Control valve

Claim 2

A control valve comprising a housing, means for comparing the magnitudes of separate fluid pressures supplied thereto and movable from a normally centered position toward opposed translated positions in said housing in response to oppositely directed differentials in excess of a predetermined amount between the magnitudes of the supplied fluid pressures acting thereon, said means defining with said housing passage means for connecting one of the supplied fluid pressures in pressure fluid communication with a fluid pressure proportional to said one supplied fluid pressure in said passage means, a pair of additive areas on said first-named means and within said passage means respectively subjected to the one supplied fluid pressure and the proportional fluid pressure, an opposing area on said first named means opposed to said additive areas and subjected to the other of said supplied fluid pressures, said means being urged toward one of its translated positions against the other supplied fluid pressure acting on said opposing area in response to the one supplied fluid pressure and the proportional fluid pressure respectively acting on said additive areas to open said passage means and establish equalizing pressure fluid communication between said one supplied fluid pressure and the proportional fluid pressure when the differential between the magnitude of the one supplied fluid pressure in excess of that of the other supplied fluid pressure exceeds the predetermined amount, and only a single centering means movable in said housing for engagement with said housing and said first named means and subjected only to the other supplied fluid pressure, said single centering means being urged in response to the other supplied fluid pressure acting thereon toward engagement with said housing and with said first-named means to oppose movement thereof toward its one translated position when the differential between the magnitudes of the one and other supplied fluid pressures respectively acting on one of said additive areas and said opposing area is less than the predetermined amount.

Claim 3

A control valve according to claim 1, wherein said one additive area subjected to the one supplied fluid pressure is substantially equal to said opposing area.

Claim 4

A control valve according to claim 1, comprising another opposing area on said single centering means additive to said first-named opposing area and subjected only to the other supplied fluid pressure, said single centering means being urged toward engagement with said housing and with said first-named means to oppose movement thereof toward its one translated position in response to the other supplied fluid pressure acting on said other opposing area.

Claim 5

A control valve according to claim 3, wherein said other opposing area is greater than one of said one and other of said additive areas.

Claim 6

A control valve according to claim 3, wherein said one additive area subjected to the one supplied fluid pressure is substantially equal to said first-named opposing area, and said other opposing area is greater than the other of said additive areas.

Claim 7

A control valve comprising a housing means displaceable in said housing from a normal centered position toward opposed translated positions including first and second opposed areas respectively subjected to one and other separately supplied fluid pressures, a third area subjected to a fluid pressure proportional to said one supplied fluid pressure and additive to said first opposed area, passage means in said housing and subjected to said one supplied fluid pressure and said proportional fluid pressure, said first-named means being movable in said passage means for controlling pressure fluiD communication therethrough between the one supplied fluid pressure and the proportional fluid pressure, said first-named means being urged toward one of its translated positions against the other of the supplied fluid pressures acting on said second opposed area in response to the one supplied fluid pressure and the proportional fluid pressure respectively acting on said first opposed area and said additive area to open said passage means and establish equalizing pressure fluid communication therethrough between the one supplied fluid pressure proportional fluid pressure when the magnitude of the one supplied fluid pressure exceeds that of the other other supplied fluid pressure by a predetermining value, and only one centering means movable in said housing for urging said first named means toward its centered position and for respective engagement with said housing including another additive area subjected only to the other supplied fluid pressure and additive to said second opposed area, said one centering means being urged toward engagement with said housing and said first-named means to oppose movement thereof toward the one translated position in response to the other supplied fluid pressure acting on said other additive area when the magnitude of the one supplied fluid pressure in excess of that of the other supplied fluid pressure is less than the predetermined value.

Claim 8

A control valve comprising a housing means displaceable in said housing from a normal centered position toward opposed translated positions including first and second opposed areas respectively subjected to one and other separately supplied fluid pressures, a third area subjected to a fluid pressure proportional to said one supplied fluid pressure and additive to said first opposed area, passage means in said housing and subjected to said one supplied fluid pressure and said proportional fluid pressure, said first-named means being movable in said passage means for controlling pressure fluiD communication therethrough between the one supplied fluid pressure and the proportional fluid pressure, said first-named means being urged toward one of its translated positions against the other of the supplied fluid pressures acting on said second opposed area in response to the one supplied fluid pressure and the proportional fluid pressure respectively acting on said first opposed area and said additive area to open said passage means and establish equalizing pressure fluid communication therethrough between the one supplied fluid pressure proportional fluid pressure when the magnitude of the one supplied fluid pressure exceeds that of the other other supplied fluid pressure by a predetermining value, and only one centering means movable in said housing for urging said first named means toward its centered position and for respective engagement with said housing including another additive area subjected only to the other supplied fluid pressure and additive to said second opposed area, said one centering means being urged toward engagement with said housing and said first-named means to oppose movement thereof toward the one translated position in response to the other supplied fluid pressure acting on said other additive area when the magnitude of the one supplied fluid pressure in excess of that of the other supplied fluid pressure is less than the predetermined value.

