US3872985A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic control valve circuit
Assignee: Case LLC
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Filing: 1972-02-14
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Granted: 1975-03-25
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Expires: 1992-02-14
Abstract
Abstract A hydraulic system in a material handling device in which a movable member is rotated about a pivot point, by a pair of hydraulic motors reversibly operable in response to the selective application of hydraulic pressure thereto. The hydraulic pressure for operating the hydraulic motors is connected thereto through a hydraulic switching valve responsive to the position of said movable member where one hydraulic motor would normally oppose further rotation of the movable member to modify the hydraulic connections to that hydraulic motor in response to said member reaching that position whereby further rotation of the movable member is effected without opposition from the hydraulic motor.
Inventors
- 👤 Arthur G Short
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:20
CPC Classifications
B; B66; B66C; B66C23/00; B66C23/62; B66C23/84; B66C23/86; E; E02; E02F; E02F3/00; E02F3/04; E02F3/28; E02F3/36; E02F3/38; E02F3/382; E02F3/384
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
197 words
In a backhoe mounted on a tractor, the combination of a support on the rear end of the said tractor; a boom pivotally mounted on sAid support at a first pivot for rotation between extreme lateral positions about a substantially vertical pivot axis; first and second hydraulic motor means each having first and second relatively movable elements, one of said elements of each motor means being pivotally connected to said support and the other of said elements being pivotally connected to said boom; a source of fluid under pressure; a reservoir; conduit means connecting said source and reservoir to opposite ends of said first element of each hydraulic motor means; and control valve means in said conduit means, said control valve means having a first position for supplying fluid under pressure to one end of each of said first elements and connecting the opposite ends to said reservoir to rotate said boom between said extreme positions and a second position for allowing free floating movement of the elements of one of said hydraulic motor means when its pivots are on a line intersecting said first pivot while continuing rotation of said boom with said other motor means.
Claim 2
Dependent Claim
197 words
In a backhoe mounted on a tractor, the combination of a support on the rear end of the said tractor; a boom pivotally mounted on sAid support at a first pivot for rotation between extreme lateral positions about a substantially vertical pivot axis; first and second hydraulic motor means each having first and second relatively movable elements, one of said elements of each motor means being pivotally connected to said support and the other of said elements being pivotally connected to said boom; a source of fluid under pressure; a reservoir; conduit means connecting said source and reservoir to opposite ends of said first element of each hydraulic motor means; and control valve means in said conduit means, said control valve means having a first position for supplying fluid under pressure to one end of each of said first elements and connecting the opposite ends to said reservoir to rotate said boom between said extreme positions and a second position for allowing free floating movement of the elements of one of said hydraulic motor means when its pivots are on a line intersecting said first pivot while continuing rotation of said boom with said other motor means.
Claim 3
Dependent Claim
27 words
A backhoe as defined in claim 1 in which said first elements are fluid cylinders and said second elements are piston rods slidable relative to said cylinders.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |