Skid control system

Claim 2

In a skid control system for controlling fluid pressure actuated brakes of at least one wheel of a wheeled vehicle by controlling the fluid pressure to the brakes, said system comprising control means for providing an output signal in response to the detection of a skid condition at the one wheel, first fluid circuit means actuable for actuating the brakes with the magnitude of brake actuation varying with variations in the magnitude of a first fluid pressure in said first circuit means, second fluid circuit means selectively actuable for the vehicle operator for actuating said first fluid circuit means, said second circuit means comprising booster means actuable in response to said second fluid pressure for acting on said first fluid circuit means for varying the pressure in said first circuit means in accordance with selected variations in the magnitude of a second fluid pressure in said second circuit means, source means for providing fluid under pressure to said second circuit means, said second circuit means further comprising modulating means operable by the vehicle operator for selectively varying the magnitude of fluid pressure from said source means for providing said second fluid pressure and skid control means interposed between said modulating means and said booster means and normally not effective for controlling the flow of fluid passing there through to said booster means and responsive to said output signal for controlling the flow of fluid therethrough to said booster means whereby the magnitude of said second fluid pressure from said modulating valve and hence of said first fluid pressure is controlled to inhibit a skid condition.

Claim 3

The system of claim 1 with said skid control means comprising valve means operable upon actuation to rapidly reduce the magnitude of said second fluid pressure and operable upon deactuation to increase the magnitude of said second fluid pressure rapidly to a selected magnitude and then slowly.

Claim 4

The system of claim 1 with said source means having an outlet and a return and wiTh said skid control means comprising an actuating valve actuable to one position in response to actuation of said skid control means for blocking said second fluid pressure from said booster means while relieving the pressure to said booster means.

Claim 5

In a skid control system for controlling fluid pressure actuated brakes of at least one wheel of a wheeled vehicle by controlling the fluid pressure to the brakes, said system comprising control means for providing an output signal in response to the detection of a skid condition at the one wheel, first fluid circuit means actuable for actuating the brakes with the magnitude of brake actuation varying with variations in the magnitude of a first fluid pressure in said first circuit means, second fluid circuit means selectively actuable by the vehicle operator for actuating said first fluid circuit means and for varying the pressure in said first circuit means in accordance with selected variations in the magnitude of a second fluid pressure in said second circuit means, source means for providing fluid under pressure to said second circuit means, said second circuit means further comprising modulating means operable by the vehicle operator for selectively varying the magnitude of fluid pressure from said source means for providing said second fluid pressure and skid control means responsive to said output signal for reducing the magnitude of said second fluid pressure whereby the magnitude of said first fluid pressure is reduced, said skid control means comprising valve means operable upon actuation to rapidly reduce the magnitude of said second fluid pressure and operable upon deactuation to increase the magnitude of said second fluid pressure rapidly to a selected magnitude and then slowly, said valve means comprising check valve means operable for rapidly reducing the magnitude of said second fluid pressure and throttle valve means operable to one condition for causing an increase in magnitude of said second fluid pressure slowly.

Claim 6

In a skid control system for controlling fluid pressure actuated brakes of at least one wheel of a wheeled vehicle by controlling the fluid pressure to the brakes, said system comprising control means for providing an output signal in response to the detection of a skid condition at the one wheel, first fluid circuit means actuable for actuating the brakes with the magnitude of brake actuation varying with variations in the magnitude of a first fluid pressure in said first circuit means, second fluid circuit means selectively actuable by the vehicle operator for actuating said first fluid circuit means and for varying the pressure in said first circuit means in accordance with selected variations in the magnitude of a second fluid pressure in said second circuit means, source means for providing fluid under pressure to said second circuit means, said second circuit means further comprising modulating means operable by the vehicle operator for selectively varying the magnitude of fluid pressure from said source means for providing said second fluid pressure and skid control means responsive to said output signal for reducing the magnitude of said second fluid pressure whereby the magnitude of said first fluid pressure is reduced, said skid control means comprising valve means operable upon actuation to rapidly reduce the magnitude of said second fluid pressure and operable upon deactuation to increase the magnitude of said second fluid pressure rapidly to a selected magnitude and then slowly, said valve means comprising check valve means operable for rapidly reducing the magnitude of said second fluid pressure and throttle valve means operable to one condition for causing an increase in magnitude of said second fluid pressure slowly.

Claim 7

The system of claim 4 with said throttle valve means in said one condition increasing the magnitude of said second fluid pressure in accordance with the magnitude of a bias holding said throttle valve means in said one condition and bias means for slowly varying the magnitude of said bias on said throttle valve means.

Claim 8

The system of claim 5 with said bias means comprising a bias valve having a preselected orifice with the variation in magnitude of said bias determined by the flow of fluid through said orifice.

Claim 9

In a skid control system for controlling fluid pressure actuated brakes of at least one wheel of a wheeled vehicle by controlling the fluid pressure to the brakes, said system comprising control means for providing an output signal in response to the detection of a skid condition at the one wheel, first fluid circuit means actuable for actuating the brakes with the magnitude of brake actuation varying with variations in the magnitude of a first fluid pressure in said first circuit means, second fluid circuit means selectively actuable by the vehicle operator for actuating said first fluid circuit means and for varying the pressure in said first circuit means in accordance with selected variations in the magnitude of a second fluid pressure in said second circuit means, source means for providing fluid under pressure to said second circuit means, said second circuit means further comprising modulating means operable by the vehicle operator for selectively varying the magnitude of fluid pressure from said source means for providing said second fluid pressure and skid control means responsive to said output signal for reducing the magnitude of said second fluid pressure whereby the magnitude of said first fluid pressure is reduced, said second circuit means booster means actuable in response to said second fluid pressure for acting on said first fluid circuit means, said source means having an outlet and a return and with said skid control means comprising an actuatinG valve actuable to one position in response to actuation of said skid control means for blocking said second fluid pressure from said booster means while relieving the pressure to said booster means, said booster means having an inlet and a return path and providing pressure boosting to said second circuit mean when said inlet is subject to fluid pressure and with said skid control means having a second position in which said inlet is connected to said outlet via said modulating means and said return path is connected to said return via said modulating means.

Claim 10

In a skid control system for controlling fluid pressure actuated brakes of at least one wheel of a wheeled vehicle by controlling the fluid pressure to the brakes, said system comprising control means for providing an output signal in response to the detection of a skid condition at the one wheel, first fluid circuit means actuable for actuating the brakes with the magnitude of brake actuation varying with variations in the magnitude of a first fluid pressure in said first circuit means, second fluid circuit means selectively actuable by the vehicle operator for actuating said first fluid circuit means and for varying the pressure in said first circuit means in accordance with selected variations in the magnitude of a second fluid pressure in said second circuit means, source means for providing fluid under pressure to said second circuit means, said second circuit means further comprising modulating means operable by the vehicle operator for selectively varying the magnitude of fluid pressure from said source means for providing said second fluid pressure and skid control means responsive to said output signal for reducing the magnitude of said second fluid pressure whereby the magnitude of said first fluid pressure is reduced, said second circuit means booster means actuable in response to said second fluid pressure for acting on said first fluid circuit means, said source means having an outlet and a return and with said skid control means comprising an actuatinG valve actuable to one position in response to actuation of said skid control means for blocking said second fluid pressure from said booster means while relieving the pressure to said booster means, said booster means having an inlet and a return path and providing pressure boosting to said second circuit mean when said inlet is subject to fluid pressure and with said skid control means having a second position in which said inlet is connected to said outlet via said modulating means and said return path is connected to said return via said modulating means.

Claim 11

The system of claim 7 with said skid control means in said one position connecting said outlet from said source means to said inlet via said modulating means and said return path to said return.

Claim 12

The system of claim 8 for use with a vehicle having front and rear wheels and front and rear wheel brakes, said second circuit means comprising first and second booster means for said front wheel brakes and for said rear wheel brakes, respectively, each connected to said modulating means.

Claim 13

The system of claim 9 with said control means comprising first and second skid control means connected from said modulating means to said first and second booster means, respectively.

Claim 14

The system of claim 10 with said modulating means providing fluid pressures to said first and second booster means varying in a first preselected relation relative to each other up to a preselected pressure and comprising proportioning valve means operable at said preselected pressure in said second circuit means for varying the fluid pressure to said first and second booster means in a second preselected relation.

Claim 15

The system of claim 11 with said first preselected relation providing for similar variations in pressure to said first and second booster means in response to selected actuation of said modulating means, said second preselected relation providing for relatively greater increases in pressure to said first booster means relative to said second booster means.

Claim 16

The system of claim 12 with the front wheel brakes being disc brakes and with the rear wheel brakes being drum brakes, said modulating means comprising metering valve means for holding off the pressure to said first booster means from said modulating valve means until attainment of a different preselected pressure in said second circuit means.

