US3575000A — High pressure implement hydraulic circuit

Claim 1

Independent Claim 101 words

A low-pressure hydraulic control circuit for controlling at least two high-pressure work output systems including at least two selectively actuatable control valves, conduit means connecting each of said control valves to a variable displacement pump whereby flow in either work output system may be controlled by said two selectively actuatable control valves, a separate directional valve in each of said high-pressure work output systems, and means separately connecting each of said selectively actuatable control valves with said directional valve in its associated work output system whereby flow in either of said work output systems can be controlled in direction and amount.

Claim 2

Dependent Claim 101 words

A low-pressure hydraulic control circuit for controlling at least two high-pressure work output systems including at least two selectively actuatable control valves, conduit means connecting each of said control valves to a variable displacement pump whereby flow in either work output system may be controlled by said two selectively actuatable control valves, a separate directional valve in each of said high-pressure work output systems, and means separately connecting each of said selectively actuatable control valves with said directional valve in its associated work output system whereby flow in either of said work output systems can be controlled in direction and amount.

Claim 3

Dependent Claim 60 words

The circuit of claim 1 including a priority valve in the means connecting the control valves to the variable displacement pump, and means in the priority valve for providing that a control signal from one of the control valves shall always take priority over the control signal of the other control valve in controlling the amount of work output flow.

Claim 4

Dependent Claim 61 words

The circuit of claim 2 wherein the priority valve has a spool means therein, means biasing the spool to a first position, means responsive to an actuation signal from the one control valve for actuating the spool to a second position, and means responsive to an actuation signal from the other control valve for actuating the spool to a third position.

Claim 5

Dependent Claim 41 words

The circuit of claim 3 wherein the actuating means comprise pistons of unequal areas whereby equal actuation signals from the control valves cause the larger area piston to override any force exerted by the smaller area piston against the spool means.

Claim 6

Dependent Claim 51 words

The circuit of claim 3 wherein the actuating means comprise axially aligned pistons of unequal surface area, the larger piston acting against one end of the spool means and the smaller piston acting against the larger piston so as to exert force on the same one end of the spool means.

Claim 7

Dependent Claim 64 words

The circuit of claim 5 wherein means deliver fluid to the surface areas of the pistons in response to the actuation signals of the control valves, and the relative sizes of the piston surface areas are such that equal fluid pressure delivered to both pistons causes the larger piston to move the spool means past the second position and on to the third position.

Claim 8

Dependent Claim 43 words

The circuit of claim 1 including means associated with one of the directional valves denying work output flow to the other directional valve when the one directional valve is actuated by its control valve to provide a work output in a first direction.

Claim 9

Dependent Claim 42 words

The circuit of claim 8 including means associated with the one directional valve providing work output flow to the other directional valve when the one directional valve is actuated by its control valve to provide a work output in a second direction.

Claim 10

Dependent Claim 68 words

The circuit of claim 1 including valve means in the means connecting each control valve to each directional valve, said valve means selectively actuated by the control valve, means connecting said output flow of the variable displacement pump to each valve means, and actuatable means in the directional valve selectively positioned to produce the required work direction in response to a resultant output flow through the valve means.

Claim 11

Dependent Claim 135 words

A hydraulic circuit wherein a low-pressure system is employed for controlling a high-pressure fluid work output system including a selectively actuatable control valve connected to a source of low-pressure fluid, a variable displacement pump having a high-pressure variable flow output and a control servo for adjusting said high-pressure variable flow output, conduit means connecting said control valve and said control servo operable to control said variable displacement pump as a function of said control valve by fluid pressure in said conduit means, a directional valve having its output connected to said work output system and its inlet connected to said high-pressure variable flow output of said variable displacement pump, and fluid actuated means connected between said control valve and directional valve whereby both the high-pressure flow to and direction of said work output is controlled.

Claim 12

Dependent Claim 135 words

A hydraulic circuit wherein a low-pressure system is employed for controlling a high-pressure fluid work output system including a selectively actuatable control valve connected to a source of low-pressure fluid, a variable displacement pump having a high-pressure variable flow output and a control servo for adjusting said high-pressure variable flow output, conduit means connecting said control valve and said control servo operable to control said variable displacement pump as a function of said control valve by fluid pressure in said conduit means, a directional valve having its output connected to said work output system and its inlet connected to said high-pressure variable flow output of said variable displacement pump, and fluid actuated means connected between said control valve and directional valve whereby both the high-pressure flow to and direction of said work output is controlled.

Claim 13

Dependent Claim 112 words

The circuit of claim 10 including a first valve means and a second valve means in the means connecting the control valve to the directional valve, the first valve means actuated when the control valve is operated in a first direction and the second valve means actuated when the control valve is operated in a second direction, the first and second valve means operatively connected to the directional valve so that actuation of the first valve means causes the directional valve to provide a work output flow in a first direction and actuation of the second valve means causes the directional valve to provide a work output flow in a second direction.

Claim 14

Dependent Claim 59 words

The circuit of claim 11 including at least one check valve means in the directional valve, the check valve means being selectively relieved by actuation of either the first or second valve means so as to allow tHe work output flow of the variable displacement pump to flow through the directional valve in either the first or second direction.

Claim 15

Dependent Claim 53 words

The circuit of claim 11 including actuatable means, in the means connecting the control valve to the directional valve, actuated when the control valve is operated to a selected position, allowing the directional valve to be so conditioned as to allow external forces to motivate the machinery controlled by the work output system.

Claim 16

Dependent Claim 21 words

The circuit of claim 10 wherein the directional valve includes modulating means to reduce pressure surges in the work output system.

Claim 17

Dependent Claim 47 words

The circuit of claim 10 wherein the directional valve includes poppet means in its inlet preventing coupling the high-pressure variable displacement output of the variable displacement output of the variable displacement pump to the work output system until the pressure exceeds that in said work output system.

Claim 18

Dependent Claim 30 words

The circuit of claim 16 wherein the poppet means in the directional valve will close if the flow in the work output system exceeds that of the variable displacement pump.

Claim 19

Dependent Claim 38 words

The circuit of claim 10 wherein the fluid actuated means includes valve means whereby the directional valve will be positioned so that work output is not hydraulically locked when the control valve is placed in a float position.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-04-12	1974-10-12	1975-04-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-04-12	1978-10-12	1979-04-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-04-12	1982-10-12	1983-04-13	$7700.00	Window Closed / Lapsed

High pressure implement hydraulic circuit

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