Vehicle brake control system having a plurality of master cylinders which are separately actuatable for different braking operations while being jointly actuatable for emergency braking

Claim 2

A brake control system for a vehicle which has at least a first brake means that is applied by transmitting hydraulic pressure thereto, comprising: first and second master cylinders each having an outlet and each having an actuator means for generating hydraulic pressure at said outlet thereof in response to a brake signal, a first check valve connected to said first brake means and to both of said first and second master cylinder outlets and having valve means for transmitting hydraulic pressure to said first brake means from the one of said outlets which has the higher pressure thereat while blocking direct communication between said outlets, manually controllable service brake signal generating means coupled to said first master cylinder actuator means for selectively applying said first brake means by actuation of said first master cylinder without actuation of said second master cylinder, a manually controllable second brake signal generating means coupled to said second master cylinder actuator means for selectively applying said first brake means by actuation of said second master cylinder without actuation of said first master cylinder, and an emergency brake signal generating means coupled to both said first and said second master cylinders for simultaneously actuating both of said master cylinders to apply hydraulic pressure to said first brake means through said first check valve.

Claim 3

The combination defined in claim 1 wherein said manually controllable second brake signal generating means is a retarding brake signal generating means which applies a maximum hydraulic pressure to said first brake means which is less than the maximum hydraulic pressure which may be applied to said first brake means by actuation of said first master cylinder.

Claim 4

A brake control system for a vehicle which has at least a first brake means that is applied by transmitting hydraulic pressure thereto, comprising: first and second master cylinders each having an outlet and each having an actuator means for generating hydraulic pressure at said outlet thereof in response to a braking signal, a first check valve connected to said first brake means and to both of said first and second master cylinder outlets and having valve means for transmitting hydraulic pressure to said first brake means from the one of said outlets which has the higher pressure thereat while blocking direct communication between said outlets, manually controllable service brake signal generating means coupled to said first master cylinder actuator means for selectively applying said first brake means by actuation of said first master cylinder without actuation of said second master cylinder, and an emergency brake signal generating means coupled to both said first and said second master cylinders for simultaneously actuating both of said master cylinders to apply hydraulic pressure to said first brake means through said first check valve, wherein said emergency brake signal generating means comprises a first emergency tank of compressed gas, emergency relay valve means coupled between said first emergency tank and said first and second master cylinder actuator means for applYing gas pressure thereto to actuate said first and second master cylinders, manually controllable means for selectively causing said emergency relay valve means to apply said gas pressure to said first and second master cylinder actuator means, and an inversion valve means coupled to said first emergency air tank and having means for applying gas pressure to both of said master cylinder actuator means independently of said manually controllable means after the gas pressure within said first emergency tank drops to a first predetermined value.

Claim 5

A brake control system for a vehicle which has at least a first brake means that is applied by transmitting hydraulic pressure thereto, comprising: first and second master cylinders each having an outlet and each having an actuator means for generating hydraulic pressure at said outlet thereof in response to a braking signal, a first check valve connected to said first brake means and to both of said first and second master cylinder outlets and having valve means for transmitting hydraulic pressure to said first brake means from the one of said outlets which has the higher pressure thereat while blocking direct communication between said outlets, manually controllable service brake signal generating means coupled to said first master cylinder actuator means for selectively applying said first brake means by actuation of said first master cylinder without actuation of said second master cylinder, and an emergency brake signal generating means coupled to both said first and said second master cylinders for simultaneously actuating both of said master cylinders to apply hydraulic pressure to said first brake means through said first check valve, wherein said emergency brake signal generating means comprises a first emergency tank of compressed gas, emergency relay valve means coupled between said first emergency tank and said first and second master cylinder actuator means for applYing gas pressure thereto to actuate said first and second master cylinders, manually controllable means for selectively causing said emergency relay valve means to apply said gas pressure to said first and second master cylinder actuator means, and an inversion valve means coupled to said first emergency air tank and having means for applying gas pressure to both of said master cylinder actuator means independently of said manually controllable means after the gas pressure within said first emergency tank drops to a first predetermined value.

Claim 6

The combination defined in claim 3 wherein said vehicle has second brake means which are applied by transmitting hydraulic pressure thereto, said combination further comprising a third master cylinder having a hydraulic pressure outlet communicated with said second brake means and having actuator means for generating hydraulic pressure thereat in response to a braking signal, manually controlled cut off means having an open position at which said third master cylinder actuator means is actuated by service brake signal generating means concurrent with actuation of said first master cylinder thereby and having a closed position at which said third master cylinder actuator means is unresponsive to said service brake signal generating means, and emergency means for actuating said third master cylinder actuator means simultaneously with emergency actuation of said first and second master cylinders irrespective of the position of said cut off means.

Claim 7

The combination defined in claim 4 further comprising a second emergency tank of compressed gas and wherein said emergency means for actuating said third master cylinder actuator means supplied compressed gas thereto from said second emergency tank, and wherein said inversion valve means for applying gas pressure to said first and second master cylinder actuator means from said first emergency tank and for applying gas pressure to said third master cylinder actuator means from said second emergency tank only when the pressure within both of said emergency tanks is below said first predetermined value.

Claim 8

The combination defined in claim 3 further comprising a first warning device, and actuating means for energizing said first warning device in response to a drop of pressure in said first emergency tank to a second predetermined value which is greater than said first predetermined value.

Claim 9

The combination defined in claim 6 further comprising means for maintaining said first warning device deactivated while said manually controllable means is actuated.

