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US3753467A
Expired / Lapsed
US
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Tractor-implement hydraulic lift system
Assignee: Ford Motor Co
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Filing: 1971-12-27
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Granted: 1973-08-21
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Expires: 1991-12-27
Abstract
Abstract A tractor having an implement hitch which is lifted and lowered by a hydraulic lift system responsive to driveline torque is coupled to the hydraulic lift system of an implement attached to the rear of the tractor to control the implement hydraulic lift system responsive to driveline torque of the tractor.
Inventors
- 👤 R Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:51
CPC Classifications
A; A01; A01B; A01B63/00; A01B63/14; A01B63/16; A01B63/22
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
146 words
The combination of a tractor having a liftable implement hitch, a single acting hydraulic lift cylinder connected with the hitch, a source of hydraulic fluid under pressure, a control valve for controlling admission of fluid to and escape of fluid from said cylinder to regulate the height of the hitch and means for actuating said control valve responsive to driveline torque to maintain a more or less uniform predetermined torque; and a soil-working implement pulled behind the tractor, said implement having an adjustable gauge wheel to limit depth of penetration of the implement and having a double acting hydraulic cylinder for raising and lowering the gauge wheel, one end of the implement cylinder being connected to the tractor lift cylinder and the other end of the implement cylinder being connected to the control valve whereby the implement cylinder and tractor lift cylinder are operated in unison.
Claim 2
Dependent Claim
146 words
The combination of a tractor having a liftable implement hitch, a single acting hydraulic lift cylinder connected with the hitch, a source of hydraulic fluid under pressure, a control valve for controlling admission of fluid to and escape of fluid from said cylinder to regulate the height of the hitch and means for actuating said control valve responsive to driveline torque to maintain a more or less uniform predetermined torque; and a soil-working implement pulled behind the tractor, said implement having an adjustable gauge wheel to limit depth of penetration of the implement and having a double acting hydraulic cylinder for raising and lowering the gauge wheel, one end of the implement cylinder being connected to the tractor lift cylinder and the other end of the implement cylinder being connected to the control valve whereby the implement cylinder and tractor lift cylinder are operated in unison.
Claim 3
Dependent Claim
37 words
The combination of a tractor and implement as claimed in claim 1, in which a spring connected with the tractor hitch biases the hitch downwardly and the implement is pulled directly from the body of the tractor.
Claim 4
Dependent Claim
32 words
The combination of a tractor and implement as claimed in claim 2, in which a coil type tension spring is connected between a lift arm of the hitch and the tractor body.
Claim 5
Dependent Claim
33 words
The combination of a tractor and implement as claimed in claim 1, in which the displacement of the tractor lift cylinder is slightly in excess of the displacement of the implement lift cylinder.
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) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |