Brake system

Claim 2

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for front and rear vehicle wheel sets under operator control, means to modify the operator controlled fluid pressure supplied to the brakes of one of said wheel sets comprising, first means operable in response to a first predetermined decrease in the velocity of at least one of the wheels of said one set with respect to the velocity of at least one of the wheels of the other set to limit the fluid pressure applied to the brakes of said one wheel set, and second means operable in response to a second and greater decrease in the velocity of at least one of the wheels of said one set with respect to the velocity of at least one of the wheels of said other set to decrease the fluid pressure applied to the brakes of said one wheel set.

Claim 3

The brake system according to claim 1 wherein said first means includes a normally open valve interposed between said source and the brakes of said one wheel set, and means responsive to said first predetermined decrease in the velocity of the wheels of said one set with respect to the velocity of the wheels of said other set to close said valve.

Claim 4

The brake system according to claim 2 wherein said second means includes a bleed valve interposed between said normally open valve and the brakes of said one wheel set, and means responsive to said second greater decrease in the velocity of the wheels of said one set with respect to the velocity of the wheels of said other set to shift said bleed valve to reduce the pressure applied to the brakes of said one wheel set.

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 supplied to the brakes of one of said wheel sets comprising, means for generating a signal which is a function of the rotational velocity of at least one of the wheels of the other set, means for generating second and third signals each of which is proportional to the velocity of at least one of the wheels of said one set, means for detecting a difference between said first and second signals means for detecting a difference between first and third signals, means responsive to a predetermined detected difference between said first and second signals to limit the fluid pressure applied to the brakes of said one wheel set, and additional means operable in response to a predetermined detected difference between said first and third signals operable to decrease the fluid pressure applied to the brakes of said one wheel set.

Claim 6

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 supplied to the brakes of one of said wheel sets comprising, means for generating a signal which is a function of the rotational velocity of at least one of the wheels of the other set, means for generating second and third signals each of which is proportional to the velocity of at least one of the wheels of said one set, means for detecting a difference between said first and second signals means for detecting a difference between first and third signals, means responsive to a predetermined detected difference between said first and second signals to limit the fluid pressure applied to the brakes of said one wheel set, and additional means operable in response to a predetermined detected difference between said first and third signals operable to decrease the fluid pressure applied to the brakes of said one wheel set.

Claim 7

The brake system according to claim 4 wherein said other wheel set is said front wheel set and said one wheel set is disposed rearwardly of said other wheel set.

Claim 8

The system according to claim 5 wherein said vehicle is a tractor-trailer and wherein said one wheel set and said other wheel set are both on the tractor.

Claim 9

The system according to claim 5 wherein the vehicle is a tractor-trailer and wherein said one wheel set is on the trailer and said other wheel set is on the tractor.

Claim 10

The system according to claim 4 wherein said vehicle is a tractor-trailer unit, wherein said other wheel set is a dirigible set at the front of the tractor, and wherein there are a pair of said rear wheel sets, one on said tractor and one on said trailer, and wherein there is a distinct one of said fluid pressure modifying means associated with each of said rear wheel sets, each operable to detect the velocity thereof relative to the velocity of said front wheel set and to independently control the fluid pressure applied to the brakes thereof in accord with the detected relative velocity.

Claim 11

In combination with a vehicle braking system having a source of fluid applied under pressure under operator control, selectively operable fluid pressure actuated brakes for a front wheel set and at least one rearwardly disposed wheel set, first and second conduit means connecting said source to the front and rear brakes, respectively, to transmit pressurized fluid from said source under operator control to said brakes, the improvement comprising, transducer means mounted adjacent to each wheel of said front and rearward wheel sets for generating first electrical signals each having a frequency proportional to the rotational velocity of the associated wheels, means for converting each of said first signals to proportionately variable amplitude second signals, first means for combining the two of said second signals indicative of the rotational velocity of the front wheels and for producing a first reference output which is representative of the rotational velocity of the front wheel set, second means for combining the two of said second signals indicative of the rotational velocity of the rear wheels and for producing second and third outputs of different magnitude and each indicative of the rotational velocity of the rear wheel set, means to compare said first and second outputs to produce a first control signal only when said second output differs from said first output by a predetermined amount, means to compare said first and third outputs to produce a second control signal only when said third output differs from said first output by a predetermined amount, first means responsive to said first control signal and operable during braking of all wheel sets to isolate said rear brakes from said fluid source and thereby hold constant the developed pressure within said brakes, and second means responsive to said second control signal and operable to reduce at a slow and controlled rate said developed pressure at said rear brakes.

Claim 12

In combination with a vehicle braking system having a source of fluid applied under pressure under operator control, selectively operable fluid pressure actuated brakes for a front wheel set and at least one rearwardly disposed wheel set, first and second conduit means connecting said source to the front and rear brakes, respectively, to transmit pressurized fluid from said source under operator control to said brakes, the improvement comprising, transducer means mounted adjacent to each wheel of said front and rearward wheel sets for generating first electrical signals each having a frequency proportional to the rotational velocity of the associated wheels, means for converting each of said first signals to proportionately variable amplitude second signals, first means for combining the two of said second signals indicative of the rotational velocity of the front wheels and for producing a first reference output which is representative of the rotational velocity of the front wheel set, second means for combining the two of said second signals indicative of the rotational velocity of the rear wheels and for producing second and third outputs of different magnitude and each indicative of the rotational velocity of the rear wheel set, means to compare said first and second outputs to produce a first control signal only when said second output differs from said first output by a predetermined amount, means to compare said first and third outputs to produce a second control signal only when said third output differs from said first output by a predetermined amount, first means responsive to said first control signal and operable during braking of all wheel sets to isolate said rear brakes from said fluid source and thereby hold constant the developed pressure within said brakes, and second means responsive to said second control signal and operable to reduce at a slow and controlled rate said developed pressure at said rear brakes.

