Trailer sway-control and braking system
First Claim
1. Apparatus for selectively applying the brakes of a trailer while being towed by a towing vehicle comprising:
- first means for sensing lateral oscillatory motion of said trailer and for generating separate right and left acceleration signals in response to right and left acceleration, respectively of said trailer,second means for producing a sway-inhibiting signal in response to both of said right and left acceleration signals which successively occur in a time shorter than a predetermined period of time,third means for producing a brake control signal in response to said sway-inhibiting signal,said second means including two signal-generating circuits responsive to said right and left accelerating signals, respectively, to produce two logic signals, respectively, means for combining said logic signals to produce a single sway-inhibiting signal only when said logic signals occur simultaneously within said period of time said logic signals being in the form of unidirectional voltages, said combining means being responsive to simultaneous occurrence thereof to produce said sway-inhibiting signal only when the combined unidirectional voltages exceed a predetermined magnitude, said combining means being a logic AND circuit having two input circuits and an output circuit, said two input circuits being connected to said two signal-generating circuits, respectively, to receive the logic signals thereof, each signal-generating circuit including a signal-holding circuit which maintains said logic signal for a predetermined time interval and terminates said logic signal after such time interval, each said signal-holding circuit including a charging capacitor and resistor in parallel, each signal-generating circuit having input and output circuits, said first means including two switch devices individually coupled to the input circuits, respectively, of said signal-generating circuits and being actuable in response to lateral motion of said trailer, said output circuits, respectively, being connected to the input circuits of said logic AND circuit, each of said signal-generating circuits including two series coupled operational amplifiers, a source of threshold potential being connected to one input terminal of each amplifier, the other input terminal of the first amplifier being connected to one of said switch devices and the other input terminal of the second amplifier being coupled to the output terminal of the first amplifier, said capacitor having one side connected to said other input terminal of said second amplifier, and said logic AND circuit including a resistance connected between the output terminals of the second amplifiers of the two signal-generating circuits with a tap on said resistance serving as a part of said logic AND circuit.
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Accused Products
Abstract
Apparatus for inhibiting sway and for applying the brakes of a trailer includes a sway sensor connected to a frequency-discriminating circuit which senses lateral oscillatory motion of the trailer and which generates separate right and left acceleration signals in response to right and left acceleration, respectively, of the trailer. A circuit produces a sway-inhibiting signal in response to both of said right and left acceleration signals which successively occur in a time shorter than a predetermined period of time. A braking-signal circuit produces a brake control signal in response to the sway-inhibiting signal, this brake control signal being utilized for applying the trailer brakes momentarily to correct for a sway condition.
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Citations
23 Claims
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1. Apparatus for selectively applying the brakes of a trailer while being towed by a towing vehicle comprising:
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first means for sensing lateral oscillatory motion of said trailer and for generating separate right and left acceleration signals in response to right and left acceleration, respectively of said trailer, second means for producing a sway-inhibiting signal in response to both of said right and left acceleration signals which successively occur in a time shorter than a predetermined period of time, third means for producing a brake control signal in response to said sway-inhibiting signal, said second means including two signal-generating circuits responsive to said right and left accelerating signals, respectively, to produce two logic signals, respectively, means for combining said logic signals to produce a single sway-inhibiting signal only when said logic signals occur simultaneously within said period of time said logic signals being in the form of unidirectional voltages, said combining means being responsive to simultaneous occurrence thereof to produce said sway-inhibiting signal only when the combined unidirectional voltages exceed a predetermined magnitude, said combining means being a logic AND circuit having two input circuits and an output circuit, said two input circuits being connected to said two signal-generating circuits, respectively, to receive the logic signals thereof, each signal-generating circuit including a signal-holding circuit which maintains said logic signal for a predetermined time interval and terminates said logic signal after such time interval, each said signal-holding circuit including a charging capacitor and resistor in parallel, each signal-generating circuit having input and output circuits, said first means including two switch devices individually coupled to the input circuits, respectively, of said signal-generating circuits and being actuable in response to lateral motion of said trailer, said output circuits, respectively, being connected to the input circuits of said logic AND circuit, each of said signal-generating circuits including two series coupled operational amplifiers, a source of threshold potential being connected to one input terminal of each amplifier, the other input terminal of the first amplifier being connected to one of said switch devices and the other input terminal of the second amplifier being coupled to the output terminal of the first amplifier, said capacitor having one side connected to said other input terminal of said second amplifier, and said logic AND circuit including a resistance connected between the output terminals of the second amplifiers of the two signal-generating circuits with a tap on said resistance serving as a part of said logic AND circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for selectively applying the brakes of a trailer while being towed by a towing vehicle comprising:
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first means for sensing lateral oscillatory motion of said trailer and for generating separate right and left acceleration signals in response to right and left acceleration, respectively, of said trailer, second means for producing a sway-inhibiting signal in response to both of said right and left acceleration signals which successively occur in a time shorter than a predetermined period of time, third means for producing a brake control signal in response to said sway-inhibiting signal, said second means including two signal-generating circuits responsive to said right and left acceleration signals, respectively, to produce two logic signals, respectively, means for combining said logic signals to produce a single sway-inhibiting signal only when said logic signals occur simultaneously within said predetermined period of time, said logic signals being in the form of unidirectional voltages, said combining means being responsive to simultaneous occurrence thereof to produce said sway-inhibiting signal only when the combined unidirectional voltages exceed a predetermined magnitude, said third means including circuit means for shaping said brake control signal such that it progressively increases in magnitude at a predetermined rate whereby the brakes of said trailer are progressively applied accordingly.
