Pilot operated control valve

Claim 2

In a hydraulic valve for directional control of a hydraulic mOtor, a valve body, the body defining a pair of axial bores each reciprocably housing a spool therein, the body further defining an inlet passage and an outlet passage, each intersecting the bores in axially spaced apart relation, and a pair of work ports for communication with the opposite sides of the hydraulic motor; the spools being movable between a normal spring biased position blocking communication of the inlet and outlet passages with the work ports and first and second positions for respectively communicating the supply passage to one of the work ports and communicating the other work port with the outlet passage, a first actuating means for moving one of the spools to its first position, a second actuating means associated with the other spool responsive to displaced fluid flow from the motor to move the other of the spools to a position for unrestricted communication of the other work port with the outlet passage, the second actuating means being further responsive to flow of displaced fluid from the motor in excess of a predetermined amount to move the other spool out of its second position and progressively restrict communication between the work port and the outlet passage.

Claim 3

The valve of claim 1 wherein the first actuating means comprises a pilot actuating chamber assoicated with each spool, metering means being associated with the actuating chambers for metering pilot fluid thereinto at a rate proportional to the desired rate of flow of the pressure fluid from the supply passage to one of the work ports.

Claim 4

The valve of claim 2 wherein the metering means of each actuating chamber is in communication with the respective work port to combine the metered pilot fluid with the pressure fluid communicated from the supply passage for delivery to the respective work port.

Claim 5

The valve of claim 1 wherein each of the spools is cylindrical and is of substantially constant outer diameter throughout its axial length, each spool also having a central axial chamber opening unrestrictedly to one end thereof for communication with the respective work port, and each spool also having axially spaced apart radial ports for communication between the chamber and the spool bore, the axial spacing of the radial ports being different than the axial spacing for the intersections of the inlet and outlet passages with the bore so that when the spool is in its normal spring biased position, communication between the chamber and the passages is blocked.

Claim 6

The valve of claim 4 wherein the actuating means for each spool includes a restrictive orifice arranged at the other end of the spool from its unrestricted opening to the respective work port.

Claim 7

A pilot operable control valve for regulating a double-acting fluid motor comprising a valve body forming two axial bores, the valve body also forming inlet and outlet passages in axially spaced apart communication with the bores, a pilot fluid inlet port being formed in one end of each bore and a work port being formed in the other end of each bore for respective communication with the motor, a spool reciprocably arranged in each bore, each spool having an axially formed chamber opening at one end into its bore adjacent the respective work port, each spool also forming a restrictive orifice at the other end thereof for communicating its axial chamber with its bore adjacent the respective pilot fluid inlet port, each spool also forming axially spaced apart radial ports for communicating the axial chamber with the spool bore, the axial spacing for the radial ports being less than the axial spacing between the inlet and outlet passages along the bore, and means for normally urging each spool into a centered position where its radial ports are between and out of communication with the inlet and outlet passages, the outlet passage being in communication with each bore between the inlet passage and the work port, each spool being movable toward the respective pilot fluid inlet port from its centered position to place one of its radial ports in communication with the outlet passage, each spool being further movable toward the pilot fluid inlet port to place its one radial port out of communication with the outlet passage.

Claim 8

A pilot operable control valve for regulating a double-acting fluid motor comprising a valve body forming two axial bores, the valve body also forming inlet and outlet passages in axially spaced apart communication with the bores, a pilot fluid inlet port being formed in one end of each bore and a work port being formed in the other end of each bore for respective communication with the motor, a spool reciprocably arranged in each bore, each spool having an axially formed chamber opening at one end into its bore adjacent the respective work port, each spool also forming a restrictive orifice at the other end thereof for communicating its axial chamber with its bore adjacent the respective pilot fluid inlet port, each spool also forming axially spaced apart radial ports for communicating the axial chamber with the spool bore, the axial spacing for the radial ports being less than the axial spacing between the inlet and outlet passages along the bore, and means for normally urging each spool into a centered position where its radial ports are between and out of communication with the inlet and outlet passages, the outlet passage being in communication with each bore between the inlet passage and the work port, each spool being movable toward the respective pilot fluid inlet port from its centered position to place one of its radial ports in communication with the outlet passage, each spool being further movable toward the pilot fluid inlet port to place its one radial port out of communication with the outlet passage.

Claim 9

A pilot operable control valve for regulating an extendible and retractable fluid motor, comprising a valve body forming an axial bore, inlet and outlet passages in axially spaced apart communication with the bore, a pilot fluid inlet port in one end of the bore and a work port in the other end of the bore for communication with the motor, a spool reciprocably arranged in the bore, the spool having an axially formed chamber opening at one end into the bore adjacent the work port and a restrictive orifice at the other end of the spool in communication between the axial chamber and the pilot fluid inlet port, the spool also having axially spaced apart radial ports situated between the inlet and outlet passages when the spool is in a centered position in the bore, and means for normally urging the spool into its centered position, the outlet passage being in communication with the bore between the inlet passage and the work port, the spool being movable from its centered position to initially position one of the radial ports in communication with the outlet passage and then to move the one port out of communication with the outlet passage.

Claim 10

A pilot operable control valve for regulating an extendible and retractable fluid motor, comprising a valve body forming an axial bore, inlet and outlet passages in axially spaced apart communication with the bore, a pilot fluid inlet port in one end of the bore and a work port in the other end of the bore for communication with the motor, a spool reciprocably arranged in the bore, the spool having an axially formed chamber opening at one end into the bore adjacent the work port and a restrictive orifice at the other end of the spool in communication between the axial chamber and the pilot fluid inlet port, the spool also having axially spaced apart radial ports situated between the inlet and outlet passages when the spool is in a centered position in the bore, and means for normally urging the spool into its centered position, the outlet passage being in communication with the bore between the inlet passage and the work port, the spool being movable from its centered position to initially position one of the radial ports in communication with the outlet passage and then to move the one port out of communication with the outlet passage.