Abstract: Example pilot-control stage for a proportionally controlled high-pressure hydraulic valves are disclosed.

Abstract: Example pilot-control stage for a proportionally controlled high-pressure hydraulic valves are disclosed.

Abstract: A central block is disclosed for a pilot controlled valve system with seat and piston valves. The central block has a preferably standardized connection interface (12), a pilot valve interface (13) for receiving a pilot valve (32), a pump conduit (P), a tank conduit (T), a first work conduit (A), a second work conduit (B), a first control conduit x and a second control conduit y, as well as four valve reception cavities (34, 36) for receiving each one valve unit (C.sub.1, C.sub.2, C.sub.3, C.sub.4). In order to create a central block which may be universally used with any number of hydraulic circuits and whose connections may be easily modified, the central block is composed of a middle block (2) to which are detachably secured two valve blocks (50, 60, 70, 80, 90, 100, 110, 120). The middle block (2) has two valve sides (6, 10) provided each with a valve block interface (22, 24) which receive each one valve block (50, 60, 70, 80, 90, 100, 110, 120).

Abstract: A position controlled proportional directional control valve has a main control piston for controlling flow between passages to a pump, a tank, and to passages which may be connected to an operative device, such as a hydraulic motor. The main control piston may be moved in one direction by an operating piston slidably disposed in a centring flange which serves as a mechanical stop for movement of the main control piston in the opposite direction. Acting on the end of the main control piston opposite the operating piston is a centring piston having one end in a pilot control chamber, and which may urge the main control piston against the centring flange either by pressure fluid in the chamber, or upon failure of pressure, by the spring in the chamber. A pilot control valve, under the control of an electrical magnet, moves proportionally to the current in the electrical magnet, to admit fluid under pressure from a pump passage into the pilot control chamber.

Abstract: A proportional valve comprises two electrically actuated proportional throttle valves, each having an outlet connected to a non-return valve, to each of which a seat valve is connected, each seat valve being pilot-controlled by one of the proportional throttle valves; the electric actuation of the proportional throttle valves proportionally controls and regulates the functions of a hydraulic cylinder. The two throttle valves and the two seat valves are mounted on a housing block which has a planar face at which are connections to a pressure line, a tank line and working lines.

Abstract: The throttle-part of the valve comprises a two-way seat valve with a follow-up throttle valve (8), which is driven by a differential guide piston (12) and an edge control system (20). The guide piston is pressurized via a pressure-spring (16) in a pressure-spring compartment in the direction of the closed position of the edge control system. The drive is effected via a pilot line A which pressurizes or depressurizes the pressure-spring compartment (18) via a proportional directional control valve (6), while the position of the guide piston (12) is determined by an inductive displacement transducer.

Abstract: The main control piston (8) is controlled hydraulically by pilot control slide valves, operated in each case via two control magnets (4, 6) with force build-up proportional to the control current. In the case of failure of the electrical activation, the valve is always positioned in the center position by pressure centering and in the case of failure of the pilot control pressure it is positioned in the center position by spring centering.

Abstract: A two-way flow regulating valve with a hydraulic compensator (120) axially movable inside a cylindrical casing is intended to regulate the flow between an inlet opening an one or a plurality of discharge openings (10) radially arranged in the casing wall. A regulation valve (18) controls the position of the compensator, a flow rate sensor (20) detects the through flow rate and a displacement detector (32) detects the position of the flow sensor and controls the regulation valve (18) in relation to the position of the flow sensor. A compact construction is obtained by configuring the flow sensor (20) as a piston which is axially movable and coaxially arranged within the compensator (12).

Abstract: The control block consists of four seat valves arranged in pairs above one another and opposite one another in two planes parallel to the base surface of the control block, the valves located diagonally opposite one another being controllable in pairs via a pilot valve. The logical combination of the invididual elements makes it possible to construct a compact, space-saving and handy control unit with a sealing surface arranged according to the customary standard pattern.

Abstract: An adjustable throttle valve is controlled by a low pressure control pressure acting on a spring urged adjusting cylinder for positioning the end of a follow-up piston adjacent the end of a discharge channel extending the length of a throttle piston; power fluid flows from a source through a discharge opening between a housing and the throttle piston with the spring force, the control pressure, infeed pressure and discharge pressure acting in concert to maintain the end of the follow-up piston adjacent but slightly spaced from the end of the discharge channel for maintaining throttle piston equilibrium.

Abstract: A hydraulic flow control valve is disclosed which is adapted for use as a pressure reducing valve, a flow control valve, or as a pressure relief valve. The valve includes a choke piston slidably mounted in a cylindrical bore for movement between a closed position closing communication between inlet and outlet channels, and an open position permitting such communication. An adjustable control system is provided for biasing the piston toward one of either its closed or open positions, and includes a constant volume flow restriction valve for providing a constant volume hydraulic flow. Downstream of the constant volume flow valve, there is provided a first branch line leading to an adjustable transducer for maintaining a selected pressure in the line, and a second parallel branch line leading to the bore in the housing for biasing the piston. Thus a selected pressure may be maintained in the second line, and thus also upon the piston, by adjustment of the transducer.

Abstract: A hydraulic flow control valve is disclosed which is adapted for use as a pressure reducing valve, a flow control valve, or as a pressure relief valve. The valve includes a choke piston slidably mounted in a cylindrical bore for movement between a closed position closing communication between inlet and outlet channels, and an open position permitting such communication. An adjustable control system is provided for biasing the piston toward one of either its closed or open positions, and includes a constant volume flow restriction valve for providing a constant volume hydraulic flow. Downstream of the constant volume flow valve, there is provided a first branch line leading to an adjustable transducer for maintaining a selected pressure in the line, and a second parallel branch line leading to the bore in the housing for biasing the piston. Thus a selected pressure may be maintained in the second line, and thus also upon the piston, by adjustment of the transducer.