Fluid controller with integral auxiliary valving

Reference Number: N 02-03

Inventors: Stephenson, Dwight B.; Rasmussen, Kenneth G.; Schutten, H. P.

Owner: NISTAC

USPTO Link: 5129424

Invention Summary

Accordingly, it is an object of the present invention to provide an open-center system for controlling flow of pressurized fluid to both a main device and an auxiliary device, wherein only a single valve assembly is required to perform both valving actions.

It is a more specific aspect of the present invention to provide such a system in which the valving to the main device is automatically and mechanically given priority over the valving which controls flow to the auxiliary device.

The above and other objects of the present invention are accomplished by the provision of an improved controller operable to control the flow of fluid from a source of pressurized fluid to a main fluid pressure operated device, and to an auxiliary fluid pressure device. The controller is of the type including housing means defining a fluid inlet port for connection to the source of pressurized fluid, a return port for connection to the system reservoir, and first and second main fluid ports for connection to the main fluid pressure operated device. Valve means is disposed in the housing means and composes a primary, rotatable valve member and a cooperating, relatively rotatable follow-up valve member, the primary and follow-up valve members defining a neutral rotary position and a rotary operating position in which the primary valve member is rotatably displaced from the neutral rotary position, relative to the follow-up valve member. The follow-up valve member defines a neutral axial position. The primary valve member defines first and second fluid passages and the follow-up valve member defines a first fluid port in continuous fluid communication with the inlet port, and a second fluid port in continuous communication with the first main fluid port, the first and second fluid ports being blocked from fluid communication with the first and second fluid passages, respectively, when the valve members are in the neutral rotary position. The first fluid port is in fluid communication with the first fluid passage, to define a first variable flow control orifice, and the second fluid port is in fluid communication with the second fluid passage, to define a second variable flow control orifice, when the valve members are in the rotary operating position. The housing means and the valve means cooperate to define a main fluid path providing fluid communication between the first and second variable flow control orifices when the valve members are in the rotary operating position.

The improved controller is characterized by the housing means defining first and second auxiliary fluid ports for connection to the auxiliary fluid pressure operated device. The follow-up valve member defines a first axial position, and the controller includes means operable to bias the follow-up valve member toward the neutralaxial position, and means operable to displace the follow-up valve member toward the first axial position. The housing means and the valve means cooperate to define a first auxiliary fluid path providing fluid communication from the inlet port to the first auxiliary fluid port, and from the second auxiliary fluid port to the return port, when the valve members are in the first axial position.