Pressure compensating valve mechanism

Claim 2

A fluid flow controlling valve mechanism having a body with an inlet and an outlet and feeder and feedback ports all opening to a bore containing a fluid pressure responsive valve plunger, means to impose the pressure of fluid at the inlet upon a first surface of the plunger to urge it in one axial direction toward a normal position at which pressure fluid entering the bore from the inlet flows to the outlet in bypass relation to the feeder port, and means by which the pressure of fluid at the feedback port can be imposed upon a second surface of the plunger to move it in the opposite axial direction toward a feed position compelling inlet fluid to flow to the feeder port, characterized by: A. a strong primary spring connected with the plunger to resist movement thereof in said one axial direction, out of its feed position; B. a weaker secondary spring for the plunger; C. and means connected with the secondary spring and rendered operative by the plunger in the normal position of the latter for effecting imposition of secondary spring force upon the plunger in opposition to the force of the primary spring to thus enable the plunger to be held in its normal position by inlet fluid at substantially low pressure.

Claim 3

The fluid flow controlling valve mechanism of claim 1 further characterized by: A. said means which is connected with the secondary spring comprising a piston which is movable in one direction from one position to another position at which the secondary spring is ineffective to oppose the primary spring; B. and means for effecting motion of the piston to said other position thereof in consequence of rise in fluid pressure at one of said ports.

Claim 4

The fluid flow controlling valve mechanism of claim 1, wherein the piston is confined between the primary and secondary springs and can be held in said one position thereof by the primary spring.

Claim 5

The fluid flow controlling valve mechanism of claim 3, wherein pressure of fluid at the feedback port acts upon the piston to moVe the same to said other position thereof at which it effects relaxation of the secondary spring.

Claim 6

The fluid flow controlling valve mechanism of claim 1, further characterized by: A. said means which is connected with the secondary spring comprising a piston confined between said springs and movable axially toward said second surface on the plunger to relax the secondary spring; B. and means for effecting movement of the piston axially toward said second surface on the plunger in consequence of rise in pressure at the feedback port.

Claim 7

The fluid flow controlling valve mechanism of claim 5, further characterized by: A. the secondary spring being confined in the bottom portion of a cylinder in which said piston operates; B. and means providing a passageway communicating the bottom portion of said cylinder with the feedback port.

Claim 8

The fluid flow controlling valve mechanism of claim 6, further characterized by: A. the plunger having a well in its end adjacent to said piston, in which the primary spring is received; B. the feedback port opening to said well; C. and the piston having an axial passage therethrough communicating said well with the bottom of the cylinder.

Claim 9

The fluid flow controlling valve mechanism of claim 7, further characterized by: A. the opposite ends of the piston being subjected to the pressure of feedback fluid in said well and in the bottom portion of the cylinder; B. and the cylinder and piston having correspondingly larger diameter portions at the end of the piston remote from the plunger.

Claim 10

The fluid flow controlling valve mechanism of claim 1, further characterized by: A. said springs being connected in series with the plunger whereby the force which they exert thereon in its normal position is equal to the product of their ratings divided by the sum thereof; B. and said means which is connected with the secondary spring being operable in the feed position of the plunger, in response to pressure of fluid at said feed back port, for substantially nullifying the effect of said secondary spring upon the plunger.

Claim 11

A pressure compensating valve mechanism having inlet, outlet, feeder and feedback ports all opening to a bore containing a fluid pressure responsive valve plunger, said mechanism being of the type having provision for delivery of inlet fluid to one end of the bore where it can exert force on the plunger and normally hold it in a neutral position at which inlet fluid can flow to the outlet in bypass relation to the feeder port, and wherein the plunger is movable to an operating position limiting said bypass flow and diverting inlet fluid to the feeder port, characterized by: A. means opening to the other end of the bore providing a cylinder coaxial with the bore; B. a piston movable axially in the cylinder; C. a primary compression spring reacting between the piston and the plunger and operable in the neutral position of the latter to hold the piston in engagement with an abutment in the outer end of the cylinder; D. a secondary compression spring confined in said outer end of the cylinder and normally held in a loaded condition by the piston under the force which the primary spring exerts thereon in said neutral position of the plunger, whereby the force which the primary spring exerts upon the plunger tending to move it toward its operating position is substantially diminished except at times when the secondary spring is relaxed; E. and means communicating said outer end of the cylinder with the feedback port so that the force which feedback fluid exerts upon the piston will move the same in the direction to relax the secondary spring.

Claim 12

A pressure compensating valve mechanism having inlet, outlet, feeder and feedback ports all opening to a bore containing a fluid pressure responsive valve plunger, said mechanism being of the type having provision for delivery of inlet fluid to one end of the bore where it can exert force on the plunger and normally hold it in a neutral position at which inlet fluid can flow to the outlet in bypass relation to the feeder port, and wherein the plunger is movable to an operating position limiting said bypass flow and diverting inlet fluid to the feeder port, characterized by: A. means opening to the other end of the bore providing a cylinder coaxial with the bore; B. a piston movable axially in the cylinder; C. a primary compression spring reacting between the piston and the plunger and operable in the neutral position of the latter to hold the piston in engagement with an abutment in the outer end of the cylinder; D. a secondary compression spring confined in said outer end of the cylinder and normally held in a loaded condition by the piston under the force which the primary spring exerts thereon in said neutral position of the plunger, whereby the force which the primary spring exerts upon the plunger tending to move it toward its operating position is substantially diminished except at times when the secondary spring is relaxed; E. and means communicating said outer end of the cylinder with the feedback port so that the force which feedback fluid exerts upon the piston will move the same in the direction to relax the secondary spring.

Claim 13

A pressure compensating valve mechanism having a plunger movable axially in a bore in the body of the mechanism and having means to impose the pressure of fluid at an inlet upon a first surface of the plunger to urge it axially in one direction in thE bore toward a normal position at which fluid entering the bore from the inlet flows to an outlet in bypass relation to a feeder port, and having a feedback port by which the pressure of feedback fluid can be imposed upon a second surface of the plunger to move it in the opposite axial direction toward a feed position compelling inlet fluid to flow to the feeder port, characterized by: A. a primary plunger spring connected with the plunger to substantially strongly resist movement thereof in said one direction out of its feed position; B. a secondary plunger spring which is weaker than the primary plunger spring; C. means defining a cylinder; D. a piston in the cylinder connected with the secondary spring and operable in said normal position of the plunger to render the secondary spring effective to impose force upon the plunger in opposition to the force of the primary spring providing the piston is in one axial position at which it engages an abutment on the body, said piston being movable away from said abutment to a second position at which it renders the secondary spring ineffective; E. and means for effecting movement of the piston to its said second position in consequence of rise in fluid pressure at one of said ports.

Claim 14

A pressure compensating valve mechanism having a plunger movable axially in a bore in the body of the mechanism and having means to impose the pressure of fluid at an inlet upon a first surface of the plunger to urge it axially in one direction in thE bore toward a normal position at which fluid entering the bore from the inlet flows to an outlet in bypass relation to a feeder port, and having a feedback port by which the pressure of feedback fluid can be imposed upon a second surface of the plunger to move it in the opposite axial direction toward a feed position compelling inlet fluid to flow to the feeder port, characterized by: A. a primary plunger spring connected with the plunger to substantially strongly resist movement thereof in said one direction out of its feed position; B. a secondary plunger spring which is weaker than the primary plunger spring; C. means defining a cylinder; D. a piston in the cylinder connected with the secondary spring and operable in said normal position of the plunger to render the secondary spring effective to impose force upon the plunger in opposition to the force of the primary spring providing the piston is in one axial position at which it engages an abutment on the body, said piston being movable away from said abutment to a second position at which it renders the secondary spring ineffective; E. and means for effecting movement of the piston to its said second position in consequence of rise in fluid pressure at one of said ports.

Claim 15

The pressure compensating valve mechanism of claim 11 further characterized by: A. said primary and secondary springs being connected with the plunger at opposite ends thereof; B. and said piston being movable to its said second position in consequence of rise in fluid pressure at the feeder port.

Claim 16

A pressure compensating valve mechanism having a plunger operable in a feed position to regulate the rate at which pump fluid flows from an inlet to a feeder port in accordance with variations in the pressure differential between the feeder port and a feedback port, and wherein the plunger is held in a normal position displaced from its feed position under force which inlet fluid exerts upon one surface thereof to allow inlet fluid to flow to an outlet in bypass relation to the feeder port, characterized by: A. a strong primary plunger spring; B. a weaker secondary plunger spring; C. means connecting the primary spring with the plunger so that the primary spring will substantially strongly resist movement of the plunger out of its feed position; D. means connecting the secondary spring with the plunger; E. said last named means being rendered operative by the plunger, in said normal position thereof, to impose the force of the secondary spring upon the plunger in offsetting relation to the force of the primary spring; F. and said last named means being rendered operative in consequence of fluid pressure at one of said ports, in the feed position of the plunger, to nullify said force offsetting effect of the secondary spring upon the plunger.

Claim 17

A pressure compensating valve mechanism having a plunger operable in a feed position to regulate the rate at which pump fluid flows from an inlet to a feeder port in accordance with variations in the pressure differential between the feeder port and a feedback port, and wherein the plunger is held in a normal position displaced from its feed position under force which inlet fluid exerts upon one surface thereof to allow inlet fluid to flow to an outlet in bypass relation to the feeder port, characterized by: A. a strong primary plunger spring; B. a weaker secondary plunger spring; C. means connecting the primary spring with the plunger so that the primary spring will substantially strongly resist movement of the plunger out of its feed position; D. means connecting the secondary spring with the plunger; E. said last named means being rendered operative by the plunger, in said normal position thereof, to impose the force of the secondary spring upon the plunger in offsetting relation to the force of the primary spring; F. and said last named means being rendered operative in consequence of fluid pressure at one of said ports, in the feed position of the plunger, to nullify said force offsetting effect of the secondary spring upon the plunger.