The invention relates to an electrohydraulic monitoring device for a dual
effect hydraulic cylinder in which certain operating pressures must be
maintained. A pressure reduction valve is provided for setting said
pressures, this pressure reduction valve being used to set a defined
pressure (41) by adjusting the pretension of the valve spring (41). The
valve spring is situated in a spring chamber (137) which is bordered by a
regulating sleeve (46) on one side, in an axially moveable manner. Said
regulating sleeve is displaceable between two end positions within a
limited axial stroke area. The alternative switching positions of a
micro-switch (117) are linked to these end positions. Two sensor chambers,
each of which is connected to one of the pressure chambers of the cylinder
in such a way that they communicate, are provided and are delimited by
sensor pistons (106, 107) in order to determine the operating pressure
that is being coupled into the hydraulic cylinder at a particular time.
The alternative subjection to pressure and relief from said pressure of
these sensor chambers forces the regulating sleeve into the same end
position, respectively.
