Vehicle braking system

Claim 2

A vehicle braking system comprising, in combination, a dual purpose hydraulic accumulator adapted to store hydraulic fluid under pressure and provided with a brake spring adapted to mechanically apply brakes of the vehicle, said brake spring being compressed to relieve said brakes of said mechanical actuation when hydraulic fluid is stored in said accumulator; a vehicle brake mechanism; hydraulic actuator means for operating said brake mechanism; and a metering valve for controllably connecting said hydraulic accumulator to said hydraulic actuator means for normal operation of the braking system.

Claim 3

A vehicle braking system according to claim 1 further comprising safety valve means for connecting said hydraulic accumulator directly to said hydraulic actuator means, independently of said metering valve, for emergency operation of the braking system.

Claim 4

A braking system according to claim 1 for a trailer vehicle adapted to be hitched to a tractor vehicLe in which said metering valve is fitted to the tractor vehicle and said dual purpose hydraulic accumulator, said brake mechanism and said actuator means are fitted to the trailer vehicle, said metering valve having a housing with an inlet port, a brake port and a drain port and containing valve means adapted to selectively and controllably connect said brake port to said drain port or said inlet port, and in which said braking system includes a brake line on said trailer vehicle and connected to said actuator means, first cooperating coupling means for releasably connecting said brake port to said brake line, an accumulator line on said trailer vehicle and connected to said accumulator and second cooperating coupling means for releasably connecting said accumulator line to said metering valve inlet port.

Claim 5

A braking system according to claim 3 in which said first and second cooperating coupling means include trailer mounted coupling heads to which said brake and accumulator lines are attached respectively, tractor-mounted coupling heads respectively cooperable therewith and closure members at least in said trailer-mounted coupling heads and adapted to automatically seal off said trailer-mounted coupling heads when the latter are detached from the tractor-mounted coupling heads and in which the braking system further includes a safety valve arrangement on the trailer vehicle and adapted to interconnect said accumulator and brake lines in the event that the trailer vehicle breaks away from the tractor vehicle.

Claim 6

A braking system according to claim 3 in which said valve means of said metering valve is adapted to control connections between said inlet port and said brake port and between said brake port and said drain port, and in which said metering valve further comprises a brake pressure chamber in said housing connected to said brake port, a control chamber in said housing adapted to be subjected to a control pressure and valve actuating means responsive to the difference between the fluid pressures in said brake pressure chamber and said control chamber for actuating said valve means.

Claim 7

A braking system according to claim 5 in which said valve actuating means comprises piston means slidable in said housing and in which said valve means comprises a first valve seat disposed in said housing between said inlet and brake supports thereof, a second valve seat on said piston means, and a valve closure member cooperable with said first and second valve seats, said second valve seat being connected to said drain port at least when said second seat is spaced from said closure member, said piston means being movable by pressure in said control chamber until said second valve seat engages said closure member, further movement of said piston means lifting said closure member from said first seat to establish communication between said inlet and brake ports.

Claim 8

A braking system according to claim 1 in which said brake spring acts on said brake mechanism in a direction to mechanically operate said mechanism.

Claim 9

A vehicle braking system according to claim 1 further comprising a constant volume hydraulic pump having a pump outlet; hydraulic services adapted to consume hydraulic power; at least one open-center type control valve having an inlet port, a service port and a drain port, said service port being connected to said hydraulic services; and an unloader valve having an inlet port, a pressure port and a drain port, said pressure port being connected to said accumulator, said control valve and said unloader valve being connected in series by their said inlet and drain ports to form a series circuit, said series circuit being connected to said pump outlet, said control valve being adapted to control said hydraulic services and said unloader valve being adapted to load said pump to enable the pump to charge said accumulator and being adapted to switch to a pump unloading state when the accumulator has been charged to a predetermined pressure.

Claim 10

A vehicle braking system acCording to claim 1 further comprising a hydraulic pump having a pump outlet; an unloader valve having an inlet port, a pressure port, a drain port, a valve seat between said inlet port and said drain port and a valve closure member cooperating with said valve seat and movable away from said valve seat responsively to a predetermined pressure applied to said pressure port; means connecting said pump outlet to said inlet port; means connecting said pressure port to said accumulator and means interconnecting said inlet port and said pressure port for charging said accumulator to said predetermined pressure whereupon said valve closure member opens said valve seat to connect said inlet port to said drain port to unload said pump.

