US3575241A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tractor hydraulic lift control system
Assignee: Ford Motor Co
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Filing: 1967-03-30
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Granted: 1971-04-20
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Expires: 1987-03-30
Abstract
Abstract A tractor is provided with a torque-sensing device in the drive line to the tractor driving wheels to control operation of an implement hydraulic lift system for raising and lowering an implement as required to maintain a constant torque on the drive line. The system also provides for implement positioning responsive to position of a hand-operated quadrant lever and for positioning responsive to both drive line torque and quadrant lever position.
Inventors
- 👤 Charles E Mckeon
- 👤 William F Lomas
- 👤 Willard G Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 18:00
CPC Classifications
A; A01; A01B; A01B67/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
156 words
In a tractor having an engine, a transmission, a rear axle, a pair of driving wheels mounted on the rear axle for propelling the tractor, a drive shaft connecting the transmission and rear axle, implement supporting means on the tractor adapted to receive a ground-working implement, hydraulic cylinder means for raising and lowering said implement supporting means, a source of hydraulic fluid under pressure, valve means for controlling flow of fluid to and from said hydraulic cylinder means for regulating implement height, and a torque-sensing coupling interposed in the drive line between the transmission and rear axle and operatively connected to said valve means for controlling said valve means to raise the implement upon said drive line torque exceeding a predetermined figure and lower the implement upon drive line torque dropping below a slightly lower predetermined figure so as to maintain a substantially uniform predetermined drive line torque during operation with the implement in ground-engaging position.
Claim 2
Dependent Claim
156 words
In a tractor having an engine, a transmission, a rear axle, a pair of driving wheels mounted on the rear axle for propelling the tractor, a drive shaft connecting the transmission and rear axle, implement supporting means on the tractor adapted to receive a ground-working implement, hydraulic cylinder means for raising and lowering said implement supporting means, a source of hydraulic fluid under pressure, valve means for controlling flow of fluid to and from said hydraulic cylinder means for regulating implement height, and a torque-sensing coupling interposed in the drive line between the transmission and rear axle and operatively connected to said valve means for controlling said valve means to raise the implement upon said drive line torque exceeding a predetermined figure and lower the implement upon drive line torque dropping below a slightly lower predetermined figure so as to maintain a substantially uniform predetermined drive line torque during operation with the implement in ground-engaging position.
Claim 3
Dependent Claim
24 words
In a tractor as claimed in claim 1, having manually settable means operatively connected to said valve means for predetermining the drive line torque.
Claim 4
Dependent Claim
40 words
In a tractor as claimed in claim 1, the torque-sensing coupling comprising a two-part coupling interposed in the drive line, one part of the coupling being circumferentially displaceable relative to the other part proportional to the amount of torque transmitted.
Claim 5
Dependent Claim
61 words
In a tractor as claimed in claim 1, means operatively connected with said ground engaging implement supporting hitch and said valve means for controlling the valve means in response to implement height and means operatively connected with said valve means and said torque-sensing means for varying the relative effect on the valve means of implement height And of drive line torque.
Claim 6
Dependent Claim
67 words
In a tractor as claimed in claim 1, in which the means for controlling the valve means includes a valve operating lever having one end portion manually positionable to predetermine the operating drive line torque, another portion connected with the valve means for operation of the valve means responsive to movement of the lever and a third portion moved responsive to variations in tractor drive line torque.
Claim 7
Dependent Claim
53 words
In a tractor as claimed in claim 5, a floating lever having one end displaced responsive to implement height, the other end displaced responsive to drive line torque, and an intermediate portion linked to the valve operating lever for displacing it responsive to change in implement height and change in drive line torque.
Claim 8
Dependent Claim
49 words
In a tractor as claimed in claim 6, the link connecting the valve operating lever and the floating lever having a connection with the floating lever movable from the implement height controlled end of the lever at least most of the way towards the other end of the lever.
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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |