Lukas Hydraulic cylinder - Manual (Page 9)

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4. Equipment designation
Coupling connection thread:
M = metric thread
Z = inch thread
LFO 55 / 200 Z
HLMD 55 - 25 / 200 M
Cylinder range Cylinder type Stroke Connection
thread for
couplings
single-acting
cylinders:
double-acting
cylinders:
5. Functions and performance
5.1 Description
LUKAS hydraulic cylinders can be either single or double acting. This can be seen in the
designation of the cylinder.
The movement of the piston when extending is carried out hydraulically for both cylinder
types. When retracting, only the double acting cylinders move under hydraulic force. On
single acting cylinders it takes place mechanically, e.g. by a release spring. Single acting
cylinders can also be equipped without release springs, and the retraction is actuated by the
lifted load which acts on the piston of the cylinder when the pressure is removed.
The direction of movement is controlled by the application of pressure to the rod side of
the piston (only on double acting cylinders) or to the cylinder base side. The control of
the pressurisation must be effected by an external control unit (e.g. a control valve) and
a hydraulic aggregate connected to it. The use of a hand pump instead of the hydraulic
aggregate is also possible.
In general, all LUKAS double acting cylinders are equipped with an integrated safety valve on
the piston rod side. These safety valves protect the cylinder from damage caused by pressure
transmission. If the specified maximum pressure is exceed, the safety valves automatically
open and hydraulic oil (shielded) is ejected into the open air.
WARNING / CAUTION!
Please take care that single acting cylinders can move unexpectedly if the
pressure is removed and the line to the cylinder is not closed off!