Claim 17

In a skid control system for controlling fluid pressure actuated brakes of at least one brake of a wheeled vehicle which brakes are actuated through a first fluid circuit including a master cylinder for varying the fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinder, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connected to said source and selectively operable by the vehicle operator or varying the fluid pressure at an outlet, a power booster connected to the master cylinder and to said outlet of said modulating valve for varying the actuating force to the master cylinder in accordance with variations in the fluid pressure at said outlet, and skid control means interposed between said outlet of said modulating valve means and said power booster and normally not effective for controlling the flow of fluid pressure therethrough to said power booster and responsive to an incipient skid condition for controlling the flow of fluid therethrough to said power booster whereby the magnitude of the fluid pressure to said power booster and hence of the force to the master cylinder is controlled to inhibit a skid condition.

Claim 18

In a skid control system for controlling fluid pressure actuated brakes of at least one brake of a wheeled vehicle which brakes are actuated through a first fluid circuit including a master cylinder for varying the fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinder, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connected to said source and selectively operable by the vehicle operator or varying the fluid pressure at an outlet, a power booster connected to the master cylinder and to said outlet of said modulating valve for varying the actuating force to the master cylinder in accordance with variations in the fluid pressure at said outlet, and skid control means interposed between said outlet of said modulating valve means and said power booster and normally not effective for controlling the flow of fluid pressure therethrough to said power booster and responsive to an incipient skid condition for controlling the flow of fluid therethrough to said power booster whereby the magnitude of the fluid pressure to said power booster and hence of the force to the master cylinder is controlled to inhibit a skid condition.

Claim 19

The system of claim 14 with said skid control means comprising a valve actuable to relieve the fluid pressure to said power booster and vacuum actuated actuating means responsive to said incipient skid condition for actuating said valve.

Claim 20

The system of claim 14 with said control means comprising valve means actuable to a first condition Upon detection of an incipient skid condition to rapidly reduce the magnitude of pressure on said power booster and actuable to a second condition upon detection of cessation of the incipient skid condition to provide the reapplication of pressure to said power booster rapidly to a preselected pressure and then gradually.

Claim 21

The system of claim 14 with said source being an open center hydraulic system.

Claim 22

The system of claim 14 with said source being a closed center hydraulic system.

Claim 23

In a skid control system for controlling fluid pressure actuated brakes of at least one brake of a wheeled vehicle which brakes are actuated through a first fluid circuit including a master cylinder for varying the fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinder, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connecting to said source and selectively operable by the vehicle operator for varying the fluid pressure at an outlet, a power booster connected to the master cylinder and to said outlet of said modulating valve for varying the actuating force to the master cylinder in accordance with variations in the fluid pressure at said outlet, and skid control means connected to said modulating valve means and to said power booster and responsive to an incipient skid condition to relieve the fluid pressure to said power booster, said skid control means comprising valve means actuable to a first condition upon detection of an incipient skid condition to rapidly reduce the magnitude of pressure on said power booster and actuable to a second condition upon detection of cessation of the incipient skid condition to provide the reapplication of pressure to said power booster rapidly to a preselected pressure and then gradually, said valve means comprising check valve means operable for rapidly reducing the magnitude of the fluid pressure on said power booster and throttle valve means operable to one condition for causing an increase in the fluid pressure slowly.

Claim 24

In a skid control system for controlling fluid pressure actuated brakes of at least one brake of a wheeled vehicle which brakes are actuated through a first fluid circuit including a master cylinder for varying the fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinder, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connecting to said source and selectively operable by the vehicle operator for varying the fluid pressure at an outlet, a power booster connected to the master cylinder and to said outlet of said modulating valve for varying the actuating force to the master cylinder in accordance with variations in the fluid pressure at said outlet, and skid control means connected to said modulating valve means and to said power booster and responsive to an incipient skid condition to relieve the fluid pressure to said power booster, said skid control means comprising valve means actuable to a first condition upon detection of an incipient skid condition to rapidly reduce the magnitude of pressure on said power booster and actuable to a second condition upon detection of cessation of the incipient skid condition to provide the reapplication of pressure to said power booster rapidly to a preselected pressure and then gradually, said valve means comprising check valve means operable for rapidly reducing the magnitude of the fluid pressure on said power booster and throttle valve means operable to one condition for causing an increase in the fluid pressure slowly.

Claim 25

The system of claim 19 with said throttle valve means in said one condition increasing the magnitude of said second fluid pressure in accordance with the magnitude of a bias holding said throttle valve means in said one condition and bias means for slowly varying the magnitude of said bias on said throttle valve means.

Claim 26

The system of claim 20 with said bias means comprising a bias valve having a preselected orifice with the variation in magnitude of said bias determined by the flow of fluid through said orifice.

Claim 27

The system of claim 21 with said bias valve being movable from a normally fixed position to a different actuated position in response to pressure relief to said power booster.

