US3695474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic control linkage for implement
Assignee: Case LLC
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Filing: 1970-08-05
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Granted: 1972-10-03
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Expires: 1990-08-05
Abstract
Abstract A hydraulic circuit or linkage system for controlling the attitude of an implement relative to a fixed support while the implement is being raised and lowered relative to the support. The implement is pivoted on one end of a boom by a fluid ram having pressurized fluid supplied thereto through a control valve. The hydraulic control linkage includes a master piston and cylinder assembly interposed between the implement and the support with a slave piston cooperating with the valve spool of the control valve and slidable in a slave cylinder. The opposite ends of the two cylinders are interconnected so that the slave piston is moved in response to movement of the master piston to automatically maintain the predetermined attitude of the implement relative to a fixed reference plane. The hydraulic control linkage further includes mechanism for automatically stopping the bucket at a desired angular relation while it is moving between a first and a second maximum pivoted position and automatically preventing the movement of the bucket beyond the second maximum pivoted position. This is accomplished through a valve having a plurality of flow paths between the conduits interconnecting opposite ends of the two cylinders.
Inventors
- 👤 Richard P Blakely
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:21
CPC Classifications
E; E02; E02F; E02F3/00; E02F3/04; E02F3/28; E02F3/36; E02F3/42; E02F3/43; E02F3/431; E02F3/434; E02F3/432; E02F3/433
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
189 words
A material handling device comprising a vehicle having one end of a boom pivotally supported thereon with a material handling implement movable on the opposite end of said boom; hydraulic means for moving said implement on said boom and including a fluid motor having relatively movable elements, respectively, connected to the boom and the implement; said hydraulic means further including a fluid source under pressure, a reservoir, a valve and conduit means interconnecting said valvE, motor, source and reservoir; said valve having a spool slidable in a chamber and movable in opposite directions from a neutral position to move said implement in opposite directions on said boom, the improvement of a hydraulic control linkage means interposed between said spool and said implement for causing actuation of the spool and consequently (1) maintaining said implement at a predetermined angle relative to a fixed reference plane during raising of said boom; (2) preventing movement of said implement beyond a first maximum angle relative to said reference plane; and (3) returning said implement to a desired angle relative said reference plane after said implement has been moved to a second maximum angle.
Claim 2
Dependent Claim
189 words
A material handling device comprising a vehicle having one end of a boom pivotally supported thereon with a material handling implement movable on the opposite end of said boom; hydraulic means for moving said implement on said boom and including a fluid motor having relatively movable elements, respectively, connected to the boom and the implement; said hydraulic means further including a fluid source under pressure, a reservoir, a valve and conduit means interconnecting said valvE, motor, source and reservoir; said valve having a spool slidable in a chamber and movable in opposite directions from a neutral position to move said implement in opposite directions on said boom, the improvement of a hydraulic control linkage means interposed between said spool and said implement for causing actuation of the spool and consequently (1) maintaining said implement at a predetermined angle relative to a fixed reference plane during raising of said boom; (2) preventing movement of said implement beyond a first maximum angle relative to said reference plane; and (3) returning said implement to a desired angle relative said reference plane after said implement has been moved to a second maximum angle.
Claim 3
Dependent Claim
90 words
A material handling device as defined in claim 1, in which said hydraulic control linkage means further includes means defining a chamber adjacent said spool; a slave piston slidable in said chamber and connected to said spool; a piston rod and cylinder assembly having elements respectively connected to said vehicle and said implement and conduit means connecting opposite ends of said cylinder to opposite ends of said chamber with hydraulic fluid in said conduit means, said cylinder and said chamber whereby relative movement between said elements will actuate said valve.
Claim 4
Dependent Claim
60 words
A material handling device as defined in claim 2, in which said hydraulic means includes manual means for moving said valve spool, the further improvement of means in said hydraulic control linkage means for allowing said valve spool to remain in a manually actuated position by accommodating movement of said elements while said slave piston is in a fixed position.
Claim 5
Dependent Claim
38 words
A material handling device as defined in claim 3, including the further improvement of mechanism in said hydraulic control linkage means for locking said elements relative to each other when said implement is at said first maximum angle.
Claim 6
Dependent Claim
74 words
A material handling device as defined in claim 4, including biasing means normally maintaining said valve spool in a neutral position and biased detent means maintaining said valve spool in an actuated position for moving said implement from said second maximum angle toward said first maximum angle; the further improvement of means in said hydraulic control linkage means for returning said valve spool to said neutral position when said implement reaches said desired angle.
Claim 7
Dependent Claim
91 words
A material handling device as defined in claim 2, in which said conduit means includes first and second conduits having opposite ends respectively connected to opposite ends of said cylinder and said chamber, the further improvement of a flow control valve defining first and second unidirectional flow paths in opposite directions and biased valve means in said flow paths normally blocking flow through said flow paths, said valve means accommodating flow in opposite directions between said conduits upon manual actuation of said valve spool in opposite directions from said neutral position.
Claim 8
Dependent Claim
31 words
A material handling device as defined in claim 6, the further improvement of mechanism for blocking flow through one of said flow paths when said implement reaches said first maximum angle.
Claim 9
Dependent Claim
87 words
A material handling device as defined in claim 6, in which said second flow path includes first and second parallel branch paths between said conduits, each having biased valve means therein; means for blocking flow through said first branch path when said implement reaches said desired angle to return said valve spool to said neutral position, said second branch path accommodating flow between said conduits upon subsequent manual actuation of said valve spool; and means blocking both branch paths when said implement reaches said first maximum angle.
Claim 10
Dependent Claim
131 words
In a vehicle having a boom pivoted on a support between raised and lowered positions, an implement pivoted on said boom, power means for pivoting said implement on said support between first and second positions, a control valve having a self-centering spool moVable in opposite directions from a neutral position to direct fluid to and from said power means and pivot said implement, the improvement of separate hydraulic linkage means between said support, said implement and said valve spool for automatically moving said spool to any one of said positions and maintain said implement at a predetermined angle relative to a fixed reference plane during raising and lowering of said boom, said hydraulic linkage means including means for preventing actuation of said valve spool when said implement reaches said second position.
Claim 11
Dependent Claim
131 words
In a vehicle having a boom pivoted on a support between raised and lowered positions, an implement pivoted on said boom, power means for pivoting said implement on said support between first and second positions, a control valve having a self-centering spool moVable in opposite directions from a neutral position to direct fluid to and from said power means and pivot said implement, the improvement of separate hydraulic linkage means between said support, said implement and said valve spool for automatically moving said spool to any one of said positions and maintain said implement at a predetermined angle relative to a fixed reference plane during raising and lowering of said boom, said hydraulic linkage means including means for preventing actuation of said valve spool when said implement reaches said second position.
Claim 12
Dependent Claim
53 words
A vehicle as defined in claim 9, in which said hydraulic linkage means includes a slave cylinder and slave piston cooperating with said spool, and means interposed between said support and said implement for moving said slave piston in said slave cylinder in response to movement of said implement relative to said support.
Claim 13
Dependent Claim
36 words
A vehicle as defined in claim 10, in which said last means includes a master cylinder connected to said support and a master piston connected to connected implement; and conduits interconnecting opposite ends of said cylinders.
Claim 14
Dependent Claim
59 words
A vehicle as defined in claim 9, in which said hydraulic linkage means includes an assembly having cylinder and piston elements respectively connected to said support and said implement and means operatively connecting opposite ends of said cylinder element to said spool to move said spool in response to movement of said piston element relative to said cylinder element.
Claim 15
Dependent Claim
71 words
A vehicle as defined in claim 9, in which said hydraulic linkage means includes a master cylinder having a master piston slidable therein and interposed between said support and said implement; a slave cylinder having a piston slidable therein and connected to said spool; and first and second conduits connecting opposite ends of said cylinders, said conduits defining first and second closed fluid paths between opposite ends of the respective pistons.
Claim 16
Dependent Claim
41 words
A vehicle as defined in claim 13, including the further improvement of valve means interposed between said fluid paths and operative upon manual actuation of said spool in opposite directions from a neutral position to allow independent movement of said bottom.
Claim 17
Dependent Claim
43 words
A vehicle as defined in claim 14, in which said valve means defines first and second normally closed flow paths between said fluid paths and biased means in said flow paths responsive to manual movement of said spool to open said flow paths.
Claim 18
Dependent Claim
59 words
A vehicle as defined in claim 15, in which one of said flow paths has first and second parallel branch paths, each having valves normally blocking flow therein, said valves respectively being responsive to first and second pressures of fluid in one of said fluid paths, to connect said one of said fluid paths with the other fluid path.
Claim 19
Dependent Claim
148 words
In combination with a vehicle having one end of a boom pivoted thereon and an implement pivoted on the opposite end of the boom between first and second positions by a fluid motor supplied with fluid through a valve having a spool biased to a neutral position, a hydraulic control linkage interposed between the vehicle, implement and valve spool and comprising a master piston and cylinder assembly having elements respectively connected to the vehicle and implement; a slave piston and cylinder assembly cooperating with said valve spool; and first and second conduits interconnecting respective ends of said cylinder elements and having hydraulic fluid therein whereby movement of said implement toward and away from said vehicle will actuate said valve in opposite directions from said neutral position to maintain said implement in a level position relative to said vehicle while the boom is raised and lowered on the vehicle.
Claim 20
Dependent Claim
148 words
In combination with a vehicle having one end of a boom pivoted thereon and an implement pivoted on the opposite end of the boom between first and second positions by a fluid motor supplied with fluid through a valve having a spool biased to a neutral position, a hydraulic control linkage interposed between the vehicle, implement and valve spool and comprising a master piston and cylinder assembly having elements respectively connected to the vehicle and implement; a slave piston and cylinder assembly cooperating with said valve spool; and first and second conduits interconnecting respective ends of said cylinder elements and having hydraulic fluid therein whereby movement of said implement toward and away from said vehicle will actuate said valve in opposite directions from said neutral position to maintain said implement in a level position relative to said vehicle while the boom is raised and lowered on the vehicle.
Claim 21
Dependent Claim
62 words
The combination as defined in claim 17, the further improvement of valve means between said conduits defining first and second flow paths between said conduits with relief valves in said paths and responsive to a first pressure of said hydraulic fluid in said respective conduits to provide flow in opposite directions between said conduits to accommodate manual actuation of said valve spool.
Claim 22
Dependent Claim
36 words
The combination as defined in claim 18, including the further improvement of means for blocking flow in one of said paths when said implement reaches said first position to prevent manual actuation of said valve spool.
Claim 23
Dependent Claim
112 words
The combination as defined in claim 18, including the further improvement of one of said flow paths having first and second branch paths with said relief valve of said flow path located in said first branch path, a further relief valve in said second branch path and being responsive to a second pressure greater than said first pressure; and means for blocking flow in said first branch path to position said implement in an intermediate position between said second and level positions, said further relief valve accommodating flow between said conduits upon subsequent manual actuation of said spool to accommodate movement of said implement from said intermediate position to said first position.
Claim 24
Dependent Claim
40 words
The combination as defined in claim 20, including the further improvement of means blocking flow in both branch paths when the implement reaches said first position to prevent manual actuation of said valve spool for movement beyond said second position.
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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |