4.3.4
Saddles for hollow plunger cylinders (models HHJ and HAHC)
Hollow plunger cylinders can be equipped with a standard hollow saddle or a threaded hollow saddle.
Both types of saddles are mounted in the plunger by a threaded connection.
To avoid the plunger from turning during mounting of the saddle. Pump out the cylinder until the piston
touches the stopring and some pressure is build up in the cylinder.
WARNING
Always make sure the saddles are fully screwed into the plunger. The threaded connection is
designed to keep the saddle in position. Not to take the full cylinder force.
Not taking this warning into account may lead to severe damage to the plunger head.
4.4
During use
4.4.1
During use
•
Prevent damage to the unit.
•
Continuously monitor the behaviour of the load.
•
Always lift and prop the load in steps. (with a lock nut cylinder, the lock nut can be used)
•
Use a tommy bar for turning the lock nut. Never place your hand between the cylinder and lock nut .
•
On cylinders without a stop ring, the red O-ring indicates the end of the stroke. Do not extend the
plunger any further.
•
On cylinders with a stop ring, the stop ring is designed to absorb the full force, but if possible do not
use the full stroke of the plunger. This will reduce plunger wear.
•
The retraction speed of the plungers inside gravity, spring and air return cylinders is slowed down
due to restrictions in the oil return path.
•
Use more cylinder capacity than the load requires:
Symmetric load: total cylinder capacity = 1.5 x load
Asymmetric load: total cylinder capacity = 2 x load
4.4.2
Lifting
•
Set the pressure relief valve on the pump to "operation". The plunger will extend.
Refer to the user manual of the pump and the control valve.
NOTICE
The speed of lifting (and lowering) can be controlled with a throttle or reducer valve.
Contact the Holmatro dealer for more information.
WARNING
Use a tommy bar for turning the lock nut. Never place your hand between the cylinder and
the lock nut.
Lock nut cylinder HJ***G ** SN / HLC***H**
•
When the required elevation is reached, screw the nut against the cylinder housing.
•
The hydraulic pressure can now be removed from the cylinder and the hose(s) can be
disconnected. The load is removed from the seals and taken up by the nut. The cylinder can
mechanically retain the load for a long period.
WARNING
Lock nut cylinder HLC***H**
The cylinder is equipped with a safety valve in end position. Do not use the maximum
stroke to prevent loss of pressure in end position. (Fig. 11 and Fig. 19)
HYDRAULIC CYLINDERS
916.000.851_007
EN
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