Claim 28

The system of claim 22 with said bias valve being actuated by the fluid pressure at said outlet.

Claim 29

In a skid control system for controlling fluid pressure actuated brakes of at least one brake of a wheeled vehicle which brakes are actuated through a first fluid circuit including a master cylinder for varying the fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinder, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connected to said source and selectively operable by the vehicle operator for varying the fluid pressure at an outlet, a power booster connected to the master cylinder and to said outlet of said modulating valve for varying the actuating force to the master cylinder in accordance with variations in the fluid pressure at said outlet, and skid control means connected to said modulating valve means and to said power booster and responsive to an incipient skid condition to relieve the fluid pressure to said power booster, further comprising manually actuable means having one position for actuating said modulating means via actuation by the vehicle operator and having a second position responsive to loss of pressure from said source for acting directly on the master cylinder to permit actuation of the brakes directly by the vehicle operator said manually means including a linkage assembly providing for an increase in mechanical advantage for operation on the master cylinder when in said second position.

Claim 30

In a skid control system for controlling fluid pressure actuated brakes of at least one brake of a wheeled vehicle which brakes are actuated through a first fluid circuit including a master cylinder for varying the fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinder, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connected to said source and selectively operable by the vehicle operator for varying the fluid pressure at an outlet, a power booster connected to the master cylinder and to said outlet of said modulating valve for varying the actuating force to the master cylinder in accordance with variations in the fluid pressure at said outlet, and skid control means connected to said modulating valve means and to said power booster and responsive to an incipient skid condition to relieve the fluid pressure to said power booster, further comprising manually actuable means having one position for actuating said modulating means via actuation by the vehicle operator and having a second position responsive to loss of pressure from said source for acting directly on the master cylinder to permit actuation of the brakes directly by the vehicle operator said manually means including a linkage assembly providing for an increase in mechanical advantage for operation on the master cylinder when in said second position.

Claim 31

The system of claim 24 with said modulating means providing a reaction force to said manually actuable means resisting actuation with said reaction force increasing with increased pressure at said outlet.

Claim 32

The system of claim 25 with said modulating means providing for increases of said reaction force in response to increases of the pressure at said outlet in accordance with one preselected rate up to a preselected magnitude and at a higher rate at pressures greater than said preselected magnitude.

Claim 33

In a system for controlling fluid pressure actuated brakes of front and rear brakes of a wheeled vehicle which front and rear brake are actuated through first and second fluid circuits including first and second master cylinders, respectively, for varying fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinders, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connected to said source and selectively operable by the vehicle operator for varying the fluid pressure at an outlet, first and second power boosters connected to the first and second master cylinders respectively, and to said outlet of said modulating valve means for varying the actuating force to the first and second master cylinders, respectively, in accordance with variations in the fluid pressure at said outlet, and proportioning valve means operable at a preselected pressure at said outlet for varying the pressure to one of said first and second boosters at a different rate than that to the other.

Claim 34

In a system for controlling fluid pressure actuated brakes of front and rear brakes of a wheeled vehicle which front and rear brake are actuated through first and second fluid circuits including first and second master cylinders, respectively, for varying fluid pressure to the brakes in accordance with variations of an actuating force applied to the master cylinders, said system comprising: a source of fluid pressure providing fluid pressure independently of the vehicle operator, modulating valve means connected to said source and selectively operable by the vehicle operator for varying the fluid pressure at an outlet, first and second power boosters connected to the first and second master cylinders respectively, and to said outlet of said modulating valve means for varying the actuating force to the first and second master cylinders, respectively, in accordance with variations in the fluid pressure at said outlet, and proportioning valve means operable at a preselected pressure at said outlet for varying the pressure to one of said first and second boosters at a different rate than that to the other.

Claim 35

The system of claim 27 with said modulating valve means varying the pressure to said first and second boosters in a first preselected relation up to said preselected pressure and with said proportioning valve means upon actuation varying the fluid pressure to said first and second boosters in a second preselected relation.

Claim 36

The system of claim 28 with said first preselected relation providing for similar variations in pressure to said first and second boosters in response to selected actuation of said modulating means, said second preselected relation providing for relatively greater increases in pressure to said first booster relative to said second booster.

Claim 37

The system of claim 29 with the front wheel brakes being disc brakes and with the rear wheel brakes being drum brakes, said modulating means comprising metering valve means for holding off the pressure to said first booster means until attainment of a different preselected pressure at said outlet.

Claim 38

The system of claim 27 with the front wheel brakes being disc brakes and with the rear wheel brakes being drum brakes, said modulating means comprising metering valve means for holding off the pressure to said first booster means until attainment of a different preselected pressure at said outlet.