US3604312A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Draft control valve
Assignee: Deutz Allis Corp
•
Filing: 1969-10-23
•
Granted: 1971-09-14
•
Expires: 1989-10-23
Abstract
Abstract A draft control valve having metering grooves on the control spool to control the flow rate to the fluid actuator and a flow control valve transmitting return fluid flow from the fluid actuator through the control valve to the reservoir at a rate of flow independent of actuator operating pressure.
Inventors
- 👤 John R Plate
- 👤 James R Mc Burnett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:39
CPC Classifications
A; A01; A01B; A01B63/00; A01B63/02; A01B63/10; A01B63/111; A01B63/112; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2544; Y10T137/2559; Y10T137/2574; Y10T137/2605; Y10T137/2607
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
232 words
A draft control valve comprising, a housing defining a spool opening, a spool mounted for reciprocal movement in said opening, means defining an inlet passage adapted for connection to a pump, a sump passage adapted for connection to a sump, and an actuator passage adapted for connection to a hydraulic fluid actuator, a flow control valve operating in said actuator passage of said housing and defining a constant-pressure chamber, means defining feedback means having a piston-sensing pressure in said actuator passage and feeding back a pressure signal to said spool in opposition to a valve actuating force on said spool, said spool defining a metering orifice for selectively and alternatively providing communication between said inlet passage and said actuator passage in response to movement of said spool in a first direction, said spool defining a variable orifice with said housing for selectively connecting said constant-pressure chamber and said flow control valve with the sump passage in response to movement of said spool in a second direction, said spool thereby providing through selective positioning metered flow from the inlet passage to the actuator passage to operate the hydraulic actuator and permitting the flow of pressurized fluid from said hydraulic actuator through said flow control valve and said variable orifice defined by said spool in said housing to provide a predetermined rate of flow of pressurized fluid from said hydraulic actuator to said sump.
Claim 2
Dependent Claim
232 words
A draft control valve comprising, a housing defining a spool opening, a spool mounted for reciprocal movement in said opening, means defining an inlet passage adapted for connection to a pump, a sump passage adapted for connection to a sump, and an actuator passage adapted for connection to a hydraulic fluid actuator, a flow control valve operating in said actuator passage of said housing and defining a constant-pressure chamber, means defining feedback means having a piston-sensing pressure in said actuator passage and feeding back a pressure signal to said spool in opposition to a valve actuating force on said spool, said spool defining a metering orifice for selectively and alternatively providing communication between said inlet passage and said actuator passage in response to movement of said spool in a first direction, said spool defining a variable orifice with said housing for selectively connecting said constant-pressure chamber and said flow control valve with the sump passage in response to movement of said spool in a second direction, said spool thereby providing through selective positioning metered flow from the inlet passage to the actuator passage to operate the hydraulic actuator and permitting the flow of pressurized fluid from said hydraulic actuator through said flow control valve and said variable orifice defined by said spool in said housing to provide a predetermined rate of flow of pressurized fluid from said hydraulic actuator to said sump.
Claim 3
Dependent Claim
47 words
A draft control valve as set forth in claim 1 wherein said feedback means includes a lever and a mechanism for sensing the pressurized fluid in said actuator passage for feeding back a proportional force to said spool in opposition to the actuating force on said spool.
Claim 4
Dependent Claim
96 words
A draft control valve as set forth in claim 1 wherein said flow control valve includes a sleeve defining an orifice, means biasing said sleeve to open said orifice to the maximum opening whereby pressurized fluid in said constant-pressure chamber biases said sleeve in opposition to said biasing means to close said port and thereby control the flow of pressurized fluid from said actuator passage to said constant-pressure chamber in response to opening of said variable orifice defined by said spool and housing to control the flow through said flow control valve to a predetermined rate.
Claim 5
Dependent Claim
75 words
A draft valve as set forth in claim 1 wherein said flow control valve includes a sleeve having a port, resilient means biasing said sleeve to a position of maximum opening of said port, said resilient means biasing said sleeve includes a spring positioned for engaging an adjustable screw to provide a variable force transmitted from said spring to vary the rate of flow of said flow control valve when said valve is in operation.
Claim 6
Dependent Claim
52 words
A draft control valve as set forth in claim 1 wherein said housing defines a pilot passage having a check valve permitting the flow of pressurized fluid flowing through said metering orifice and check valve to transmit a pilot signal adapted for controlling the volume of displacement of a variable displacement pump.
Claim 7
Dependent Claim
60 words
A draft control valve as set forth in claim 1 having an actuating means including a manual means directly engaging said spool to selectively position said spool for controlling the flow of pressurized fluid through said draft control valve, an automatic means connected through a resilient means for transmitting a draft signal to said spool to selectively position said spool.
Claim 8
Dependent Claim
67 words
A draft control valve as set forth in claim 1 wherein said spool defines a tapered portion forming annular recess on the external periphery of said spool, a shoulder defined by said valve housing to define a variable-area orifice variable in response to positioning of said spool relative to said housing to thereby control the flow rate of discharge from said hydraulic fluid actuator to said sump.
Claim 9
Dependent Claim
80 words
A draft control valve as set forth in claim 1 wherein said housing defines a chamber encircling said spool selectively in communication with said metering orifice and in communication with said actuator passage including a check valve to permit the flow of pressurized fluid from said metering orifice to said hydraulic fluid actuator and block return flow to said chamber and thereby providing a holding means for said hydraulic actuator in event of loss of pressure in said inlet passage.
Claim 10
Dependent Claim
112 words
A draft control valve as set forth in claim 1 wherein said flow control valve includes a variable orifice defined by a sleeve, including a port communicating with said constant-pressure chamber and said actuator passage, means biasing said sleeve to provide maximum opening of said sleeve port, said sleeve thereby automatically positioning itself in response to the opening of said variable orifice defined by said spool in said housing to control the area of opening of said port on said sleeve to maintain a substantially constant pressure in said constant pressure chamber and control the rate of flow from said fluid actuator to said sump regardless of pressure in said actuator passage.
Claim 11
Dependent Claim
65 words
A draft control valve as set forth in claim 1 wherein said spool defines an annular recess in communication with said metering orifice, said housing defines an annular recess around said annular recess in said spool thereby defining a pressure chamber for supplying pressurized fluid to said metering orifice for flow of pressurized fluid to said hydraulic actuator when said draft control valve is operated.
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) | 1974-09-13 | 1975-03-15 | 1975-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-13 | 1979-03-15 | 1979-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-13 | 1983-03-15 | 1983-09-14 | $7700.00 | Window Closed / Lapsed |