Single fluid booster and system

Claim 2

In a vehicle braking system having a fluid reservoir, a primary fluid pressure pump, a secondary fluid pressure pump actuated upon failure of said primary pump, and a brake booster communicated to said primary and secondary pump: said brake booster having an inlet communicated to each of said pumps, an outlet, and operator-actuated valve means controlling fluid communication between said inlet and outlet to effect a brake application; means responsive to failure of said primary pump to actuate said secondary pump; and control valve means communicated to the outlet of each of said pumps and responsive to decrease of the fluid pressure output of said primary pump and resultant actuation of said secondary pump to shift from a first position permitting fluid communication through said outlet to a second position blocking fluid communication through said outlet; said control valve means including a valve element and a differential pressure responsive piston for actuating said valve element; one face of said piston being communicated to the outlet of said secondary pump, whereby upon failure of said primary pump and subsequent actuation of said secondary pump said control valve means shifts from said first position to said second position.

Claim 3

The invention of claim 1: said control valve means in said second position diverting flow of fluid from said outlet to said reservoir.

Claim 4

The invention of claim 1: said control valve means in said second position diverting flow of fluid from said outlet port to said reservoir.

Claim 5

The invention of claim 1: said valve element including a surface exposed to the fluid pressure level communicated to said outlet, said surface having an effective area less than the effective area of said piston face communicated to the outlet of said primary pump whereby said control valve means is maintained in said first position when the fluid pressure level communicated to the outlet port equals the fluid pressure output of said primary fluid pressure pump.

Claim 6

The invention of claim 4: said control valve means including a housing defining a compartment therewithin, a pair of valve seating members dividing said compartment into first, second, and third sections, said first section being communicated to said outlet, said second section having an inlet to permit fluid communication into said second section, said third section being communicated to said reservoir; said valve element engaging one of said valve seats to prevent communication between the second and third section when the control valve means is disposed in the first position, said valve element engaging the other valve seat to prevent communication between said first and second sections when said control valve means is disposed in said second position.

Claim 7

In a vehicle braking system having a fluid reservoir, a primary fluid pressure pump, a secondary fluid pressure pump actuated upon failure of said primary pump, and a brake booster communicated to said primary and secondary pumps; said brake booster having an inlet communicated to each of said pumps, an outlet and operator-actuated valve means controlling fluid communication between said inlet and outlet to effect a brake application; means responsive to failure of said primary pump to actuate said secondary pump; and control valve means communicated to the outlet of each of said pumps and responsive to decrease of the fluid pressure output of said primary pump and resultant actuation of said secondary pump to shift from a first position permitting fluid communication through said outlet to a second position blocking fluid communication through said outlet; said control valve means including a housing defining a bore therewithin, means dividing said bore into a pair of compartments, one of said compartments being communicated to said outlet port and to said reservoir, a pressure differential responsive piston mounted in the other compartment dividing the latter into a first section communicated to said primary fluid pressure pump and a second section communicated to said secondary fluid pressure pump, a valve element mounted in said one compartment and operably connected to said piston whereby movement of said piston moves said valve element to a position diverting fluid flow through said outlet to said reservoir.

Claim 8

In a vehicle braking system having a fluid reservoir, a primary fluid pressure pump, a secondary fluid pressure pump actuated upon failure of said primary pump, and a brake booster communicated to said primary and secondary pumps; said brake booster having an inlet communicated to each of said pumps, an outlet and operator-actuated valve means controlling fluid communication between said inlet and outlet to effect a brake application; means responsive to failure of said primary pump to actuate said secondary pump; and control valve means communicated to the outlet of each of said pumps and responsive to decrease of the fluid pressure output of said primary pump and resultant actuation of said secondary pump to shift from a first position permitting fluid communication through said outlet to a second position blocking fluid communication through said outlet; said control valve means including a housing defining a bore therewithin, means dividing said bore into a pair of compartments, one of said compartments being communicated to said outlet port and to said reservoir, a pressure differential responsive piston mounted in the other compartment dividing the latter into a first section communicated to said primary fluid pressure pump and a second section communicated to said secondary fluid pressure pump, a valve element mounted in said one compartment and operably connected to said piston whereby movement of said piston moves said valve element to a position diverting fluid flow through said outlet to said reservoir.

Claim 9

The invention of claim 6: said control valve means further including a pair of valve seats dividing said one compartment into a first section communicated to said outlet, a second section, and a third section communicated to said reservoir, said piston moving said valve element from said first piston defined by sealing engagement of said valve element with one of said valve seats to prevent fluid communication to said reservoir to said second piston defined by engagement of said valve element with the other valve seat to prevent fluid communication to said outlet port.

Claim 10

In a vehicle braking system having a fluid reservoir, a primary fluid pressure pump, a secondary fluid pressure pump actuated upon failure of said primary pump, and a brake booster communicated to said primary and secondary pumps: said brake booster including a housing having an inlet communicated to each of said pumps, an outlet, an exhaust communicated to said reservoir, fluid pressure responsive means for effecting a brake application, operator-actuated valve means shiftable from a first condition venting said fluid pressure responsive means to said exhaust and communicating substantially all of the fluid flow through said inlet to said outlet to a second position terminating fluid communication between said exhaust and said fluid pressure responsive means and initiating fluid communication between the latter and said inlet to effect a brake application, and means responsive to failure of said primary pump to actuate said secondary pump; and control valve means including a pressure differential responsive piston comparing the fluid pressure output of said primary and secondary pumps, and a Valve element operated by said piston to divert flow of fluid from said outlet to said reservoir upon decrease of the fluid pressure output of said primary pump and subsequent increase of the fluid pressure output of said secondary pump.

Claim 11

In a vehicle braking system having a fluid reservoir, a primary fluid pressure pump, a secondary fluid pressure pump actuated upon failure of said primary pump, and a brake booster communicated to said primary and secondary pumps: said brake booster including a housing having an inlet communicated to each of said pumps, an outlet, an exhaust communicated to said reservoir, fluid pressure responsive means for effecting a brake application, operator-actuated valve means shiftable from a first condition venting said fluid pressure responsive means to said exhaust and communicating substantially all of the fluid flow through said inlet to said outlet to a second position terminating fluid communication between said exhaust and said fluid pressure responsive means and initiating fluid communication between the latter and said inlet to effect a brake application, and means responsive to failure of said primary pump to actuate said secondary pump; and control valve means including a pressure differential responsive piston comparing the fluid pressure output of said primary and secondary pumps, and a Valve element operated by said piston to divert flow of fluid from said outlet to said reservoir upon decrease of the fluid pressure output of said primary pump and subsequent increase of the fluid pressure output of said secondary pump.

Claim 12

The invention of claim 8: said control valve means including a housing defining a bore therewithin; means dividing said bore into a pair of compartments, a pair of valve seats dividing one of said compartments into a first section communicated to said outlet, a second section, and a third section communicated to said reservoir, said valve element being slidably mounted for engagement with each of said seats, said piston being mounted in the other compartment and dividing the latter into a first section communicated with said primary pump and a second section communicated to said secondary pump, said piston shifting said valve element from engagement with one of said seats preventing communication to said reservoir to a position preventing communication to said outlet and permitting communication from said second section to said reservoir upon failure of said primary pump and actuation of said secondary pump.