US3762480A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic control apparatus for maintaining an agricultural implement parallel to the ground surface
Assignee: Robert Bosch GmbH
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Filing: 1971-02-22
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Granted: 1973-10-02
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Expires: 1991-02-22
Abstract
Abstract An agricultural implement, drawn by a tractor, is supported at the front and rear ends by front and rear cylinder and piston means, respectively. When the front end of the implement is raised, or lowered, by the front cylinder and piston means, fluid is automatically supplied to, or discharged from, respectively, the rear control cylinder and piston means for maintaining the implement in a position parallel to the ground surface.
Inventors
- 👤 F Hofer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:45
CPC Classifications
A; A01; A01B; A01B63/00; A01B63/14; A01B63/16; A01B63/22
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
300 words
In combination with a tractor and an agricultural implement drawn by the tractor, a hydraulic control apparatus for maintaining the implement parallel to the ground surface, comprising movable rear supporting means mounted on the trailing end of said implement for supporting the same on the ground for up and down movement; hydraulic rear support cylinder means and piston means mounted on said implement, one means of which includes a movable member for operating said rear supporting means to raise and lower said trailing end; movable front supporting means mounted on said tractor for supporting the leading end of said implement on said tractor for up and down movement; control cylinder means and control piston means on said tractor forming a rear control chamber and a front control chamber, said control piston means being operatively connected with said front supporting means; and a hydraulic control device on said tractor including a source of pressure fluid, first control conduit means connecting said source with said front control chamber, second control conduit means connecting said rear control chamber with said rear support cylinder means, and manually operated front coNtrol valve means in said first control conduit means operable to supply pressure fluid to, and discharge fluid from said front control chamber so that said control piston means is operated to actuate said front supporting means to raise and lower, respectively, said leading end of said implement, said front supporting means acting on said control piston means to vary the volume of said rear control chamber for supplying fluid to, and receiving fluid from said rear support cylinder means through said second control conduit so that said movable member operates said rear supporting means whereby said leading and trailing ends are simultaneously raised and lowered, and said implement remains parallel to the ground surface.
Claim 2
Dependent Claim
300 words
In combination with a tractor and an agricultural implement drawn by the tractor, a hydraulic control apparatus for maintaining the implement parallel to the ground surface, comprising movable rear supporting means mounted on the trailing end of said implement for supporting the same on the ground for up and down movement; hydraulic rear support cylinder means and piston means mounted on said implement, one means of which includes a movable member for operating said rear supporting means to raise and lower said trailing end; movable front supporting means mounted on said tractor for supporting the leading end of said implement on said tractor for up and down movement; control cylinder means and control piston means on said tractor forming a rear control chamber and a front control chamber, said control piston means being operatively connected with said front supporting means; and a hydraulic control device on said tractor including a source of pressure fluid, first control conduit means connecting said source with said front control chamber, second control conduit means connecting said rear control chamber with said rear support cylinder means, and manually operated front coNtrol valve means in said first control conduit means operable to supply pressure fluid to, and discharge fluid from said front control chamber so that said control piston means is operated to actuate said front supporting means to raise and lower, respectively, said leading end of said implement, said front supporting means acting on said control piston means to vary the volume of said rear control chamber for supplying fluid to, and receiving fluid from said rear support cylinder means through said second control conduit so that said movable member operates said rear supporting means whereby said leading and trailing ends are simultaneously raised and lowered, and said implement remains parallel to the ground surface.
Claim 3
Dependent Claim
114 words
Hydraulic control apparatus as claimed in claim 1 wherein said control cylinder means includes a front control cylinder and a rear control cylinder; wherein said control piston means includes a front control piston located in said front control cylinder and forming said front control chamber in the same, a rear control piston located in said rear control cylinder and forming said rear control chamber in the same; and linkage means mounted on said tractor connecting said front and rear control pistons with said front supporting means and with each other so that when the volume of said front control chamber increases or decreases, the volume of said rear control chamber decreases or increases, respectively.
Claim 4
Dependent Claim
58 words
Hydraulic control apparatus as claimed in claim 2 wherein said front and rear control pistons have piston rods; wherein said linkage means include a lever mounted on said tractor for angular movement about an axis and being pivotally connected with said piston rods at two spaced points, and link means connecting said lever with said front supporting means.
Claim 5
Dependent Claim
83 words
Hydraulic control apparatus as claimed in claim 1 wherein said control piston means is located in said control cylinder means forming on opposite sides thereof siid front and rear control chambers so that when the volume of said front control chamber increases or decreases, the volume of said rear control chamber decreases or increases, respectively; wherein said control piston means has a piston rod projecting out of said control cylinder means; and linkage means connecting said piston rod with said front supporting means.
Claim 6
Dependent Claim
52 words
Hydraulic control apparatus as claimed in claim 4 wherein said linkage means include a lever having one end mounted on said tractor for angular movement about an axis, link means connecting the other end of said lever with said front supporting means; and pivot means connecting said piston rod with said lever.
Claim 7
Dependent Claim
48 words
Hydraulic control apparatus as claimed in claim 1 comprising a hydraulic rear end adjusting device including manually operated rear end control valve means in said conduit means operable to supply pressure fluid to, and to discharge fluid from said rear support cylinder means for actuating said movable member.
Claim 8
Dependent Claim
65 words
Hydraulic control apparatus as claimed in claim 6 wherein said rear end control valve means includes a valve slide means and a handle for operating said valve slide means between a neutral position for closing said rear support cylinder means, a raising position for supplying pressure fluid to said rear support means, and a lowering position for discharging fluid from said rear support cylinder means.
Claim 9
Dependent Claim
65 words
Hydraulic control apparatus as claimed in claim 7 comprising a pump having a pressure conduit means and a return means; wherein said pressure conduit means communicates with said rear end adjusting device and said rear end control valve means, after communicating with said hydraulic control device and said front control valve means; and wherein rear end adjusting device and said control device have adjacent housings.
Claim 10
Dependent Claim
169 words
Hydraulic control apparatus as claimed in claim 1 wherein said control cylinder means includes a front control cylinder and a rear control cylinder; wherein said control piston means includes a front control piSton located in said front control cylinder and forming said front control chamber in the same, a rear control piston located in said rear control cylinder and forming said rear control chamber in the same; and linkage means mounted on said tractor connecting said front and rear control pistons with said front supporting means and with each other so that when the volume of said front control chamber increases or decreases, the volume of said rear control chamber decreases or increases, respectively; adjustable throttle means in said second control conduit means; resilient means between said rear control piston and said linkage wherein said rear control piston forms another chamber on the side thereof remote from said rear control chamber; and a discharge conduit connected with said other chamber for discharging fluid from the same at low pressure.
Claim 11
Dependent Claim
48 words
Hydraulic control apparatus as claimed in claim 9 wherein said rear control piston has a hollow piston rod in said other chamber projecting out of the same and being connected with said linkage means; and wherein said resilient means include a spring located in said hollow piston rod.
Claim 12
Dependent Claim
16 words
Hydraulic control apparatus as claimed in claim 9 wherein said resilient means include a hydraulic accumulator.
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) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |