US3679019A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle guidance systems
Assignee: Individual
•
Filing: 1970-06-29
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Granted: 1972-07-25
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Expires: 1990-06-29
Abstract
Abstract A vehicle guidance system in which a vehicle (e.g., a tractor) follows a conductor carrying a guidance signal. Steering control is effected in response to an error signal representative of divergence of the vehicle from the required track. A pulse generator gives a variable mark/space ratio output in accordance with the amplitude of the error signal and the pulse generator output is directed to operate a left- or right-hand on-off fluid valve in accordance with the sign of the error signal. The fluid valves are thus controlled by the variable mark/space signal to give proportional control although they are on-off valves.
Inventors
- 👤 Stephen William Hobday
- 👤 David Stephen Hobday
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:37
CPC Classifications
A; A01; A01B; A01B69/00; A01B69/007; A01B69/008; G; G05; G05D; G05D1/00; G05D1/02; G05D1/021; G05D1/0259; G05D1/0265
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
A vehicle guidance system in which a vehicle is steered to follow an electric conductor in response to signals emitted by the conductor, the vehicle having mounted thereon a signal detector comprising a pair of mutually perpendicular coils; a phase discriminator for deriving from the phase difference of signals in the two coils, an error signal representative in magnitude and sign of the positional error of the vehicle in relation to the conductor; a pUlse-train generator for generating a train of control pulses having a mark/space ration dependant upon the magnitude of the error signal; gate means for directing the pulse train to energize a first or a second steering solenoid in dependence on the sign of the error signal; and a fluidactuated steering ram arrangement provided with right and left on-off valves operated respectively by the first and second solenoids to steer the vehicle to the right and left.
Claim 2
Dependent Claim
150 words
A vehicle guidance system in which a vehicle is steered to follow an electric conductor in response to signals emitted by the conductor, the vehicle having mounted thereon a signal detector comprising a pair of mutually perpendicular coils; a phase discriminator for deriving from the phase difference of signals in the two coils, an error signal representative in magnitude and sign of the positional error of the vehicle in relation to the conductor; a pUlse-train generator for generating a train of control pulses having a mark/space ration dependant upon the magnitude of the error signal; gate means for directing the pulse train to energize a first or a second steering solenoid in dependence on the sign of the error signal; and a fluidactuated steering ram arrangement provided with right and left on-off valves operated respectively by the first and second solenoids to steer the vehicle to the right and left.
Claim 3
Dependent Claim
22 words
A system as claimed in claim 1, wherein one coil has a vertical axis and the other coil has a horizontal axis.
Claim 4
Dependent Claim
38 words
A system as claimed in claim 1, including a feedback circuit mechanically coupled to the vehicle steering mechanism to generate a feedback signal which is combined with the output from the discriminator means to give the error signal.
Claim 5
Dependent Claim
40 words
A system as claimed in claim 1, wherein the steering solenoids open their respective on-off valves when receiving the ''''marks'''' of the pulse train and the pulse-train generator has a range of ''''mark'''' time control from 10 to 100 percent.
Claim 6
Dependent Claim
18 words
A system as claimed in claim 1, wherein the frequency of the pulse train is approximately 10 Hz.
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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |