Abstract: A jack of the type having inner and outer legs and a screw for extending and retracting the inner leg relative to the outer leg. The screw is mounted on a base fixed to the outer leg for rotating and limited endwise movement between the upper and lower positions relative to the base such that the screw and inner leg can move downwardly to the lower position when the inner leg is out of ground engagement and the inner leg moves the screw toward the upper position when the leg engages the ground. A rotary drive member is mounted for rotation relative to the base about the axis of the screw and a transmission mechanism responsive to rotation of the drive member drives the screw at a high speed ratio when the screw is in the lower position and at a low speed ratio when the screw is in the upper position.

Abstract: The legs of the landing gear of a semi-trailer may be automatically extended and retracted by a pneumatically operated actuator adapted to be connected to the crankshaft of the landing gear and adapted to rotate the cross-shaft of the landing gear selectively in either direction at a high or low speed. The crankshaft is rotated by gears and ratchets which are driven by pawls adapted to be reciprocated by an air-actuated cylinder and adapted to be alternately positioned in active and inactive positions. The flow of pressurized air to the cylinder is controlled by a cycle valve and an on-off valve, the latter being capable of turning off the actuator automatically when the legs are fully retracted.

Abstract: A pivoted linkage is associated with an anti-sway mechanism in such a manner as to enable the mechanism to retard lateral sway of a trailer while preventing the mechanism from restricting forward surging of the trailer. As a result of the linkage, the anti-sway mechanism does not interfere with the operation of a surge brake actuator having pivotally interconnected front and rear units.

Abstract: A trailer is adapted to be hitched to a towing vehicle by a surge brake actuator which includes pivotally interconnected forward and rear units. When the rear unit moves forwardly relative to the forward unit, a plunger assembly is moved to a braking position to actuate a master cylinder and apply the trailer brakes. The disclosure pertains to (1) the construction and operation of the plunger assembly (2) the construction and mounting of the master cylinder (3) a friction lock for holding a breakaway cable in an emergency position when the trailer breaks away from the towing vehicle and (4) a clamping and latching mechanism for releasably coupling the forward unit of the actuator to a hitch ball on the towing vehicle.

Abstract: A trailer is adapted to be hitched to a towing vehicle by a surge brake actuator which includes pivotally interconnected forward and rear units. When the rear unit moves forwardly relative to the forward unit, a plunger assembly is moved to a braking position to actuate a master cylinder and apply the trailer brakes. The disclosure pertains to (1) the construction and operation of the plunger assembly (2) the construction and mounting of the master cylinder (3) a friction lock for holding a breakaway cable in an emergency position when the trailer breaks away from the towing vehicle and (4) a clamping and latching mechanism for releasably coupling the forward unit of the actuator to a hitch ball on the towing vehicle.

Abstract: A multi-axle vehicle brake system includes an air receiving portion, a valve portion, an air storage portion and a brake portion. The air receiving portion receives air from a supply source. The valve portion is connected to the air receiving portion. The storage portion includes a plurality of storage reservoirs connected for receiving air from and communicating air to the valve portion. The brake portion includes service and parking brake actuating chambers mounted on each end of each axle. Certain ones of the service brake actuating chambers are connected for receiving air from one of the storage reservoirs. Others of the service brake actuating chambers are connected for receiving air from another of the storage reservoirs. Each of the parking brake actuating chambers are connected for receiving air from either of the storage reservoirs.

Abstract: A multi-axle vehicle brake system includes an air receiving portion, a valve portion, an air storage portion and a brake portion. The air receiving portion receives air from a supply source. The valve portion is connected to the air receiving portion. The storage portion includes a plurality of storage reservoirs connected for receiving air from and communicating air to the valve portion. The brake portion includes service and parking brake actuating chambers mounted on each end of each axle. Certain ones of the service brake actuating chambers are connected for receiving air from one of the storage reservoirs. Others of the service brake actuating chambers are connected for receiving air from another of the storage reservoirs. Each of the parking brake actuating chambers are connected for receiving air from either of the storage reservoirs.