Brake system

Claim 2

In a brake system for a vehicle having front and rear brakeequipped wheel sets, an operator-controlled valve, a pressurereducing valve, a main conduit system directly connecting said operator-controlled valve to the brakes for at least one wheel set, an additional conduit system connecting said pressurereducing valve in parallel with said main conduit system between said operator-controlled valve and saId brakes, a control valve interposed in said conduit systems between said pressure-reducing valve and said brakes, normally permitting unrestricted flow between said operator-controlled valve and said brakes, means for generating a signal when the tendency of one or more of said wheels to skid is detected during braking, and means responsive to said signal to shift said control valve to interrupt the connection between said operator-controlled valve and said brakes and connect said brakes to said operator-controlled valve through said pressure-reducing valve.

Claim 3

The combination according to claim 1 together with means to maintain said control valve in its shifted position until the brakes are substantially released by said operator-controlled valve.

Claim 4

The combination according to claim 1 wherein said pressure-reducing valve includes a variable capacity chamber connected through said control valve to said brakes, means responsive to an increase in the pressure supplied by said operator-controlled valve to decrease the volume of said chamber to increase the pressure applied to said brakes, and means responsive to a decrease in the pressure supplied by said operator-controlled valve to vent said chamber and thereby decrease the pressure supplied to said brakes.

Claim 5

In a vehicle brake system in which fluid under pressure is normally supplied from a pressure source to the brakes for front and rear wheel sets through an operator-controlled valve and main brake lines and in which a signal is generated when a tendency of one or more of the wheels of one set to skid is detected during braking: a pressure-reducing valve, means connecting the high-pressure side of said pressure-reducing valve to said main brake lines, an additional control valve movable between a first position in which it permits essentially unrestricted flow in said main brake lines and a second position in which it connects the brakes associated with said one wheel set only to the low-pressure side of said pressure-reducing valve, said valve normally occupying said first position, and means responsive to said signal to shift said valve to said second position.

Claim 6

In a vehicle brake system in which fluid under pressure is normally supplied from a pressure source to the brakes for front and rear wheel sets through an operator-controlled valve and main brake lines and in which a signal is generated when a tendency of one or more of the wheels of one set to skid is detected during braking: a pressure-reducing valve, means connecting the high-pressure side of said pressure-reducing valve to said main brake lines, an additional control valve movable between a first position in which it permits essentially unrestricted flow in said main brake lines and a second position in which it connects the brakes associated with said one wheel set only to the low-pressure side of said pressure-reducing valve, said valve normally occupying said first position, and means responsive to said signal to shift said valve to said second position.

Claim 7

The combination according to claim 4 together with means for maintaining the pressure of fluid supplied to the high-pressure side of said pressure-reducing valve at a fixed value until the pressure in said main brake lines has been reduced a predetermined amount.

Claim 8

In a brake system for a vehicle having front and rear brake-equipped wheel sets, an operator-controlled valve, a first conduit system directly connecting said operator-controlled valve to the brakes for one wheel set, a second conduit system connecting said operator-controlled valve to the brakes for the other wheel set, a pressure-reducing valve, means for interposing said pressure-reducing valve in said second conduit system, said conduit systems normally permitting unrestricted flow between said operator-controlled valve and the brakes of both of said wheel sets, means for generating a signal when the tendency of one or more of the wheels of said other set to skid is detected during braking, and means responsive to said signal to actuate said interposing means to interrupt the direct connection between said operator-controlled valve and said brakes of said other wheel set and connect said brakes of said other wheel set to said operator-controlled valve through said pressure-reducing valve whereby said operator-controlled valve remains effective to vary the pressure transmitted to the brakes through both of said conduit systems but at a reduced magnitude to the brakes of said other wheel set.

Claim 9

In a brake system for a vehicle having front and rear brake-equipped wheel sets, an operator-controlled valve, a first conduit system directly connecting said operator-controlled valve to the brakes for one wheel set, a second conduit system connecting said operator-controlled valve to the brakes for the other wheel set, a pressure-reducing valve, means for interposing said pressure-reducing valve in said second conduit system, said conduit systems normally permitting unrestricted flow between said operator-controlled valve and the brakes of both of said wheel sets, means for generating a signal when the tendency of one or more of the wheels of said other set to skid is detected during braking, and means responsive to said signal to actuate said interposing means to interrupt the direct connection between said operator-controlled valve and said brakes of said other wheel set and connect said brakes of said other wheel set to said operator-controlled valve through said pressure-reducing valve whereby said operator-controlled valve remains effective to vary the pressure transmitted to the brakes through both of said conduit systems but at a reduced magnitude to the brakes of said other wheel set.

Claim 10

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 through an operator-controlled valve and in which a signal is generated when a tendency of one or more wheels of one set to skid is detected during braking; a pressure-reducing valve adapted to be sElectively connected in series with the brakes associated with said one set of wheels, means responsive to said signal to interrupt the connection between said operator-controlled valve and the brakes associated with said one wheel set and connect said last-mentioned brakes to said operator-controlled valve through said pressure-reducing valve, means for maintaining said pressure-reducing valve in series with the brakes associated with said one wheel set until the brakes are essentially fully released, and means for restoring the connection between said operator-controlled valve and the brakes associated with said one wheel set when the fluid pressure delivered by said operator-controlled valve exceeds a predetermined value.

Claim 11

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 through an operator-controlled valve and in which a signal is generated when a tendency of one or more wheels of one set to skid is detected during braking; a pressure-reducing valve adapted to be sElectively connected in series with the brakes associated with said one set of wheels, means responsive to said signal to interrupt the connection between said operator-controlled valve and the brakes associated with said one wheel set and connect said last-mentioned brakes to said operator-controlled valve through said pressure-reducing valve, means for maintaining said pressure-reducing valve in series with the brakes associated with said one wheel set until the brakes are essentially fully released, and means for restoring the connection between said operator-controlled valve and the brakes associated with said one wheel set when the fluid pressure delivered by said operator-controlled valve exceeds a predetermined value.

Claim 12

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for a front wheel set and at least one rear vehicle wheel set through an operator-controlled valve and in which a signal is generated when a tendency of one or more of the wheels of one set to skid is detected during braking; a pressure-reducing valve adapted to be selectively connected in series with said operator-controlled valve and with the brakes associated with said one set of wheels, and means responsive to said signal to interrupt the connection between said operator-controlled valve and the brakes associated with said one wheel set and connect said last-mentioned brakes to said operator-controlled valve through said pressure-reducing valve whereby the pressure applied to said brakes at said one wheel set is a function of the pressure delivered through said operator-controlled valve.

Claim 13

In a vehicle brake system in which pressurized fluid is normally supplied from a pressure source to the brakes for a front wheel set and at least one rear vehicle wheel set through an operator-controlled valve and in which a signal is generated when a tendency of one or more of the wheels of one set to skid is detected during braking; a pressure-reducing valve adapted to be selectively connected in series with said operator-controlled valve and with the brakes associated with said one set of wheels, and means responsive to said signal to interrupt the connection between said operator-controlled valve and the brakes associated with said one wheel set and connect said last-mentioned brakes to said operator-controlled valve through said pressure-reducing valve whereby the pressure applied to said brakes at said one wheel set is a function of the pressure delivered through said operator-controlled valve.

Claim 14

The combination according to claim 8 together with means for maintaining said pressure-reducing valve in series with the brakes associated with the said one wheel set until the brakes are essentially released.