Bosch VLE 21 Series Repair Instructions page 30

en 30 | VLE 21xx | Anti-raise safety device
2. Anti-raise safety device
Contents Mode of operation of anti-raise safety device
Applicability VLE 2130, VLE 2130 F, VLE 2130 E,
VLE 2130 EL, VLE 2140 EL
Both lifting columns of the lifting platform are fitted
with a safety device to shut down the lifting platform if
the loadbearing nut is defective. Refer to Fig. 1 for the
mode of operation of the anti-raise safety device.
Fig. 1: Loadbearing nut OK
1 Guide roller
2 Loadbearing nut
3 Spindle guide
4 Lifting carriage
5 Stopper
6 Raising bracket
7 Safety nut
Fig. 1 shows the arrangement of the loadbearing nut
(Pos. 2) and the safety nut (Pos. 7) with the raising
bracket (Pos. 6) positioned between the two nuts.
These loadbearing elements are in a protected location
inside the lifting carriage and are not accessible from
outside.
During operation of the lifting platform, the safety
nut is not subjected to any load and there is a safety
clearance from the lifting carriage.
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If the thread of the loadbearing nut becomes worn,
the lifting carriage drops onto the previously non-
loadbearing live safety nut and at the same time
presses the free arm of the anti-raise safety device
into a position close to the back wall of the column
(see Fig. 2).
Fig. 2: Loadbearing nut defective
With such defective loadbearing elements it is only
possible to lower the lifting platform. On attempting
to raise the platform again, the free arm of the raising
bracket (Fig. 1, Pos. 6) becomes jammed under the
stopper (Fig. 1, Pos. 5) welded to the back wall of the
column, thus preventing upward motion.
This anti-raise safety device is never to be deactivated.
The loadbearing elements are defective if the lifting unit
locks in position roughly 10 cm above the column base
plate on moving upwards.
!
If the anti-raise safety device has been tripped,
the lifting platform is not to be used again until it
has been repaired by specialist personnel. People
standing beneath the lifting platform will be at risk if
repair work is not performed in an expert manner.
Robert Bosch GmbH