Pressure control device for a hydraulic circuit

Claim 2

A pressure control device for sequentially setting a plurality of hydraulic pressures in a hydraulic supply line to a multi-cycle hydraulic consumer, comprising: A. A pressure balance valve which comprises:

Claim 3

a central pump channel and a central return channel which are interconnected by a throttle passage, said pump channel being in hydraulic communication at pump pressure with a pump and with said hydraulic consumer and said return channel being in hydraulic communication with a reservoir for said pump,

Claim 4

a central pump channel and a central return channel which are interconnected by a throttle passage, said pump channel being in hydraulic communication at pump pressure with a pump and with said hydraulic consumer and said return channel being in hydraulic communication with a reservoir for said pump,

Claim 5

a housing, disposed in said pressure space, which is in axial alignment with said pressure balance slide and comprises an interior space in hydraulic communication with said reservoir,

Claim 6

a housing, disposed in said pressure space, which is in axial alignment with said pressure balance slide and comprises an interior space in hydraulic communication with said reservoir,

Claim 7

a pressure control slide, having a pressure end and an armature end, which is axially slideable within a pressure control cylinder,

Claim 8

a pressure control slide, having a pressure end and an armature end, which is axially slideable within a pressure control cylinder,

Claim 9

a pressure balance slide, which is adapted for sliding movement past said throttle passage to provide selective narrowing thereof between fully open and fully closed, comprising a spring-loaded end within a pressure space and a pump-loaded end,

Claim 10

a pressure balance slide, which is adapted for sliding movement past said throttle passage to provide selective narrowing thereof between fully open and fully closed, comprising a spring-loaded end within a pressure space and a pump-loaded end,

Claim 11

The pressure control device of claim 1 wherein said control plunger and said valve means are connected with a spring.

Claim 12

a valve seat in said housing, having an adjusting bore therein which provides hydraulic communication between said pressure space and said interior space,

Claim 13

a valve seat in said housing, having an adjusting bore therein which provides hydraulic communication between said pressure space and said interior space,

Claim 14

control bore means providing hydraulic communication between said pressure chamber and said pressure control cylinder,

Claim 15

control bore means providing hydraulic communication between said pressure chamber and said pressure control cylinder,

Claim 16

feed bore means providing pressurized hydraulic fluid to said pressure control cylinder,

Claim 17

feed bore means providing pressurized hydraulic fluid to said pressure control cylinder,

Claim 18

valve means adapted to press onto said seat and selectively close said adjusting bore, whereby the rate of flow of hydraulic fluid through said adjusting bore is selectively adjustable in relation to said selected rate of flow of hydraulic fluid through said throttle means,

Claim 19

valve means adapted to press onto said seat and selectively close said adjusting bore, whereby the rate of flow of hydraulic fluid through said adjusting bore is selectively adjustable in relation to said selected rate of flow of hydraulic fluid through said throttle means,

Claim 20

The pressure control device of claim 1 wherein said bore means supplying hydraulic fluid to said pump-loaded end is connected to said pump channel.

Claim 21

bore means for supplying hydraulic fluid at pump pressure to said pump-loaded end,

Claim 22

bore means for supplying hydraulic fluid at pump pressure to said pump-loaded end,

Claim 23

bore means, having a throttle means therein, for supplying hydraulic fluid at a selected rate of flow to said pressure space; and

Claim 24

bore means, having a throttle means therein, for supplying hydraulic fluid at a selected rate of flow to said pressure space; and

Claim 25

The pressure control device of claim 3 wherein said bore means passes through said pressure balance slide.

Claim 26

a control plunger, having a pressure chamber at one end thereof, which is connected to said valve means within said interior space and is adapted to be moved axially toward said seat by pressure in said pressure chamber; and C. an electrically controlled pressure-setting means which comprises:

Claim 27

a control plunger, having a pressure chamber at one end thereof, which is connected to said valve means within said interior space and is adapted to be moved axially toward said seat by pressure in said pressure chamber; and C. an electrically controlled pressure-setting means which comprises:

Claim 28

return bore means providing hydraulic communication between said pressure control cylinder and said reservoir,

Claim 29

return bore means providing hydraulic communication between said pressure control cylinder and said reservoir,

Claim 30

a control spring providing spring pressure upon said pressure end,

Claim 31

a control spring providing spring pressure upon said pressure end,

Claim 32

The pressure control device of claim 4 wherein said bore means comprises, within said pressure balance slide, a radially disposed bore and an axially disposed bore which are mutually interconnected.

Claim 33

a light spring which is adapted to exert pressure upon said spring-loaded end; B. a pressure-limiting valve assembly which comprises:

Claim 34

a light spring which is adapted to exert pressure upon said spring-loaded end; B. a pressure-limiting valve assembly which comprises:

Claim 35

The pressure control device of claim 1 wherein said bore means supplying hydraulic fluid to said pump-loaded end is connected directly to said pump.

Claim 36

an armature attached to said armature end, and

Claim 37

an armature attached to said armature end, and

Claim 38

The pressure control device of claim 1 wherein said control bore means comprises a throttle means, whereby the switching speed of said control plunger can be set.

Claim 39

an electric magnet which provides a selected magnetic flux, when energized by a selected electrical current, that moves said armature towards said control spring to establish hydraulic communication between said control bore means and said feed bore means and that, when unenergized, permits said armature to be moved by said control spring to establish hydraulic communication between said control bore means and said return bore means, whereby pressure is reduced in said pressure chamber and flow occurs through said adjusting bore.

Claim 40

an electric magnet which provides a selected magnetic flux, when energized by a selected electrical current, that moves said armature towards said control spring to establish hydraulic communication between said control bore means and said feed bore means and that, when unenergized, permits said armature to be moved by said control spring to establish hydraulic communication between said control bore means and said return bore means, whereby pressure is reduced in said pressure chamber and flow occurs through said adjusting bore.

Claim 41

The pressure control device of claim 1 wherein said control bore means is in hydraulic communication with said pressure end of said pressure control slide, whereby pressurized hydraulic fluid augments the force exerted by said control spring.

Claim 42

The pressure control device of claim 1 wherein said feed bore means is connected to said pump channel.

Claim 43

The pressure control device of claim 1 wHerein said feed bore means is connected to said pump.

Claim 44

In a pressure-control device for selectively setting a maximum operating pressure in a hydraulic circuit in which said device includes: a pressure balance valve, having a pressure-balance slide controlling a throttle passage interconnecting a pump channel and a return channel to the reservoir for said pump, said slide being moved to open said passage by balance pressure at one end thereof, and a pressure-limiting valve assembly, having a control plunger pressurized at one end thereof by an electrically reduced pressure fed through a control bore, said plunger being moved to open an auxilliary bore for lowering said balance pressure when said electrically reduced pressure is insufficient, the improvement comprising the formation of said electrically reduced pressure in said control bore by movement of a two-way control slide which: A. operates between a feed bore, said control bore, and a return bore to said reservoir by means of an electric magnet moving an armature in response to a selected electrical current, said control bore having no other outlet than said return bore; B. is loaded at one end thereof by said electrically reduced pressure; and C. is attached at the other end thereof to said armature.

Claim 45

In a pressure-control device for selectively setting a maximum operating pressure in a hydraulic circuit in which said device includes: a pressure balance valve, having a pressure-balance slide controlling a throttle passage interconnecting a pump channel and a return channel to the reservoir for said pump, said slide being moved to open said passage by balance pressure at one end thereof, and a pressure-limiting valve assembly, having a control plunger pressurized at one end thereof by an electrically reduced pressure fed through a control bore, said plunger being moved to open an auxilliary bore for lowering said balance pressure when said electrically reduced pressure is insufficient, the improvement comprising the formation of said electrically reduced pressure in said control bore by movement of a two-way control slide which: A. operates between a feed bore, said control bore, and a return bore to said reservoir by means of an electric magnet moving an armature in response to a selected electrical current, said control bore having no other outlet than said return bore; B. is loaded at one end thereof by said electrically reduced pressure; and C. is attached at the other end thereof to said armature.