Abstract: An improved fluid power actuator assembly comprising a power piston reciprocatingly mounted in a cylinder bore which is formed in a compact fluid power manifold providing the necessary circuit connections between control valves mounted on the housing and the cylinder bore. The cylinder bore preferably includes two circumferentially spaced signal ports disposed in the wall of the cylinder bore along the path of travel of the piston in addition to the primary power ports located at each end of the cylinder bore to drive the piston. The piston includes at least one circumferential groove and functions as a spool valve for opening and closing communication between the signal ports as the piston travels in the cylinder. Appropriate control valves and signal pressure communicating with the signal ports is disclosed to enable a fluid power signal to be generated which is related to the position of the piston during its travel in the cylinder bore.

Abstract: An orifice shield for preventing blockage of an orifice restriction by large particulate matter relative to the size of an orifice restriction in a fluid power control circuit. The orifice sheild incorporates a unitary body provided with a wire coil wound about an external threaded portion of the body. The body includes an internal blind bore and longitudinal slots which cooperate to communicate with the opening between coils of the wire. One end of the body is provided with a rotational driver receiving recess to permit external thread on the body to be threaded into a mating bore. A conventional set screw or round head bolt may be readily modified to form the one piece body portion.

Abstract: A control logic circuitry comprising a toggle type fluid actuated pilot control valve which is activated by a fluid pressure signal pulse to shift between a first and second state to deliver a control signal to a main power control valve. The pilot control valve and associated circuitry includes the capability to maintain itself in either one of the shifted states after termination of the pressure signal pulse until actuated to the other state by another pressure signal pulse. The pilot control valve is described in connection with controlling the functions associated with a linear fluid power piston including switching a main power valve to reverse the piston stroke.

Abstract: An improved fluid power actuator assembly comprising a power piston reciprocatingly mounted in a cylinder bore which is formed in a compact fluid power manifold providing the necessary circuit connections between control valves mounted on the housing and the cylinder bore. The cylinder bore includes at least two circumferentially spaced signal ports disposed in the wall of the cylinder bore along the path of travel of the piston in addition to the primary power ports located at each end of the cylinder bore to drive the piston. The piston includes at least one circumferential groove and functions as a spool valve for opening and closing communication between the signal ports as the piston travels in the cylinder. Appropriate control valves and signal pressure communicating with the signal ports is disclosed to enable a fluid power signal to be generated which is related to the position of the piston during its travel in the cylinder bore.

Abstract: A shrunk fit annular valve sleeve assembly characterized by a land configuration which provides a reduced annular area of engagement with the surrounding housing compared to the annular area of the base portion of the land disposed inwardly toward the spool bore to reduce the effects of temperature changes which cause spool bore deflection when using different metals for the housing and the sleeve. One preferred embodiment of a valve sleeve described defines a generally truncated triangular upraised land formed by complimentary shaped adjacent recesses when the sleeve is viewed in a section taken along a radial plane perpendicular to the axis of the spool bore.

Abstract: A hydraulic sensor and pressure transducing apparatus is disclosed which is characterized by the use of a biased piston and valve element arrangement to translate the displacement of an actuator to provide a pressure signal proportional to the displacement being sensed. The piston is mounted in a bore provided with inlet and outlet ports. A valve element is positioned in the bore in an opposing resiliently biased relationship to the piston in communication between the inlet and outlet ports. A constant selected hydraulic flow is fed into the bore inlet through the valve element and out of the bore outlet port to develop a pressure on the inlet port side which is proportionally to the displacement of the piston as reflected by the biased force exerted against the valve element. An actuator is linked to the piston by a cam surface in a manner that permits the angular position of the cam operating on the piston to be reflected as a proportional pressure on the inlet side of the valve element.

Abstract: A fluid power control valve apparatus is disclosed and is characterized by combining desirable features of both a spool type valve element and a poppet type valve element. A spool element is provided with one end adapted to be seated in a poppet valve seat provided in the bore in which the spool is slideably mounted. The poppet seat is located in the bore between two flow ports. The poppet end of the spool engages and becomes fully seated only after the spool has passed a bore position closing one of the ports to operative flow and operates to seal the bore from the conventional leakage flow associated with spool elements. Also disclosed is a method of manufacturing such an apparatus in a two piece assembly to greatly simplify manufacture of a precise poppet seat within the spool bore.

Abstract: A fluid power control system is disclosed which is characterized by a construction which provides for utilization of very basic fluid power flow elements and pilot signal elements to form a vast multitude of power flow control functions using a minimum number of standardized valving elements. The control system comprises a power flow manifold which serves to interconnect a plurality of pilot actuated power valving elements of a given power flow circuit arrangement which represents a multitude of potential circuit flow paths for switching and modulating requirements. The power flow manifold is provided with a plurality of internal pilot flow passages communicating with key power flow circuit junctions and pilot ports of the power flow valving elements. The pilot flow passages are arranged such that each outlet in a given pattern in a preselected face of the power flow manifold.

Abstract: The invention contemplates a virtually hysteresis-free electromechanically actuated, valve, wherein an electrical input current is converted into a substantially rectilineal force or displacement, using a single electrical coil and two spaced and oppositely polarized air gaps. Similarly spaced, opposed parts of the coil are compliantly mounted for and constrained to move in the respective air gaps, the constraint being such as to develop substantially a unidirectional force and/or displacement which is in the plane of the gap-shrouded parts of the coil. The actuating mechanism is described in the context of an hydraulic-valve, with incorporation of a viscous-damping feature.

Abstract: The invention contemplates improved hydraulic-pressure control apparatus which will proportionally reflect input-signal changes governing a wide range of output pressures. Use of a separate preamplifier stage, between a signal-pressure stage and a power stage, enables the signal pressure to remain essentially unaffected by load reaction or other transients at the power stage. In the forms described, an input electrical signal determines a step-function program of signal-pressure levels, and the power stage includes a relief valve which so diverts system-line flow to a sump as to assure quick and accurate response of system-line pressure to the instantaneous input electrical-signal level, all without system-pressure overshoot.

Abstract: The invention contemplates a virtually hysteresis-free actuator for converting an electrical input current into a substantially rectilineal force or displacement, using a single electrical coil and two spaced and oppositely polarized air gaps. Similarly spaced, opposed parts of the coil are compliantly mounted for and constrained to move in the respective air gaps, the constraint being such as to develop substantially a unidirectional force and/or displacement which is in the plane of the gap-shrouded parts of the coil. Various embodiments of suspension and force-output pick-off and development are described.

Abstract: A fluid power control apparatus which comprises the unique combination of a control housing including a cylindrically shaped core member mounted in a sealed relationship within a receptacle member. A plurality of grooves or recesses generated in the outer wall surface of the core member define selected fluid path connections in axial and circumferential directions to radial passages formed in the core and receptacle members to communicate valve elements in the core or receptacle members to one another and to external means in almost any selected manner. This combination forms in a relatively simple and dramatically compact manner any preselected simple or complex fluid control circuit in a single package.

Abstract: A hydraulic motor control apparatus comprising a plurality of standard multiple function modules adapted to be selectively programmed in various arrays to effect substantially any required hydraulic control function.