Claim 9

A control valve according to claim 6, wherein said first-named means includes opposed portions, and extension means on one of said opposed portions and movable in said passage means, said first opposed area being defined on said one opposed portion, said first named additive area being defined on said extension means, and said second opposed area being defined on the other of said opposed portions.

Claim 10

A control valve according to claim 6, wherein said first and second opposed areas are substantially equal, and said other additive area is greater than said first-named additive area.

Claim 11

A control valve according to claim 6, comprising abutment means on said housing for engagement with said one centering means, said one centering means being urged toward engagement with said abutment means in response to the other supplied fluid pressure acting on said other additive area.

Claim 12

A control valve according to claim 6, wherein said first-named means comprises a switch actuating piston having opposed ends, one of said opposed ends being slidable in said housing and including extension means slidable in said passage means, said one opposed area being defined on said one opposed end, and said first-named additive area being defined 61 said extension means. --. A control valve according to claim 10, wherein said one centering means includes piston means slidable in said housing, the other of said opposed ends being slidable in piston means and extending coaxially therethrough, opposed portions on said piston means, said other additive area being defined on one of said opposed portions, abutment means on said housing for engagement with the other of said opposed portions, and other abutment means on said switch-actuating piston for engagement with said other opposed portions, said other opposed portion being urged toward engagement with said first-named and other abutment means in response to the other supplied fluid pressure acting on said other additive area.

Claim 13

A control valve comprising a housing having a pair of input chambers and another chamber therein, means for controlling pressure fluid communication between one of said input chambers and said other chamber and movable in said housing from a normal centered position toward opposed translated positions including a pair of opposed areas respectively subjected to the fluid pressures in said input chambers, and an additive area subjected to the fluid pressure in said other chamber which is proportional to the fluid pressure in said one chamber and additive to one of said opposed areas, said means being urged in one directing againSt fluid pressure in the other of said input chambers acting on the other of said opposed areas in response to the fluid pressure in said one input chamber and the proportional fluid pressure in said other chamber respectively acting on said one opposed area and said additive area toward a translated position in said housing establishing equalizing pressure fluid communication between said one input chamber and said other chamber, and only a single centering means movable in said other input chamber for engagement with said housing and with said first-named means for urging said first-named means toward its centered position including another additive area subjected only to the fluid pressure in said other input chamber and additive to said other opposed area, said single centering means being urged toward engagement with said housing and said first-named means to oppose movement thereof from its centered position to its translated position in the one direction in response to the fluid pressure in said other input chamber acting on said other additive area.

Claim 14

A control valve comprising a housing having a pair of input chambers and another chamber therein, means for controlling pressure fluid communication between one of said input chambers and said other chamber and movable in said housing from a normal centered position toward opposed translated positions including a pair of opposed areas respectively subjected to the fluid pressures in said input chambers, and an additive area subjected to the fluid pressure in said other chamber which is proportional to the fluid pressure in said one chamber and additive to one of said opposed areas, said means being urged in one directing againSt fluid pressure in the other of said input chambers acting on the other of said opposed areas in response to the fluid pressure in said one input chamber and the proportional fluid pressure in said other chamber respectively acting on said one opposed area and said additive area toward a translated position in said housing establishing equalizing pressure fluid communication between said one input chamber and said other chamber, and only a single centering means movable in said other input chamber for engagement with said housing and with said first-named means for urging said first-named means toward its centered position including another additive area subjected only to the fluid pressure in said other input chamber and additive to said other opposed area, said single centering means being urged toward engagement with said housing and said first-named means to oppose movement thereof from its centered position to its translated position in the one direction in response to the fluid pressure in said other input chamber acting on said other additive area.

Claim 15

A control valve comprising a housing having three ports therein, means subjected to fluid pressures at said three ports and movable in said housing between a normally centered position and opposed translated positions for controlling pressure fluid communication between two of said ports, a pair of opposed areas on said first-named means, one of said opposed areas being subjected to the fluid pressure at said third port and the other of said opposed areas being subjected to the fluid pressure at one of said two ports, an additive area on said first-named means additive to said other opposed area and subjected to the fluid pressure at the other of said two ports proportional to the fluid pressure at said one of said two ports, said means being urged in one direction against fluid pressure at said third port acting on said one opposed area in response to fluid pressure at said one of said two ports acting on said other opposed area and fluid pressure at said other of said two ports proportional to that at said one of said two ports acting on said additive area, respectively, toward a translated position in said housing establishing equalizing pressure fluid communication between said two ports when the fluid pressure at one of said one and other of said two ports exceeds that at said third port by a predetermined value, only a single centering means movable in said housing for engagement with said housing and said first named means, and another additive area on said single centering means additive to said one opposed area and subjected to the fluid pressure at said third port, said single centering means being urged in response to the fluid pressure at said third port acting on said other additive area toward engagement with said housing and said first-named means to oppose movement of said first-named means in the one direction toward the displaced position thereof when the fluid pressure at said one of said one and other of said two ports in excess of that at said third port is lees than the predetermined value.

Claim 16

A control valve comprising a housing having three ports therein, means subjected to fluid pressures at said three ports and movable in said housing between a normally centered position and opposed translated positions for controlling pressure fluid communication between two of said ports, a pair of opposed areas on said first-named means, one of said opposed areas being subjected to the fluid pressure at said third port and the other of said opposed areas being subjected to the fluid pressure at one of said two ports, an additive area on said first-named means additive to said other opposed area and subjected to the fluid pressure at the other of said two ports proportional to the fluid pressure at said one of said two ports, said means being urged in one direction against fluid pressure at said third port acting on said one opposed area in response to fluid pressure at said one of said two ports acting on said other opposed area and fluid pressure at said other of said two ports proportional to that at said one of said two ports acting on said additive area, respectively, toward a translated position in said housing establishing equalizing pressure fluid communication between said two ports when the fluid pressure at one of said one and other of said two ports exceeds that at said third port by a predetermined value, only a single centering means movable in said housing for engagement with said housing and said first named means, and another additive area on said single centering means additive to said one opposed area and subjected to the fluid pressure at said third port, said single centering means being urged in response to the fluid pressure at said third port acting on said other additive area toward engagement with said housing and said first-named means to oppose movement of said first-named means in the one direction toward the displaced position thereof when the fluid pressure at said one of said one and other of said two ports in excess of that at said third port is lees than the predetermined value.

Claim 17

A control valve according to claim 13, wherein said one and other opposed areas are substantially equal, and said other additive area is greater than said first-named additive area.

Claim 18

A control valve according to claim 13, comprising passage means in said housing connected between said two ports, said first-named means including valve means movable in said passage means between positions respectively interrupting and establishing pressure fluid communication therethrough between said two ports, said valve means being movable toward its pressure fluid communication establishing position upon the movement of said first-named means in the one direction toward its translated position.

Claim 19

A control valve according to claim 13, comprising passage means in said housing connected between said two ports, said first-named means including extension means movable in said passage means, means in said pasSage means defining a valve seat, means on said extension means defining valve means movable between a position in sealing engagement with said valve seat to interrupt pressure fluid communication through said passage means between said ports and a position displaced from sealing engagement with said valve seat to establish pressure fluid communication through said passage means between said two ports, said valve means being movable toward its displaced position in concert with the movement of said first-named means in the one direction toward its translated position.

Claim 20

A control valve according to claim 16, wherein said first-named means comprises first piston means having opposed portions, one of said opposed portions being slidable in said housing, said extension means being connected with said one opposed portion and slidable in said passage means, said single centering means including second piston means slidable in said housing, and opposed ends on said second piston means, the other of said opposed portions being slidable in said second piston means and extending through said opposed ends thereof, said one and other opposed areas being on said other and said one opposed portions, respectively, said first-named additive area being on said extension means and subjected to the proportional fluid pressure at the other of said two ports when said valve means is sealably engaged with said valve seat, said other additive area being on one of said opposed ends of said second piston means, first and second abutment means on said housing and said first piston means for engagement with the other of said opposed ends, said other opposed end being urged toward engagement with said first and second abutment means in response to the fluid pressure at said third port acting on said other additive area.

Claim 21

A control valve comprising a housing having a bore therein, first and second stepped counterbores in said housing aligned with one end of said bore, a shoulder on said housing between said first and second counterbores, first, second and third fluid pressure ports in said housing respectively connected with said bore, said first counterbore, and said second counterbore, first piston means slidable in said second counterbore and including first and second opposed end portions, a first effective area defined on said first end portion for subjection to the fluid pressure at said third port, said second end portion being engageable with said shoulder, and another bore in said first piston means between said first and second end portions, second piston means movable in said housing between a normally centered position and opposed translated positions including third and fourth opposed end portions, said third end portion being slidable in said other bore and extending therethrough into said second counterbore, abutment means between said third and fourth end portions for engagement with said second end portion, the fluid pressure at said third port acting on said first area to normally urge said second end portion toward engagement with said housing shoulder and said abutment means, a second effective area on said third end portion additive to said first area and subjected to the fluid pressure at said third port, a third effective area on said fourth end portion opposed to said second area and subjected to the fluid pressure at said second port, extension means on said fourth end portion having a free end portion slidable in said first named bore, means on said free end portion defining valve means movable between a position in sealing engagement with said first-named bore to interrupt pressure fluid communication therethrough between said first and second ports and a position displaced from sealing engagement with said first-named bore to establish pressure fluid communication therethrough between said first and second ports, and a fourth effective area on said free end portion and subjected to fluid pressure at said first port which is predeterminately proportional to the fluId pressure at said second port when said valve means is in its sealing position, said first and second piston means being concertedly urged toward one of the translated positions of said second piston means against the fluid pressure at said third port acting on said first and second areas in response to the fluid pressure at said second port and the proportional fluid pressure at said first port respectively acting on said third and fourth areas to move said valve means toward its displaced position establishing equalizing pressure fluid communication between said first and second ports when the magnitude of the fluid pressure at said second port exceeds that of the fluid pressure at said third port by a predetermined value, and said second end portion of said first piston means being normally urged toward engagement with said housing shoulder and abutment means in response to the fluid pressure at said third port acting on said first area to oppose movement of said second piston means from its centered position toward its one translated position when the differential between the magnitude of the fluid pressure at said second port in excess of that of the fluid pressure at said third port is less than the predetermined value.

Claim 22

A control valve comprising a housing having a bore therein, first and second stepped counterbores in said housing aligned with one end of said bore, a shoulder on said housing between said first and second counterbores, first, second and third fluid pressure ports in said housing respectively connected with said bore, said first counterbore, and said second counterbore, first piston means slidable in said second counterbore and including first and second opposed end portions, a first effective area defined on said first end portion for subjection to the fluid pressure at said third port, said second end portion being engageable with said shoulder, and another bore in said first piston means between said first and second end portions, second piston means movable in said housing between a normally centered position and opposed translated positions including third and fourth opposed end portions, said third end portion being slidable in said other bore and extending therethrough into said second counterbore, abutment means between said third and fourth end portions for engagement with said second end portion, the fluid pressure at said third port acting on said first area to normally urge said second end portion toward engagement with said housing shoulder and said abutment means, a second effective area on said third end portion additive to said first area and subjected to the fluid pressure at said third port, a third effective area on said fourth end portion opposed to said second area and subjected to the fluid pressure at said second port, extension means on said fourth end portion having a free end portion slidable in said first named bore, means on said free end portion defining valve means movable between a position in sealing engagement with said first-named bore to interrupt pressure fluid communication therethrough between said first and second ports and a position displaced from sealing engagement with said first-named bore to establish pressure fluid communication therethrough between said first and second ports, and a fourth effective area on said free end portion and subjected to fluid pressure at said first port which is predeterminately proportional to the fluId pressure at said second port when said valve means is in its sealing position, said first and second piston means being concertedly urged toward one of the translated positions of said second piston means against the fluid pressure at said third port acting on said first and second areas in response to the fluid pressure at said second port and the proportional fluid pressure at said first port respectively acting on said third and fourth areas to move said valve means toward its displaced position establishing equalizing pressure fluid communication between said first and second ports when the magnitude of the fluid pressure at said second port exceeds that of the fluid pressure at said third port by a predetermined value, and said second end portion of said first piston means being normally urged toward engagement with said housing shoulder and abutment means in response to the fluid pressure at said third port acting on said first area to oppose movement of said second piston means from its centered position toward its one translated position when the differential between the magnitude of the fluid pressure at said second port in excess of that of the fluid pressure at said third port is less than the predetermined value.