A valve assembly is provided. The valve assembly includes a valve body defining a bore. The valve assembly further includes a pull rod disposed in the bore and defining a bolt cavity. The pull rod is moveable between a first pull rod position and a second pull rod position. The valve assembly further includes a bolt disposed in the bolt cavity and moveable with respect to the pull rod between a first bolt position and a second bolt position. The valve assembly further includes a spool disposed in the bore. The spool is operatively coupled to the pull rod to move between an energized position and a neutral position.

Brake fluid reservoir valve for installation in the reservoir's outlet tube. It includes an outer sleeve fixed in the reservoir tube and equipped with an outer stop and a hollow piston housed in the sleeve. The top of the piston is closed and bordered by a groove accommodating an o-ring seal that rests upon the upper edge of the sleeve whenever the piston enters the sleeve. The piston has windows beneath the groove communicating with the interior of the piston and lugs near its lower extremity. Openings are provided in the extension of the piston beneath the lugs. A compression spring is inserted between the piston and the outer sleeve, between the stop and the lugs.

Brake fluid reservoir valve for installation in the reservoir's outlet tube. It includes an outer sleeve fixed in the reservoir tube and equipped with an outer stop and a hollow piston housed in the sleeve. The top of the piston is closed and bordered by a groove accommodating an o-ring seal that rests upon the upper edge of the sleeve whenever the piston enters the sleeve. The piston has windows beneath the groove communicating with the interior of the piston and lugs near its lower extremity. Openings are provided in the extension of the piston beneath the lugs. A compression spring is inserted between the piston and the outer sleeve, between the stop and the lugs.

An electrohydraulic transmission control system having a parking lock valve by which a parking lock cylinder of a parking lock device can be charged with an actuation pressure adjustable in an operating-state-dependent manner by at least one pilot pressure adjustable in the region of an electrohydraulic pressure adjuster and/or one pressure source. Above a defined actuation pressure level, the parking lock valve can be held in a defined operating state in which the actuation pressure can be applied to the parking lock cylinder. The actuation and pilot pressures can be applied to a valve device such that when the actuation and pilot pressure levels approximately correspond to one another, the region of the control system which conducts the actuation pressure is operatively connected, upstream of the parking lock valve, to a pressure region in the region of the valve device with a pressure lower than the defined actuation pressure level.

An electrohydraulic transmission control system having a parking lock valve by which a parking lock cylinder of a parking lock device can be charged with an actuation pressure adjustable in an operating-state-dependent manner by at least one pilot pressure adjustable in the region of an electrohydraulic pressure adjuster and/or one pressure source. Above a defined actuation pressure level, the parking lock valve can be held in a defined operating state in which the actuation pressure can be applied to the parking lock cylinder. The actuation and pilot pressures can be applied to a valve device such that when the actuation and pilot pressure levels approximately correspond to one another, the region of the control system which conducts the actuation pressure is operatively connected, upstream of the parking lock valve, to a pressure region in the region of the valve device with a pressure lower than the defined actuation pressure level.

The application discloses a method for controlling a pneumatic brake system of a vehicle. The method includes the step of modulating a pilot-control brake pressure by means of an electropneumatic pilot-control valve in venting phases and bleeding phases. The method also includes the step of feeding in the pilot-control pressure via a pilot-control line for outputting a brake pressure to wheel brakes of the vehicle.

The application discloses a method for controlling a pneumatic brake system of a vehicle. The method includes the step of modulating a pilot-control brake pressure by means of an electropneumatic pilot-control valve in venting phases and bleeding phases. The method also includes the step of feeding in the pilot-control pressure via a pilot-control line for outputting a brake pressure to wheel brakes of the vehicle.

A system for controlling a brake of a unit hauled by a work vehicle may generally include a valve assembly. When a speed of the work vehicle exceeds a predetermined speed threshold, the valve assembly may be configured to allow the brake to be actuated when first and second brake pedals of the work vehicle are depressed, either individually or simultaneously. However, when the speed of the work vehicle is less than the predetermined speed threshold, the valve assembly may only be configured to allow the brake to be actuated when both of the first and second brake pedals are depressed simultaneously.

A system for controlling a brake of a unit hauled by a work vehicle may generally include a valve assembly. When a speed of the work vehicle exceeds a predetermined speed threshold, the valve assembly may be configured to allow the brake to be actuated when first and second brake pedals of the work vehicle are depressed, either individually or simultaneously. However, when the speed of the work vehicle is less than the predetermined speed threshold, the valve assembly may only be configured to allow the brake to be actuated when both of the first and second brake pedals are depressed simultaneously.

A work vehicle according to the present invention includes an engine installed in a traveling machine body supported by traveling units, and a transmission case incorporating a hydraulic continuously variable transmission. The transmission case incorporates a forward/backward traveling switching mechanism. The work vehicle includes forward traveling valves for forward traveling hydraulic clutches, a backward traveling valve for a backward traveling hydraulic clutch, and a master valve configured to control hydraulic oil supplying to the forward traveling valves and the backward traveling valve. A part of a hydraulic circuit is formed on a front lid member of the transmission case. The forward traveling valves, the backward traveling valve, and the master valve are attached on a front surface side of the front lid member.