Abstract: A telescoping assembly includes an inner tubular member and an outer tubular member, each defining an internal passage. The inner and outer tubular members are mounted to each other for telescoping movement therebetween, and a pair of coaxial springs are mounted within the internal passages defined by the inner and outer tubular members. The springs act to bias the tubular members toward a retracted position. The tubular members are movable to an extended position against the force of the springs, by introduction of pressurized fluid into the internal passages defined by the inner and outer tubular members. A valve is mounted to an end of one of the tubular members, for introducing pressurized fluid into the internal passages defined by the tubular members, and for allowing fluid to be expelled therefrom under the force of the springs, for allowing the inner and outer tubular members to move to their retracted position.

Abstract: A system for leveling a vehicle, such as a recreational vehicle, includes three extendable and retractable fluid-operated jacks. The jacks are spring-biased to their retracted position. Supply of hydraulic fluid under pressure extends the jacks, and the jacks are retracted by relieving the supply of hydraulic fluid pressure to the jacks to allow the springs to expel fluid from the jacks. A number of unique aspects are incorporated in the leveling system for providing highly advantageous construction, operation and installation.

Abstract: A lifting and lowering system for a trailer includes one or more extendible and retractable legs, with the legs being provided with springs or the like urging the legs toward their retracted position. The system is a pressurized air/hydraulic system, and includes an air-operated booster valve for extending the legs when loaded. A master valve assembly is provided for controlling supply of air to the system and for allowing retraction of the legs. The master valve and air valve include a common actuator shaft so that the system is selectively connected to pressurized air or vented, as appropriate, when leg extension or retraction occurs. The master valve includes a cam actuator/cam follower piston operated system for selectively providing fluid pressure to a lock valve associated with each leg. The lock valve is biased toward a normally closed position, and is selectively movable to an open position for allowing extension or retraction of the legs.

Abstract: A valve for regulating the bidirectional flow of hydraulic fluid in an hydraulic fluid line, wherein the flow resistance in one direction can be increased, includes a hollow body (10) with an internal seat (20), a spool member (22) slidably mounted within the body (10), the spool (22) having a cylinder portion (24) and a nozzle portion (26) containing orifices (30, 32, 34), bias means (40), and limit means (42). The spool (22) is slidable within the body (10) between a position in which fluid flows through all orifices (30, 32, 34) to provide unrestricted fluid flow when fluid flows through the valve in one direction, and a position in which the nozzle (26) engages the seat (20) to block fluid flow through some of the orifices (30, 32, 34) and thereby increase flow resistance when fluid flows through the valve in the opposite direction.