Antiskid brake control

Claim 2

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for a front vehicle wheel set and at least one rear vehicle wheel set under the control of an operator, means to modify the operatorcontrolled fluid pressure applied to the brakes of one wheel set, a switch for controlling the operation of said pressure modifying means, said switch actuating said pressure-modifying means upon receipt of an activating signal and deenergizing said pressuremodifying means upon receipt of an inhibiting signal, means for generating said activating and inhibiting signals comprising means for generating a first pulse signal, the frequency of which is a function of the rotational velocity of at least one wheel of one of said wheel sets, means for counting said first pulse signal and for delivering to and maintaining at said switch an inhibiting signal upon the completion of a predetermined count, means for generating a second pulse signal having a frequency which is a function of at least one wheel of the other wheel set, means for counting said second pulse signal and for delivering to said switch an activating signal upon the completion of a predetermined count, said counting means being so arranged that said inhibiting signal will be delivered to said switch before said activating signal, except when the frequency of said first pulse signal is less than the frequency of said second pulse signal by a predetermined amount.

Claim 3

The braking system, according to claim 1 together with means responsive to a decrease in the frequency of said second pulse signal below a predetermined amount for delivering an override signal to said switch to maintain said pressure-modifying means deenergized.

Claim 4

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for a front vehicle wheel set and at least one rear vehicle wheel set under the control of an operator, means to modify the operator-controlled fluid pressure applied to the brakes of said rear wheel set, a bistable switching means responsive to set and reset signals to respectively energize and deenergize said pressure-modifying means, a first counting means responsive to input signals representative of rear wheel rotational speed to provide a first counter output pulse indicative of a predetermined count, a second counting means responsive to input signals representative of front wheel rotational speed to provide a second counter output pulse indicative of a predetermined count, said two predetermined counts differing by at least one count, a circuit connecting the output of one of said first counter means to said bistable switch means and to the input of said first counter means to simultaneously reset and inhibit setting of said bistable switch means and to block receipt by said first counter means of further associated wheel roTation input signals, a circuit connecting the output of said second counter means to the set input of said bistable switch means and to a reset circuit for all said counting means to switch said bistable switch means, when uninhibited, to set condition and to reset all said counting means to a start of count condition.

Claim 5

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for a front vehicle wheel set and at least one rear vehicle wheel set under the control of an operator, means to modify the operator-controlled fluid pressure applied to the brakes of said rear wheel set, a bistable switching means responsive to set and reset signals to respectively energize and deenergize said pressure-modifying means, a first counting means responsive to input signals representative of rear wheel rotational speed to provide a first counter output pulse indicative of a predetermined count, a second counting means responsive to input signals representative of front wheel rotational speed to provide a second counter output pulse indicative of a predetermined count, said two predetermined counts differing by at least one count, a circuit connecting the output of one of said first counter means to said bistable switch means and to the input of said first counter means to simultaneously reset and inhibit setting of said bistable switch means and to block receipt by said first counter means of further associated wheel roTation input signals, a circuit connecting the output of said second counter means to the set input of said bistable switch means and to a reset circuit for all said counting means to switch said bistable switch means, when uninhibited, to set condition and to reset all said counting means to a start of count condition.

Claim 6

In a brake system as defined in claim 3, a branch output circuit connecting said second counter means to the reset circuit of said bistable switch and including a time-delayed circuit to enable complete inhibition of operation of said pressure-modifying means in the event said second counter means provides output pulses lower than at a predetermined rate.

Claim 7

In a vehicle having a front ground-engaging wheel set and at least one rearwardly disposed ground-engaging wheel set, at least one of said wheel sets having brakes to which pressurized fluid is supplied under the control of an operator, means to modify the operator-controlled fluid pressure applied to the brakes of said one wheel set comprising a switch for controlling the operation of said pressure-modifying means, said switch actuating said pressure-modifying means upon receipt of an activating signal and deenergizing said pressure-modifying means upon receipt of an inhibiting signal, means for generating said activating and inhibiting signals comprising means for generating a first pulse signal, the frequency of which is a function of the rotational velocity of at least one wheel of one of said wheel sets, means for counting said first pulse signal and for delivering to and maintaining at said switch an inhibiting signal upon the completion of a predetermined count, means for generating a second pulse signal having a frequency which is a function of at least one wheel of the other wheel set, means for counting said second pulse signal and for delivering to said switch an activating signal upon the completion of a predetermined count, said counting means being so arranged that said inhibiting signal will be delivered to said switch before said activating signal, except when the frequency of said first pulse signal is less than the frequency of said second pulse signal by a predetermined amount.