Claim 10

A brake control system for a vehicle having hydraulic pressure actuated front wheel brakes and rear wheel brakes, comprising: a front master cylinder coupled to said front wheel brakes and having an actuator for applying hydraulic pressure thereto in response to an air pressure signal, a first check valve having an outlet coupled to said rear wheel brakes and having a pair of hydraulic fluid inlets together with means for communicating said outlet with the one of said inlets having the highest fluid pressure thereat while blocking direct communication between said inlets, a service master cylinder coupled to a first of said inlets of said first check valve and having an actuator for applying hydraulic pressure thereto in response to an air pressure signal, a retarder master cylinder coupled to the other of said inlets of said first check valve and having an actuator for applying hydraulic pressure thereto in response to an air pressure signal, a service braking compressed air tank, a front brake emergency compressed air tank, and a rear brake emergency compressed air tank, a service braking relay valve connected between said service braking tank and said service master cylinder and having a control port and means for transmitting air from said service tank to said service master cylinder actuator in response to pressurization of said control port, a manually operable service brake vaLve connected between said service tank and said control port of said service braking relay valve for selectively pressurizing said control port thereof, a retarder braking relay valve connected between said service tank and said retarder master cylinder and having a control port and means for transmitting air from said service tank to said retarder master cylinder actuator in response to pressurization of said control port, a manually operable retarder brake valve connected between said service tank and said control port of said retarder braking relay valve for selectively pressurizing said control port thereof, a front brake relay valve connected between said service tank and said front master cylinder and having a control port and means for transmitting air from said service tank to said front master cylinder actuator in response to pressurization of said control port, a manually operable cut-off valve connected between said control ports of said front brake relay valve and said service braking relay valve and having an open position and a closed position, a front emergency relay valve connected between said front emergency tank and said front master cylinder actuator independently of said front brake valve and having a control port and means for transmitting air from said front emergency tank to said front master cylinder actuator in response to pressurization of said control port, a rear emergency relay valve connected between said rear emergency tank and both of said service master cylinder actuator and said retarder master cylinder actuator independently of said service relay valve and said retarder relay valve and having a control port and means for transmitting air from said rear emergency tank to said service master cylinder actuator and said retarder master cylinder actuator in response to pressurization of said control port, a manually operable emergency brake valve connected between said front and rear emergency tanks and said control ports of said front and rear emergency relay valves for selectively pressurizing said control ports thereof, and inversion valve means connected between said front and rear emergency tanks and said control ports of said front and rear emergency relay valves independently of said manually operable emergency brake valve and having means for pressurizing said control ports of said front and rear emergency relay valves when the pressure in both of said front and rear emergency tanks drops to a predetermined value.

Claim 11

A brake control system for a vehicle having hydraulic pressure actuated front wheel brakes and rear wheel brakes, comprising: a front master cylinder coupled to said front wheel brakes and having an actuator for applying hydraulic pressure thereto in response to an air pressure signal, a first check valve having an outlet coupled to said rear wheel brakes and having a pair of hydraulic fluid inlets together with means for communicating said outlet with the one of said inlets having the highest fluid pressure thereat while blocking direct communication between said inlets, a service master cylinder coupled to a first of said inlets of said first check valve and having an actuator for applying hydraulic pressure thereto in response to an air pressure signal, a retarder master cylinder coupled to the other of said inlets of said first check valve and having an actuator for applying hydraulic pressure thereto in response to an air pressure signal, a service braking compressed air tank, a front brake emergency compressed air tank, and a rear brake emergency compressed air tank, a service braking relay valve connected between said service braking tank and said service master cylinder and having a control port and means for transmitting air from said service tank to said service master cylinder actuator in response to pressurization of said control port, a manually operable service brake vaLve connected between said service tank and said control port of said service braking relay valve for selectively pressurizing said control port thereof, a retarder braking relay valve connected between said service tank and said retarder master cylinder and having a control port and means for transmitting air from said service tank to said retarder master cylinder actuator in response to pressurization of said control port, a manually operable retarder brake valve connected between said service tank and said control port of said retarder braking relay valve for selectively pressurizing said control port thereof, a front brake relay valve connected between said service tank and said front master cylinder and having a control port and means for transmitting air from said service tank to said front master cylinder actuator in response to pressurization of said control port, a manually operable cut-off valve connected between said control ports of said front brake relay valve and said service braking relay valve and having an open position and a closed position, a front emergency relay valve connected between said front emergency tank and said front master cylinder actuator independently of said front brake valve and having a control port and means for transmitting air from said front emergency tank to said front master cylinder actuator in response to pressurization of said control port, a rear emergency relay valve connected between said rear emergency tank and both of said service master cylinder actuator and said retarder master cylinder actuator independently of said service relay valve and said retarder relay valve and having a control port and means for transmitting air from said rear emergency tank to said service master cylinder actuator and said retarder master cylinder actuator in response to pressurization of said control port, a manually operable emergency brake valve connected between said front and rear emergency tanks and said control ports of said front and rear emergency relay valves for selectively pressurizing said control ports thereof, and inversion valve means connected between said front and rear emergency tanks and said control ports of said front and rear emergency relay valves independently of said manually operable emergency brake valve and having means for pressurizing said control ports of said front and rear emergency relay valves when the pressure in both of said front and rear emergency tanks drops to a predetermined value.

Claim 12

The combination defined in claim 8 further comprising first warning means activated by a drop of pressure in said service tank to a predetermined value indicative of a need to rely on said emergency braking means, a second warning device activated by a drop of pressure in both said front and rear emergency tanks to a second predetermined value which is above that at which said inversion valve means pressurizes said control ports of said front and rear emergency relays, and means for maintaining said second warning device inactive while said manually operable emergency brake valve is actuated.