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11. Apparatus for inhibiting sway of a trailer towed by a towing vehicle, said trailer having brakes actuable by an electrical braking circuit, comprising:
sensing means responsive to oscillatory sway having a period of oscillation that occurs within a predetermined period of time for producing a sway-inhibiting signal, signal means responsive to said signal for producing a brake control signal, said brake control signal means having an output circuit connected to said braking circuit for applying said brake control signal thereto to actuate said brakes, said brake control signal means including a current amplifier for amplifying said brake control signal and a current-sensing circuit which produces an overload signal in response to overload current being drawn by said braking circuit for producing a bias which disables said current amplifier. - View Dependent Claims (12, 13, 14)
- 15. Apparatus for selectively applying the brakes of a trailer being towed by a towing vehicle, said brakes including a braking circuit and said towing vehicle carrying manually operable brake-applying means, said apparatus comprising sensing means responsive to oscillatory sway of said trailer having a period of oscillation that occurs within a predetermined period of time for producing a sway-inhibiting signal, circuit means responsive to said sway-inhibiting signal for producing a first brake-actuating signal of predetermined magnitude, said circuit means having an output circuit connected to said braking circuit for applying said first brake-actuating signal thereto to actuate said brakes, manually operable circuit means responsive to operation of said manually operable brake-applying means for generating a brake-applying signal of given magnitude, said circuit means also being responsive to said brake-applying signal of given magnitude to produce a corresponding second brake-actuating signal of less than said predetermined magnitude, said first, second, sway-inhibiting and brake-applying signals being unidirectional potentials, said manually operable circuit means including manually controlled means for varying the magnitude of said brake-applying signal within a range which exceeds said given magnitude, said manually operable circuit means and said manually controlled means including two brake-operating switches on the towing vehicle, one of said switches being cooperatively associated with the towing vehicle brake pedal to initiate production of said brake-applying signal when said pedal is operated and the other of said switches being manually operable to also initiate production of said brake-applying signal, a source of unidirectional supply voltage, each of said switches being series connected between said source and said circuit means, said other switch having a variable resistor in series and cooperatively associated therewith to vary in resistance in relation to manual actuating force applied to said other switch thereby determining the magnitude of said brake-applying signal applied to said circuit means, said circuit means responding to either or both of said sway-inhibiting and brake-applying signals to produce a brake-actuating signal of a magnitude corresponding to the greater of both signals when they occur simultaneously or to one signal occurring independently whereby said trailer brakes may be applied either fully or partially depending upon the magnitudes of said sway-inhibiting and brake-applying signals, said manually operable circuit means further including a first transistor and a charging capacitor connected between the emitter and collector thereof, means for biasing said transistor to a normally conductive state when said one switch is not operated, a resistance series connected between one of said emitter and collector and said source thereby establishing a charging path to said capacitor, first circuit means connected to the base of said transistor for rendering the latter non-conductive in response to actuation of said one switch thereby establishing a charging current to said capacitor, and a signal-carrying circuit connecting said capacitor to said circuit means for applying said brake-applying signal thereto.
- 18. Apparatus for selectively applying the brakes of a trailer being towed by a towing vehicle, said brakes including a braking circuit and said towing vehicle carrying manually operable brake-applying means, said apparatus comprising sensing means responsive to oscillatory sway of said trailer having a period of oscillation that occurs within a predetermined period of time for producing a sway-inhibiting signal, circuit means responsive to said sway-inhibiting signal for producing a first brake-actuating signal of predetermined magnitude, said circuit means having an output circuit connected to said braking circuit for applying said first brake-actuating signal thereto to actuate said brakes, manually operable circuit means responsive to operation of said manually operable brake-applying means for generating a brake-applying signal, said sensing means having an output circuit in which appears said sway-inhibiting signal, said circuit means having an input circuit connected to said output circuit of said sensing means, said manually operable circuit means being connected to said input circuit of said circuit means whereby both said sway-inhibiting and brake-applying signals may be simultaneously or individually applied thereto, said circuit means further including a voltage-follower responsive to said sway-inhibiting and brake-applying signals to reproduce the same signals, and a current amplifier coupled to said voltage-follower to produce said brake control signal.
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22. An electric brake control apparatus for disabling the brakes of a towed vehicle when the towing vehicle is shifted into reverse comprising:
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(a) means for applying the brakes of the towed vehicle from the towing vehicle, (b) means for disabling the applying means when said towing vehicle is shifted into reverse, said applying means including first circuitry for producing a brake-applying signal when the brakes of the towed vehicle are applied, said first circuitry including an amplifier;
said disabling means including second circuitry which is coupled to said amplifier for selectively disabling the latter, said second circuitry including switch means responsive to shifting said towing vehicle into reverse and biasing means which is responsive to activation of said switch means to disable said amplifier. - View Dependent Claims (23)
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Specification