US3628558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic control valve
Assignee: Deere and Co
•
Filing: 1970-09-02
•
Granted: 1971-12-21
•
Expires: 1990-09-02
Abstract
Abstract A hydraulic system has a pump, which supplies fluid pressure for both primary and secondary hydraulic functions. A hydraulic control valve is disposed in the system to shut off the fluid pressure supplied to the secondary hydraulic functions when the flow rate required by the hydraulic functions exceeds the pump capacity to cause a reduction in pressure below a predetermined value. The control valve also disconnects the secondary hydraulic function from the rest of the system when the secondary function generates surge pressures above a predetermined value and simultaneously connects the secondary function to the reservoir, so that the valve also functions as a check and relief valve for the secondary function. The valve further automatically connects the pump to the reservoir when the pump is driven at very low speeds and produces a very low-flow rate, such as during starting of the engine which drives the pump, to lessen the load on the starting motor.
Inventors
- 👤 James Melvin Bahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:46
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/022; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2559; Y10T137/2574; Y10T137/2579; Y10T137/2582; Y10T137/2587; Y10T137/2592; Y10T137/2605; Y10T137/2617; Y10T137/262
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
235 words
In a hydraulic system having a source of fluid pressure, a reservoir, and a plurality of hydraulic functions, including priority and nonpriority hydraulic functions, the improvement comprising: a valve body having a cylindrical valve bore with a first bore portion and a second bore portion having a smaller diameter than the first bore portion; first, second, third and fourth conduit means respectively connecting the valve bore to the fluid pressure source, at least one priority function, at least one nonpriority function and the reservoir; an axially slidable valve member having first and second diameter portions respectively conforming to and disposed within the first and second bore portions and axially slidable between a first position wherein it establishes fluid communication between the first conduit means and the second conduit means only, a second position wherein it established fluid cOmmunication between the first, second, and third conduit means only, and a third position wherein it establishes fluid communication between the third and fourth conduit means; a pressure-sensing passage means interconnecting the first and second bore portions on opposite sides of the valve member; and a spring means operatively engaging the valve member to bias it in the opposite direction from the net force exerted by the fluid pressure acting on the different diameter valve member portions, whereby the valve member shifts between its different positions in response to changes in fluid pressure acting on the valve member.
Claim 2
Dependent Claim
235 words
In a hydraulic system having a source of fluid pressure, a reservoir, and a plurality of hydraulic functions, including priority and nonpriority hydraulic functions, the improvement comprising: a valve body having a cylindrical valve bore with a first bore portion and a second bore portion having a smaller diameter than the first bore portion; first, second, third and fourth conduit means respectively connecting the valve bore to the fluid pressure source, at least one priority function, at least one nonpriority function and the reservoir; an axially slidable valve member having first and second diameter portions respectively conforming to and disposed within the first and second bore portions and axially slidable between a first position wherein it establishes fluid communication between the first conduit means and the second conduit means only, a second position wherein it established fluid cOmmunication between the first, second, and third conduit means only, and a third position wherein it establishes fluid communication between the third and fourth conduit means; a pressure-sensing passage means interconnecting the first and second bore portions on opposite sides of the valve member; and a spring means operatively engaging the valve member to bias it in the opposite direction from the net force exerted by the fluid pressure acting on the different diameter valve member portions, whereby the valve member shifts between its different positions in response to changes in fluid pressure acting on the valve member.
Claim 3
Dependent Claim
56 words
The invention defined in claim 1 wherein the valve member shifts to its first position when the fluid pressure falls below a first predetermined value, to its third position when the fluid pressure exceeds a second predetermined value, and shifts to its second position when the fluid pressure is between said first and second predetermined values.
Claim 4
Dependent Claim
16 words
The invention defined in claim 2 wherein the pressure-sensing passage means extends through the valve member.
Claim 5
Dependent Claim
21 words
The invention defined in claim 2 wherein the first, second, third and fourth conduit means communicates with the first bore portion.
Claim 6
Dependent Claim
53 words
The invention defined in claim 4 wherein the second, third and fourth conduit means are connected to the first bore portion at axially spaced intervals, and the first valve member portion has an annular recess about its periphery connecting the third and fourth conduit means in the third position of the valve member.
Claim 7
Dependent Claim
58 words
The invention defined in claim 5 wherein the passage means includes an orifice and the valve member is shiftable into a start-up position wherein it connects the first conduit means to the fourth conduit means through said passage means when the pressure acting on the valve member falls below a third predetermined value below said first predetermined value.
Claim 8
Dependent Claim
259 words
In a hydraulic system having a source of fluid pressure, a reservoir, and a plurality of hydraulic functions, including priority and nonpriority hydraulic functions, the improvement comprising: a valve body having a cylindrical valve bore with a first bore portion and a second portion having a smaller diameter than the first bore portion; first, second, third and fourth conduit means respectively connecting the valve bore to the fluid pressure source, at least one priority function, at least one nonpriority function and the reservoir; an axially slidable valve member having first and second diameter portions respectively, conforming to and disposed within the first and second bore portions and axially slidable between a first position wherein it establishes fluid communication between the first conduit means and the second conduit means only, a second position wherein it establishes fluid communication between the first, second, and third conduit means only, and a startup position wherein it connects the first conduit means to the fourth conduit means; a pressure-sensing passage means interconnecting the first and second bore portions on opposite sides of the valve member; and a spring means operatively engaging the valve member to bias it in the opposite direction from the net force exerted by the fluid pressure acting on the valve member, whereby the valve member shifts to its first position when the fluid pressure falls below a first predetermined pressure, to its second position when the pressure exceeds the first predetermined pressure, and to its startup position when the pressure falls below a predetermined value below the first predetermined pressure.
Claim 9
Dependent Claim
259 words
In a hydraulic system having a source of fluid pressure, a reservoir, and a plurality of hydraulic functions, including priority and nonpriority hydraulic functions, the improvement comprising: a valve body having a cylindrical valve bore with a first bore portion and a second portion having a smaller diameter than the first bore portion; first, second, third and fourth conduit means respectively connecting the valve bore to the fluid pressure source, at least one priority function, at least one nonpriority function and the reservoir; an axially slidable valve member having first and second diameter portions respectively, conforming to and disposed within the first and second bore portions and axially slidable between a first position wherein it establishes fluid communication between the first conduit means and the second conduit means only, a second position wherein it establishes fluid communication between the first, second, and third conduit means only, and a startup position wherein it connects the first conduit means to the fourth conduit means; a pressure-sensing passage means interconnecting the first and second bore portions on opposite sides of the valve member; and a spring means operatively engaging the valve member to bias it in the opposite direction from the net force exerted by the fluid pressure acting on the valve member, whereby the valve member shifts to its first position when the fluid pressure falls below a first predetermined pressure, to its second position when the pressure exceeds the first predetermined pressure, and to its startup position when the pressure falls below a predetermined value below the first predetermined pressure.
Claim 10
Dependent Claim
39 words
The invention defined in claim 7 wherein the pressure sensing passage means includes an orifice and the first conduit means is connected to the fourth conduit means through said orifice when the valve member is in its startup position.
Claim 11
Dependent Claim
40 words
The invention defined in claim 8 wherein the valve member is shiftable into a relief position wherein it connects the third conduit means to the fourth conduit means when the pressUre exceeds a predetermined value above said first predetermined value.
Claim 12
Dependent Claim
25 words
The invention defined in claim 8 wherein the passage means extends axially through the valve member and the orifice is disposed within the valve member.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |