초록 ▼

An improved hydraulic circuit for automatically sequencing a pair of hydraulic cylinders through alternate extension and retraction cycles. A manually operated control valve initiates addition and withdrawal of fluid within the circuit and a logic valve determines which cylinder will be in communica

An improved hydraulic circuit for automatically sequencing a pair of hydraulic cylinders through alternate extension and retraction cycles. A manually operated control valve initiates addition and withdrawal of fluid within the circuit and a logic valve determines which cylinder will be in communication with the control valve. The circuit uses an improved flow restrictor arrangement for creating the pressure drop which automatically shifts the logic valve. The restrictor consists of an orifice, a simple check valve and a constant pressure relief valve, all arranged in parallel. The functions of these various restrictor elements can all be performed by a single multifunction valve disclosed herein.

대표청구항 ▼

A multifunction valve comprising: a valve body having first and second intersecting bores, said first bore being closed at one end, said second bore being a stepped bore closed at the end of the large diameter section, the step portion providing a valve seat about the periphery of the small diameter

A multifunction valve comprising: a valve body having first and second intersecting bores, said first bore being closed at one end, said second bore being a stepped bore closed at the end of the large diameter section, the step portion providing a valve seat about the periphery of the small diameter section; a valve spool slidably disposed within and engaging the walls of said large diameter bore section, having a valve face for sealingly contacting said valve seat; means for biasing said spool toward said valve seat; a flow limiting orifice passage communicating said first bore with the large diameter section of said second bore; a check valve passage communicating both sections of said stepped bore on opposite sides of said spool, said check valve passage having a check element for blocking fluid flow from said small section to said large section.