US3669207A — Vehicle guidance systems

Claim 1

Independent Claim 294 words

In a system operable for guiding a vehicle in a desired path in generally parallel relation to and spaced a predetermined substantial offset distance from a predetermined plane, first means arranged for mounting on the vehicle, second means including an elongated guide in said predetermined plane and in generally parallel relation to said desired path, said first and second means being arranged for signal transmission therebetween with one of said first and second means including signal emitter means and the other including reception means operative to develop first and second signals having strength which vary with the distance between said first and second means according to different functions, said different functions being such that an algebraic summation in which said first and second signals are applied in opposed relation is of one effective polarity when the distance between said first means and said predetermined plane is greater than said predetermined substantial offset distance, of an opposite effective polarity when the distance between said first means and said predetermined plane is less than said predetermined substantial offset distance and zero when the distance between said first means and said predetermined plane is equal to said predetermined substantial offset distance, and comparison means for comparing the strength of said first and second signals to develop a steering signal which indicates uniquely the spatial relationship of the vehicle to said predetermined plane, said comparison means being responsive to said algebraic summation and being effective to develop a steering signal of one effective polarity when the distance between said first means and said predetermined plane is greater than said predetermined substantial offset distance and of an opposite effective polarity when the distance between said first means and said predetermined plane is less than said predetermined substantial offset distance.

Claim 2

Dependent Claim 294 words

In a system operable for guiding a vehicle in a desired path in generally parallel relation to and spaced a predetermined substantial offset distance from a predetermined plane, first means arranged for mounting on the vehicle, second means including an elongated guide in said predetermined plane and in generally parallel relation to said desired path, said first and second means being arranged for signal transmission therebetween with one of said first and second means including signal emitter means and the other including reception means operative to develop first and second signals having strength which vary with the distance between said first and second means according to different functions, said different functions being such that an algebraic summation in which said first and second signals are applied in opposed relation is of one effective polarity when the distance between said first means and said predetermined plane is greater than said predetermined substantial offset distance, of an opposite effective polarity when the distance between said first means and said predetermined plane is less than said predetermined substantial offset distance and zero when the distance between said first means and said predetermined plane is equal to said predetermined substantial offset distance, and comparison means for comparing the strength of said first and second signals to develop a steering signal which indicates uniquely the spatial relationship of the vehicle to said predetermined plane, said comparison means being responsive to said algebraic summation and being effective to develop a steering signal of one effective polarity when the distance between said first means and said predetermined plane is greater than said predetermined substantial offset distance and of an opposite effective polarity when the distance between said first means and said predetermined plane is less than said predetermined substantial offset distance.

Claim 3

Dependent Claim 74 words

In a system as defined in claim 1, said reception means including first and second sensing means for developing said first and second signals and positioned at different distances from said emitter means, the distance from said emitter means to said first sensing means being less than the distance from said emitter means to said second means, and said first sensing means having an effective sensitivity less than that of said second sensing means.

Claim 4

Dependent Claim 110 words

In a system as defined in claim 2, said reception means being associated with said first means and being mounted on said vehicle and said emitter means being associated with said second means and including an elongated cable forming said elongated guide and energized to develop an alternating electromagnetic field of a certain frequency, the intensity of said field being a function of the distance from said predetermined plane and the direction of said field at said reception means being generally parallel to said predetermined plane, said first and second sensing means comprising first and second coils on spaced axes generally parallel to each other and to said predetermined plane.

Claim 5

Dependent Claim 53 words

In a system as defined in claim 3, said vehicle being movable in said desired path in a horizontal direction on a generally horizontal support surface and said elongated cable being horizontal and in proximity to said surface, said predetermined plane being vertical and said first and second coils having generally vertical axes.

Claim 6

Dependent Claim 55 words

In a system as defined in claim 3, said comparison means comprising a phase sensitive detector, means for applying said first and second signals in phase opposition to said phase sensitive detector, and means responsive to at least one of said first and second signals to apply a reference signal to said phase sensitive detector.

Claim 7

Dependent Claim 58 words

In a system as defined in claim 5, means for applying a pair of test signals to said coils at a pair of frequencies differing from each other and from said certain frequency, and means for responding to the absence of difference frequency components at the output of said phase sensitive detector to indicate malfunction of the system.

Claim 8

Dependent Claim 31 words

In a system as defined in claim 1, means including logic circuitry for responding to the absence of either of said first and second signals to indicate malfunction of the system.

Claim 9

Dependent Claim 36 words

In a system as defined in claim 1, said emitter means being operative for developing an electromagnetic field along said elongated guide, and said reception means being operative to measure the gradient of said electromagnetic field.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1975-06-13	1975-12-13	1976-06-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1979-06-13	1979-12-13	1980-06-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1983-06-13	1983-12-13	1984-06-13	$7700.00	Window Closed / Lapsed

Vehicle guidance systems

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