamber and said fluid exhaust means, variable metering orifice means responsive to movement of said first valve means and operable to throttle fluid flow between said load chambers and said fluid exhaust means, second valve means having fluid throttling means said second valve means having means responsive to pressure differential at variable pressure level acting across said variable orifice means and operable to maintain said pressure differential at a relatively constant level while pressure at said variable orifice means is permitted to vary, said second valve means having isolating means to isolate said fluid supply chamber from said fluid inlet chamber, and connecting means to connect said fluid supply chamber with said exhaust means when said fluid supply chamber is connected to one of said load chambers by said first valve means and said load chamber is not pressurized.

Claim 54

A valve assembly as set forth in claim 48 wherein said second valve means has fluid throttling means between said load chambers and said fluid exhaust means.

Claim 55

A valve assembly as set forth in claim 48 wherein exhaust pressure relief valve means is positioned in said fluid exhaust means.

Claim 56

A valve assembly as set forth in claim 50 wherein constant pressure reducing valve means interconnects said inlet chamber of said valve assembly and said fluid exhaust means upstream of said exhaust pressure relief valve means and operable to maintain said fluid exhaust means upstream of said exhaust pressure relief valve means at a constant pressure lever lower than pressure setting of said exhaust pressure relief valve means when said exhaust pressure relief valve means stop passing fluid from said fluid exhaust means.