Abstract:
The present invention relates to a system preventing the pressured oil leakage in a cylinder line enabling very low leakage rates without using the valve or the system, or without reducing the diametrical space between the housing and spool.
Abstract:
The present invention ensures that an element (13) that prevents falling of the load by entrapment of the hydraulic fluid within a hydraulic cylinder also functions as discharging the entrapped hydraulic fluid in order to assure the lowering operation at the same time. As the said novelty in the system shall also function as the load retainer check valve, it is possible to achieve very low leak rates without employing any lowering valve or system or without reducing the diametric gap between the spool and the body.
Abstract:
The present invention relates to an arrangement for controlling two drive units which interact with one another, one of which consists of a hydraulically driven motor (2). This forms part of a hydraulic system in which hydraulic fluid under pressure forms a main flow through a main duct (1) in which the motor is connected. The motor drives a varying load, and one or more valves (6, 7) control the hydraulic fluid flow through the motor on the one hand during operation and on the other hand for starting and stopping of the motor. One of the valves consists of a flow control valve (7) for flow control of the hydraulic fluid flow through the motor. The second drive unit (37) performs a working movement which, under the action of hydraulic flow under pressure, influences the loading of the motor. The flow of the hydraulic fluid to/from the second drive unit is controlled in a coordinated way with the control of the flow through the motor.
Abstract:
A directional control valve (4) has snap-locking means (2) for retaining the slide (6) of the directional control valve in at least one switching position. The snap-locking means have a snap-locking part (8) with a snap-locking piston that allows an engagement part (12) to engage and lock the slide of the directional control valve. Kick-out means (16) disengage the engagement part when a predetermined control pressure is exceeded. The kick-out means triggering force may be adjusted by means of setting means (22) that act on a kick-out spring (20). Switching means (24) that allow the kick-out function to be switched off independently of the setting of the setting means are associated to the directional control valve in order to prevent disengagement independently of the initial stress of the kick-out spring.
Abstract:
A hydrostatic steering device has a pump (2) connected to a tank (1), a steering valve (4) provided with a metering pump (6) and operated by a steering handwheel (7), and a steering cylinder (13). The steering has a variable working flow and a constant pilot flow. The pilot flow flows through a constant orifice (6) and the pressure drop across the constant orifice serves as a control signal for the flow rate in a pressure line (3). The metering pump is coupled mechanically with an adjustable orifice (15) through which the pilot flow passes. A pressure compensator (16) located between the constant orifice (6) and the adjustable orifice (15) is controlled by the differential pressure of the adjustable orifice. The load signal passes through a control line (18) which branches off between the constant orifice (6) and the pressure compensator (16) and travels to the pump (2) or, in a constant pump connected to a flow-dividing valve (21), to the flow-dividing valve.