Mannesmann Rexroth Corporation

Bosch Rexroth Ag

Mannesmann Rexroth Ag

Wolfgang Lukasczyk

Rainer Imhof

Roland Ewald

Rainer Drechsler

Karl Rub

Norberto Thiesing

In a pressure switch, which emits an electrical switching signal as a function of the magnitude of a pressure which is supplied to it, which electrical switching signal assumes a first value when the pressure is less than the threshold value and which assumes a second value when the value is greater than the threshold value, the threshold value is adjusted&#x2014;assuming that this is provided at all&#x2014;by hand, for example by moving a cam disk which is coupled to a rotary knob. In order to adjust the threshold value by an electrical signal, the pressure is supplied to a pressure sensor, which emits an electrical output signal, which is a measure of the pressure which is supplied to the pressure sensor. The pressure switch is supplied with an electrical input signal which is a measure of the threshold value. The electrical output signal from the pressure sensor and the electrical input signal are supplied to a logic circuit, which emits an electrical switching signal which assumes one of two values as a function of the magnitude of the difference between the electrical signals which are supplied to it. The pressure switch is used generally for signaling on reaching a pressure which can be preselected. The pressure switch is used in particular in automation devices.

Pressure switch with electrical correction signal for adjusting threshold values

Metal valve housing

A pressure relief valve system is provided that makes it possible to provide numerous varied pressure relief functions with a minimum of structural changes. For this purpose, a standard distributing valve housing is equipped with a valve core that makes it possible to construct a double-acting pressure relief valve with an individually adjustable pressure system on each valve side. However, there is also the possibility of completely shutting off the pressure system on one side. The valve core and/or the valve elements are preferably exchangeable, and the valve elements can be separately controlled by an adjusting device, for example in the form of a proportional magnet, to generate a pressure output signal corresponding to an input signal in each of the independent pressure systems independent of one another.

Adjustable pressure relief valve

A two-way control valve includes a valve member with a longitudinal bore connecting its opposite ends with each other. A housing receives the movable valve member and has two attachment ports. A control piston is operatively coupled with the valve member. To provide a two-way valve permitting pressure medium to flow in both directions when the valve member is moved from its closed position, the control piston is tightly or fixedly connected with the valve member and is arranged as an annular collar on the periphery of the valve member. The longitudinal bore is free of constrictions.

Multi-way valve

A pressure control valve construction comprising a valve body having an inlet port adapted for connection to a pressure source, a pair of working ports adapted for connection to respective loads, and a pair of outlet ports connected to a reservoir. A control spool is movably mounted in a bore in the body and includes lands for respectively controlling communication between the inlet port and respective ones of the working ports and between the working ports and the outlet ports. The control spool has opposite ends with blind bores respectively provided therein, and sensing spools are respectively mounted for sliding movement in the blind bores to define spaces between the bottoms of the blind bores and the sensing spools. The spaces communicate with the working port via respective openings in the control spool. In the case of a double acting valve, an actuator is provided at each end for acting on a respective sensing spool whereas for a single acting control valve only one actuator is provided.

Pressure control valve

An adjustable resistance circuitry is connected in parallel to the coil of a solenoid to adjust the actuating force of a magnetic drive means for valves.

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Lohr/Main, Germany

Wolfgang Lukasczyk