8.6.3 Hold and drift function
Interval
Weekly
Aids, tools, materials
■
Tool to adjust the restraint system
■
Distance measuring systems (e.g. caliper gage, etc.)
■
Tool to remove any component covering
To check the holding function, the locking unit must be loaded with at least 25% of the permissi-
ble static holding force in the restraint system’s opening direction for at least 5 minutes.
■
The higher the force and the longer the test lasts, the more resilient the result will be. HAWE
specification: 1.5 mm / 30 min.
■
If during the check the lock position on the cylinder changes by more than 1.5 mm in the
locking direction, or if oil leaks out, the locking unit is faulty, and must be replaced.
1. Always check only one locking unit at a time (alternating checks).
Shut off all other locking units and any mechanical back-up systems and secure them all against
inadvertent restarting.
Make sure that no external force is acting on the locking unit. Otherwise the counter-pressure
might prevent the check valve from opening.
Close the restraint system as per the switching logic (page
2. Adjust the restraint system using the adjuster tool.
Make sure that at the start of the load test the permissible play of the restraint system and any
elastic factors (such as bar and seat padding) are compensated for, so as not to corrupt the
measurement.
3. Load the locking unit with at least 25% of the permissible
static holding force
according to the
technical data sheet for a minimum of 5 minutes.
4. Pay attention to the position of the piston rod before and after applying the load.
Remove any component coverings that obstruct checking.
Take into account any permissible play in the restraint system mechanism.
If during the check the lock position on the cylinder changes by more than 1.5 mm in the locking
direction, or if oil leaks out, the locking unit is faulty.
If component coverings cannot be removed, determine the transmission ratio of the piston rod
movement as a check indicator. To do this, calculate by how many millimeters the restraint system
can be adjusted with 1 mm extension/retraction of the piston rod, Take into account the seat
kinematics and bar ratio.
5. Replace the locking unit if it is faulty.
HAWE Hydraulik SE
B 6052-21 -
11
-2021 - 1.7
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