US3731746A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Weight transfer hitch
Assignee: Deutz Allis Corp
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Filing: 1971-11-18
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Granted: 1973-05-08
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Expires: 1991-11-18
Abstract
Abstract An electrically controlled hydraulic cylinder having a variable resistor and a bridge circuit for preselecting the desired length of a remote hydraulic cylinder in the hydraulic system of a tractor.
Inventors
- 👤 M Walberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:56
CPC Classifications
A; A01; A01B; A01B59/00; A01B59/04; A01B59/042; A01B59/043; A01B63/00; A01B63/02; A01B63/10; A01B63/111; A01B63/112; A01B63/14; A01B63/16; A01B63/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
179 words
In a tractor having a hitch and an implement connected thereto, a hydraulic system for controlling the position of said implement comprising, a hydraulic actuator connected to said hitch, an electrical system on said tractor including a bridge circuit having four resistance legs, a source of electrical energy connected across said bridge circuit, a manually controlled variable resistance forming one of said legs, a hydraulically controlled variable resistance forming another of said legs of said bridge circuit, a hydraulic actuator connected to the hydraulically controlled variable resistance of said other leg of said bridge circuit, a source of pressurized fluid, a solenoid valve hydraulically connected between said hydraulic actuator and said source of pressurized fluid, a voltage sensing circuit connected to said bridge for sensing an unbalanced voltage produced in said bridge circuit, a solenoid valve operating circuit connected to said solenoid valve and said voltage sensing circuit to thereby provide means for varying the resistance in said bridge circuit and produce a voltage signal for operating said solenoid valve to hydraulically adjust the length of said hydraulic actuator.
Claim 2
Dependent Claim
179 words
In a tractor having a hitch and an implement connected thereto, a hydraulic system for controlling the position of said implement comprising, a hydraulic actuator connected to said hitch, an electrical system on said tractor including a bridge circuit having four resistance legs, a source of electrical energy connected across said bridge circuit, a manually controlled variable resistance forming one of said legs, a hydraulically controlled variable resistance forming another of said legs of said bridge circuit, a hydraulic actuator connected to the hydraulically controlled variable resistance of said other leg of said bridge circuit, a source of pressurized fluid, a solenoid valve hydraulically connected between said hydraulic actuator and said source of pressurized fluid, a voltage sensing circuit connected to said bridge for sensing an unbalanced voltage produced in said bridge circuit, a solenoid valve operating circuit connected to said solenoid valve and said voltage sensing circuit to thereby provide means for varying the resistance in said bridge circuit and produce a voltage signal for operating said solenoid valve to hydraulically adjust the length of said hydraulic actuator.
Claim 3
Dependent Claim
39 words
A control system as set forth in claim 1 wherein said voltage sensing circuit includes transistors conducting current in response to the unbalanced voltage sensed, a relay circuit connected to said voltage sensing circuit to operate said solenoid valve.
Claim 4
Dependent Claim
66 words
A control system as set forth in claim 1 wherein said solenoid valve includes means providing three positions of said solenoid valve for transmitting hydraulic fluid to and from said hydraulic actuator for extending and retracting said actuator, means in said solenoid valve to lock hydraulic fluid in said hydraulic actuator to retain a predetermined length of said hydraulic actuator when said solenoid valve is closed.
Claim 5
Dependent Claim
51 words
A control system as set forth in claim 1 wherein said bridge circuit Includes a Wheatstone bridge, a battery connected across said Wheatstone bridge, said voltage sensing circuit including means connected between the two resistance legs on each side of said bridge circuit to sense a voltage unbalance in said circuit.
Claim 6
Dependent Claim
97 words
A control system as set forth in claim 1 wherein said bridge circuit includes a pair of resistors connected in series forming one side of the bridge, a pair of resistors connected in series forming the other side of said bridge, a battery connected across both of said pairs of resistors, a pressure sensitive transducer connected in series with one of said resistors forming one leg of said bridge circuit, said transducer thereby varying the voltage across one pair of said resistors to produce an unbalance in said bridge circuit in response to pressure on said transducer.
Claim 7
Dependent Claim
35 words
A control system as set forth in claim 1 including means on said implement connected to said hydraulic actuator for controlling operation of said implement in response to a change in said manually controlled resistance.
Claim 8
Dependent Claim
33 words
A control system as set forth in claim 1 wherein said hitch is a three point hitch, the upper link of which includes said hydraulic actuator for thereby providing an implement leveling means.
Claim 9
Dependent Claim
29 words
A control system as set forth in claim 1 including means defining an operator station on said tractor, means for supporting said manually controlled resistance at said operator station.
Claim 10
Dependent Claim
91 words
A control system as set forth in claim 1 wherein said bridge circuit includes, a rheostat defining a first and second resistance legs and having a center tap on said rheostat connected to said voltage sensing circuit and manual control means, a resistor defining the third and fourth resistance legs and having a center tap connected to said hydraulic actuator and said voltage sensing circuit, said manual control means thereby providing a means for varying the position of said center tap on said rheostat and the length of said hydraulic actuator.
Claim 11
Dependent Claim
88 words
A control system as set forth in claim 1 wherein said bridge circuit includes a variable resistor having a center tap with one end connected to said source of electrical energy, a transducer connected between the other end of said resistor and said source of electrical energy, a rheostat having two terminals connected across said battery and a center tap, said voltage sensing circuit including means connected to the center taps of said rheostat and said variable resistor to provide a voltage sensing circuit on said bridge circuit.
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) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |