MAHA MPJ Series, Original Operating Instructions

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BA550001-en
5 Safety devices
5.1 Pressure relief valve
A pressure relief valve is installed between the pump and the non-return valve.
This pressure relief valve limits the hydraulic pressure that can be generated by
the pump and thus prevents loads that are too heavy from being lifted.
The pressure relief valve is adjusted to the load capacity and set at the factory.
This setting must not be changed.
5.2 Self-closing drain valve
With the electro-hydraulic pit jack, the lowering valve is opened via the "Lower"
button. The lowering speed can be adjusted using the rotary knob.
The operating elements are self-resetting, i.e. the lowering valve closes
automatically when the button is released.
All other types are equipped with a drain spindle that opens the drain valve by
turning it counterclockwise. When the drain spindle is released, a spring closes
the valve automatically.
5.3 Overflow device for limiting the end position of the cylinders
The manual single-stage pit jack MPJ 1S and the pneumatic pit jacks are
equipped with an overflow device. When the end position of a cylinder stage is
reached, a bypass opens and prevents the cylinder stage from being extended
further and leaving the guide.
On all other pit jacks, the travel of the cylinder stages is limited by a mechanical
stop.
5.4 HAE main switch
The electro-hydraulic pit jack has a main switch. If this is turned to "0", the
power supply to the pit jack is switched off. The main switch also functions as
an emergency stop.