Claim 11

A braking system for a trailer vehicle adapted to be hitched to a tractor vehicle comprising a trailer brake mechanism; hydraulic actuator means on said trailer vehicle for operating said trailer brake mechanism; a hydraulic accumulator on said trailer vehicle for storing hydraulic fluid under pressure; a hydraulic pump on said tractor vehicle, said pump having a pump outlet; an unloader valve on said tractor vehicle, said unloader valve having an inlet port, a pressure port, a drain port, a valve seat between said inlet port and said drain port and a valve closure member cooperating with said valve seat and movable away from said valve seat responsively to a predetermined pressure applied to said pressure port; means connecting said pump outlet to said unloader valve inlet port; means connecting said pressure port to said accumulator; means interconnecting said unloader valve inlet port and said pressure port for charging said accumulator to said predetermined pressure whereupon said valve closure member opens said valve seat to connect said unloader valve inlet port to said unloader valve drain port to unload said pump; a metering valve on said tractor vehicle for controllably connecting said hydraulic accumulator to said hydraulic actuator means for normal operation of the braking system, said metering valve having an inlet port, a brake port and a drain port and being adapted to selectively and controllably connect said brake port to said metering valve drain port or said metering valve inlet port; a brake line on said trailer vehicle and connected to said actuator means; first cooperating coupling means for releasably connecting said brake port to said brake line; an accumulator line on said trailer vehicle and connected to said accumulator; and second cooperating coupling means for releasably connecting said accumulator line to said unloader valve pressure port and to said metering valve inlet port.

Claim 12

A braking system for a trailer vehicle adapted to be hitched to a tractor vehicle comprising a trailer brake mechanism; hydraulic actuator means on said trailer vehicle for operating said trailer brake mechanism; a hydraulic accumulator on said trailer vehicle for storing hydraulic fluid under pressure; a hydraulic pump on said tractor vehicle, said pump having a pump outlet; an unloader valve on said tractor vehicle, said unloader valve having an inlet port, a pressure port, a drain port, a valve seat between said inlet port and said drain port and a valve closure member cooperating with said valve seat and movable away from said valve seat responsively to a predetermined pressure applied to said pressure port; means connecting said pump outlet to said unloader valve inlet port; means connecting said pressure port to said accumulator; means interconnecting said unloader valve inlet port and said pressure port for charging said accumulator to said predetermined pressure whereupon said valve closure member opens said valve seat to connect said unloader valve inlet port to said unloader valve drain port to unload said pump; a metering valve on said tractor vehicle for controllably connecting said hydraulic accumulator to said hydraulic actuator means for normal operation of the braking system, said metering valve having an inlet port, a brake port and a drain port and being adapted to selectively and controllably connect said brake port to said metering valve drain port or said metering valve inlet port; a brake line on said trailer vehicle and connected to said actuator means; first cooperating coupling means for releasably connecting said brake port to said brake line; an accumulator line on said trailer vehicle and connected to said accumulator; and second cooperating coupling means for releasably connecting said accumulator line to said unloader valve pressure port and to said metering valve inlet port.

Claim 13

A braking system according to claim 10 in which said first and second cooperating coupling means include trailer mounted coupling heads to which said brake and accumulator lines are attached respectively, tractor-mounted coupling heads respectively cooperable therewith and closure members at least in said trailer-mounted coupling heads and adapted to automatically seal off said trailer-mounted coupling heads when the latter are detached from the tractor-mounted coupling heads and in which the braking system includes a safety valve arrangement on the trailer vehicle and adapted to interconnect said accumulator and brake lines in the event that the trailer vehicle breaks away from the tractor vehicle.

Claim 14

A vehicle braking system comprising a vehicle brake mechanism; hydraulic actuator means for operating said brake mechanism; a dual purpose hydraulic accumulator for storing hydraulic fluid under pressure; said hydraulic accumulator including a brake spring adapted to mechanically apply brakes of the vehicle said brake spring being compressed to relieve said brakes of said mechanical actuation when hydraulic fluid is stored in said accumulator; a hydraulic pump having a pump outlet; an unloader valve having an inlet port, a pressure port, a drain port, a valve seat between said inlet port and said drain port and a valve closure member coOperating with said valve seat and movable away from said valve seat responsively to a predetermined pressure applied to said pressure port; means connecting said pump outlet to said inlet port; means connecting said pressure port to said accumulator; means interconnecting said inlet port and said pressure port for charging said accumulator to said predetermined pressure whereupon said valve closure member opens said valve seat to connect said inlet port to said drain port to unload said pump; an emergency valve controlling a connection between said accumulator and said hydraulic actuator means; and means for actuating said emergency valve.

Claim 15

A vehicle braking system comprising a vehicle brake mechanism; hydraulic actuator means for operating said brake mechanism; a dual purpose hydraulic accumulator for storing hydraulic fluid under pressure; said hydraulic accumulator including a brake spring adapted to mechanically apply brakes of the vehicle said brake spring being compressed to relieve said brakes of said mechanical actuation when hydraulic fluid is stored in said accumulator; a hydraulic pump having a pump outlet; an unloader valve having an inlet port, a pressure port, a drain port, a valve seat between said inlet port and said drain port and a valve closure member coOperating with said valve seat and movable away from said valve seat responsively to a predetermined pressure applied to said pressure port; means connecting said pump outlet to said inlet port; means connecting said pressure port to said accumulator; means interconnecting said inlet port and said pressure port for charging said accumulator to said predetermined pressure whereupon said valve closure member opens said valve seat to connect said inlet port to said drain port to unload said pump; an emergency valve controlling a connection between said accumulator and said hydraulic actuator means; and means for actuating said emergency valve.