US3860074A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro-hydraulic device for lifting tractor-drawn agricultural implements
Assignee: Renault SA
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Filing: 1973-02-15
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Granted: 1975-01-14
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Expires: 1993-02-15
Abstract
Abstract This electro-hydraulic device for lifting tractor-drawn agricultural implements comprises a first sensor delivering a voltage subordinate to the actual displacement of a tractive effort transmission member, a second sensor delivering another voltage subordinate to a tractive effort display, a governor comprising a first control path delivering a voltage subordinate to the discrepancy between the two voltages delivered by said sensors and supplying its voltage to an assembly for adjusting the fluid output to said implement lifting actuator via an auxiliary actuator adapted to monitor the output of a main feed pump for supplying fluid to said lifting actuator, said tractive effort transmission member comprising a shaft having at its ends anchor points for the traction arms and being associated with a pair of spring blades located adjacent supports and adapted to urge said shaft towards the tractor chassis.
Inventors
- 👤 Roger Maistrelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:38
CPC Classifications
A; A01; A01B; A01B63/00; A01B63/02; A01B63/10; A01B63/111; A01B63/112; F; F15; F15B; F15B21/00; F15B21/08; F15B21/087
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
208 words
An electro-hydraulic apparatus for lifting tractor-drawn agricultural implements, comprising: coupling means for coupling a tractor-drawn agricultural implement to a tractor; at least one resilient member fixed to said tractor and engaging said coupling means and biasing said coupling means toward said tractor; hydraulic actuating means mounted to said tractor and engaging said implement for moving said implement in a direction opposed to the biasing direction of said resilient member; a variable output hydraulic displacement pump coupled between said hydraulic actuating means and a main pressurized fluid source; pump actuating means coupled to said variable output pump for adjusting the output of said variable output pump; manually operated selector means coupled to said variable output pump for selecting a desired draft effort of said implement; first sensor means for detecting the actual draft effort of said implement; second sensor means for sensing the output of said selector means; means coupled to said first and second sensor means for comparing said selected and detected actual draft efforts and generating a signal proportional to the difference therebetween; and means coupling the output of said comparing means to said pump actuating means to control the output of said variable output pump as a function of the output signal from said comparing means.
Claim 2
Dependent Claim
208 words
An electro-hydraulic apparatus for lifting tractor-drawn agricultural implements, comprising: coupling means for coupling a tractor-drawn agricultural implement to a tractor; at least one resilient member fixed to said tractor and engaging said coupling means and biasing said coupling means toward said tractor; hydraulic actuating means mounted to said tractor and engaging said implement for moving said implement in a direction opposed to the biasing direction of said resilient member; a variable output hydraulic displacement pump coupled between said hydraulic actuating means and a main pressurized fluid source; pump actuating means coupled to said variable output pump for adjusting the output of said variable output pump; manually operated selector means coupled to said variable output pump for selecting a desired draft effort of said implement; first sensor means for detecting the actual draft effort of said implement; second sensor means for sensing the output of said selector means; means coupled to said first and second sensor means for comparing said selected and detected actual draft efforts and generating a signal proportional to the difference therebetween; and means coupling the output of said comparing means to said pump actuating means to control the output of said variable output pump as a function of the output signal from said comparing means.
Claim 3
Dependent Claim
114 words
The apparatus according to claim 1, further comprising: second selector means coupled to said variable output pump for selecting a desired working depth of said implement; third sensor means for detecting the actual working depth of said implement; fourth sensor means for sensing the output of said second selector means; and second means coupled to said third and fourth sensor means for comparing the selected and detected actual working depths and generating a signal proportional to the difference therebetween, the output of said second comparing means being coupled to said pump actuating means to control the output of said variable output pump as a function of the output signal of said second comparing means.
Claim 4
Dependent Claim
27 words
The apparatus according to claim 2, further comprising switch means for selectively coupling the outputs of said first and second comparing means to said pump actuating means.
Claim 5
Dependent Claim
31 words
The apparatus according to claim 3, further comprising means coupled to said second comparing means for prohibiting transmission of the outputs of said second comparing means to said pump actuating means.
Claim 6
Dependent Claim
31 words
The apparatus according to claim 4, wherein said transmission prohibiting means comprises a manually engageable, automatically disengaging safety interlock switch interposed between said selective switching means and said pump actuating means.
Claim 7
Dependent Claim
107 words
The apparatus according to claim 2, further comprising an auxiliary control member coupled to said pump actuating means and having a first position for supplying a first constant signal to said pump actuating means to control movement of said implement in a first direction, a second position for supplying a second constant signal different from said first constant signal to said pump actuating means to control movement of said implement in a second direction, and a third position for connecting the outputs of said comparing means to said pump actuating means to control movement of said implement as a function of the outputs of said comparing means.
Claim 8
Dependent Claim
63 words
The apparatus according to claim 1, wherein said variable output pump has a variable volumetric capacity and a bidirectional output; and said pump actuating means comprises means to adjust the volumetric capacity and output direction of said pump and means to reduce the volumetric capacity of said pump substantially to zero when no signal appears at the input of said pump actuating means.
Claim 9
Dependent Claim
215 words
The appparatus according to claim 7, wherein said pump actuating means further comprises: a secondary source of pressurized fLuid; a piston cylinder having first and second chambers separated by a piston; first and second conduits coupling said first and second chambers, respectively, to said secondary source; first and second solenoid operated valves interposed in said first and second conduits, respectively, to control the flow of fluid between said secondary source and said first and second chambers; a piston rod coupled to said piston, said rod being movable in opposite directions into first and second end positions, the stroke of the movement of said rod being a function of the fluid pressure respectively in said first and second chamber; a further resilient member coupled to said rod and urging said rod normally into a rest position intermediate said first and second end positions; a stress amplifier having a movable output member coupled to said piston rod and to said secondary source, the movement of said output member being a function of the position of said piston rod; and means coupling said output member of said stress amplifier to said variable output pump such that the volumetric capacity of said pump is controlled as a function of the movement of said output member of said stress amplifier.
Claim 10
Dependent Claim
43 words
The apparatus according to claim 7, wherein said rest position corresponds to a substantially zero volumetric capacity of said pump and said first and second end positions correspond to maximum volumetric capacities in each of the two output directions of said pump, respectively.
Claim 11
Dependent Claim
60 words
The apparatus according to claim 9, further comprising: a non-return valve interposed between said hydraulic actuating means and said variable output pump to prevent a return of fluid from said hydraulic actuating means to said variable output pump; and means monitoring the flow of fluid through said non-return valve as a function of the fluid pressure of said secondary source.
Claim 12
Dependent Claim
86 words
The apparatus according to claim 10, wherein said monitoring means comprises a monitoring valve interposed between said secondary source and said non-return valve, and means coupling said monitoring valve to said stress amplifier to close said monitoring valve to discontinue monitoring of said non-return valve when said volumetric capacity of said pump approaches zero; said apparatus further comprising a second non-return valve coupled between said variable output pump and a fluid reservoir to permit fluid to flow in one direction from said reservoir to said pump.
Claim 13
Dependent Claim
42 words
The apparatus according to claim 8, further comprising means coupling the output of said comparing means to said first and second solenoid operated valves to control the operation of said valves as a function of the output signal from said comparing means.
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) | 1978-01-13 | 1978-07-15 | 1979-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-13 | 1982-07-15 | 1983-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-13 | 1986-07-15 | 1987-01-14 | $7700.00 | Window Closed / Lapsed |