Claim 13

In a vehicle brake system in which the brakes for a forward vehicle wheel set and at least one rearwardly disposed vehicle wheel set are energized by pressurized fluid normally supplied from a pressure source under the control of an operator, means to modify the operator controlled fluid pressure supplied to the brakes of one of said wheel sets comprising means for generating a signal which is a function solely of the rotational velocity of at least one of the wheels of the other set, means for generating a second and independent signal which is proportional only to the velocity of at least one of the wheels of said one set, comparator means, means for feeding each of said signals, unmodified by the other, to said comparator means, said comparator means generating a control signal only when the speed of the wheel of the one set is less than the speed of the wheel of said other set, said comparator means being ineffective to generate a control signal when the speed of the wheel of said other set is equal to or less than the speed of the wheel of said one set, and means responsive to said control signal to prevent the application of further fluid pressure to the brakes of said one wheel set while maintaining the brakes of said one wheel set energized whenever the brakes of the other set are energized.

Claim 14

In a vehicle brake system in which the brakes for a forward vehicle wheel set and at least one rearwardly disposed vehicle wheel set are energized by pressurized fluid normally supplied from a pressure source under the control of an operator, means to modify the operator controlled fluid pressure supplied to the brakes of one of said wheel sets comprising means for generating a signal which is a function solely of the rotational velocity of at least one of the wheels of the other set, means for generating a second and independent signal which is proportional only to the velocity of at least one of the wheels of said one set, comparator means, means for feeding each of said signals, unmodified by the other, to said comparator means, said comparator means generating a control signal only when the speed of the wheel of the one set is less than the speed of the wheel of said other set, said comparator means being ineffective to generate a control signal when the speed of the wheel of said other set is equal to or less than the speed of the wheel of said one set, and means responsive to said control signal to prevent the application of further fluid pressure to the brakes of said one wheel set while maintaining the brakes of said one wheel set energized whenever the brakes of the other set are energized.

Claim 15

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source under operator control to the brakes for at least one wheel set of a vehicle having at least two wheel sets, means to modify the operator controlled fluid pressure supplied to the brakes of said one of said wheels comprising, first means operable during brake application to generate a first control signal in response to a first predetermined decrease in the velocity of at least one of the wheels of said one set with respect to the velocity of at least one of the wheels of another set and second means operable during brake application to generate a second control signal in response to a second and greater decrease in the velocity of at least one of the wheels of said one set with respect to the velocity of at least one of the wheels of another set and means responsive to the sequential generation of said first and second signals to decrease the fluid pressure applied to the brakes of said one wheel set.

Claim 16

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source under operator control to the brakes for at least one wheel set of a vehicle having at least two wheel sets, means to modify the operator controlled fluid pressure supplied to the brakes of said one of said wheels comprising, first means operable during brake application to generate a first control signal in response to a first predetermined decrease in the velocity of at least one of the wheels of said one set with respect to the velocity of at least one of the wheels of another set and second means operable during brake application to generate a second control signal in response to a second and greater decrease in the velocity of at least one of the wheels of said one set with respect to the velocity of at least one of the wheels of another set and means responsive to the sequential generation of said first and second signals to decrease the fluid pressure applied to the brakes of said one wheel set.

Claim 17

In a vehicle brake system in which in its normal mode of operation pressurized fluid is supplied from a pressure source under operator control to actuate the brakes for at least one wheel set of a vehicle having at least two wheel sets, means to modify the operator''s control of the fluid pressure supplied to the brakes of said one of said wheel sets comprising means for generating first and second wheel velocity indicative signals, means operative in response to said first and second signals for producing a first type of control signal when the magnitudes of said first and second wheel velocity indicative signals differ by a first amount and for producing a second and different type of control signal when the magnitudes of said first and second wheel velocity indicative signals differ by a second and different amount, means operative while the operator controlled fluid pressure is supplied to the brakes of said one wheel set and responsive to said first type of control signal to establish a first modified mode of operation of said brake system and responsive to said second type of coNtrol system for establishing a second modified mode of operation of said brake system.

Claim 18

In a vehicle brake system in which in its normal mode of operation pressurized fluid is supplied from a pressure source under operator control to actuate the brakes for at least one wheel set of a vehicle having at least two wheel sets, means to modify the operator''s control of the fluid pressure supplied to the brakes of said one of said wheel sets comprising means for generating first and second wheel velocity indicative signals, means operative in response to said first and second signals for producing a first type of control signal when the magnitudes of said first and second wheel velocity indicative signals differ by a first amount and for producing a second and different type of control signal when the magnitudes of said first and second wheel velocity indicative signals differ by a second and different amount, means operative while the operator controlled fluid pressure is supplied to the brakes of said one wheel set and responsive to said first type of control signal to establish a first modified mode of operation of said brake system and responsive to said second type of coNtrol system for establishing a second modified mode of operation of said brake system.