Claim 8

In a vehicle having a front ground-engaging wheel set and at least one rearwardly disposed ground-engaging wheel set, at least one of said wheel sets having brakes to which pressurized fluid is supplied under the control of an operator, means to modify the operator-controlled fluid pressure applied to the brakes of said one wheel set comprising a switch for controlling the operation of said pressure-modifying means, said switch actuating said pressure-modifying means upon receipt of an activating signal and deenergizing said pressure-modifying means upon receipt of an inhibiting signal, means for generating said activating and inhibiting signals comprising means for generating a first pulse signal, the frequency of which is a function of the rotational velocity of at least one wheel of one of said wheel sets, means for counting said first pulse signal and for delivering to and maintaining at said switch an inhibiting signal upon the completion of a predetermined count, means for generating a second pulse signal having a frequency which is a function of at least one wheel of the other wheel set, means for counting said second pulse signal and for delivering to said switch an activating signal upon the completion of a predetermined count, said counting means being so arranged that said inhibiting signal will be delivered to said switch before said activating signal, except when the frequency of said first pulse signal is less than the frequency of said second pulse signal by a predetermined amount.

Claim 9

The combination according to claim 5, together with means responsive to a decrease in the frequency of one of said pulse signals below a predetermined amount for delivering an override signal to said switch.

Claim 10

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for at least one vehicle wheel set under the control of an operator, means to modify the operator-controlled fluid pressure applied to said brakes comprising, means for generating a first series of pulses, the frequency of which is a function of vehicle speed, means for generating a second series of pulses, the frequency of which is a function of the speed of at least one wheel of said set, means for periodically counting the pulses in each series up to a predetermined number and then repeating said count, the pulse generating and counting means being effective, when the speed of said wheel corresponds to the speed of said vehicle, to complete the count of said second series before completion of the count of said first series and being effective to complete the count of said first series before the completion of the count of said second series when the speed of said wheels decreases a predetermined amount with respect to the speed of said vehicle, and means responsive to the completion of the count of said first series before completion of the count of said second series to limit the pressure applied to the brakes of said wheels.

Claim 11

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for at least one vehicle wheel set under the control of an operator, means to modify the operator-controlled fluid pressure applied to said brakes comprising, means for generating a first series of pulses, the frequency of which is a function of vehicle speed, means for generating a second series of pulses, the frequency of which is a function of the speed of at least one wheel of said set, means for periodically counting the pulses in each series up to a predetermined number and then repeating said count, the pulse generating and counting means being effective, when the speed of said wheel corresponds to the speed of said vehicle, to complete the count of said second series before completion of the count of said first series and being effective to complete the count of said first series before the completion of the count of said second series when the speed of said wheels decreases a predetermined amount with respect to the speed of said vehicle, and means responsive to the completion of the count of said first series before completion of the count of said second series to limit the pressure applied to the brakes of said wheels.

Claim 12

The brake system according to claim 7 together with means for inhibiting the action of said last-mentioned means when the vehicle speed is below a predetermined value.

Claim 13

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for at least one vehicle wheel set under the control of an operatOr, means to modify the operator-controlled fluid pressure applied to said brakes comprising means for generating a first series of pulses, the frequency of which is a function of the vehicle speed, means for generating second and third series of pulses, the frequency of each which is a function of the speed of at least one wheel, of said set, means for periodically counting the pulses in each series up to a predetermined amount and then repeating said count, the pulse generating and counting means being effective, when the speed of said wheels corresponds to the speed of said vehicle, to complete the count of said second and third series before completion of the count of said first series and being effective to complete the count of said first series before completion of the count of said second and third series when the speed of said wheels decreases a predetermined amount with respect to the speed of said vehicle, and means responsive to the completion of the count of said first series before the completion of the count of said second and third series to relieve the pressure applied to said brakes.

Claim 14

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for at least one vehicle wheel set under the control of an operatOr, means to modify the operator-controlled fluid pressure applied to said brakes comprising means for generating a first series of pulses, the frequency of which is a function of the vehicle speed, means for generating second and third series of pulses, the frequency of each which is a function of the speed of at least one wheel, of said set, means for periodically counting the pulses in each series up to a predetermined amount and then repeating said count, the pulse generating and counting means being effective, when the speed of said wheels corresponds to the speed of said vehicle, to complete the count of said second and third series before completion of the count of said first series and being effective to complete the count of said first series before completion of the count of said second and third series when the speed of said wheels decreases a predetermined amount with respect to the speed of said vehicle, and means responsive to the completion of the count of said first series before the completion of the count of said second and third series to relieve the pressure applied to said brakes.