Vestil S-xxx-FF - Manual (Page 52)

52
Chain inspections
Chains used in stackers should be inspected at least once a year or every three months if
exposed to severe contamination or high continuous loading stress.
We recommend that attention be paid to the following points:
1. Unusual noise
2. Surface rust
3. Linkage rust
4. Stiff links
5. Distorted pins
6. Loose link pins
7. Damage
8. Broken link plates
9. Broken pins
10. Contamination
11. Stretching
Even with the optimum amount of lubrication, it is impossible to prevent a chain from
stretching.
Wear extends only to that part of the chain which is led over the chain
sprocket/guide sprocket. Thus, when checking for wear, only check the area need
be inspected.
According to the regulations currently in force, a chain is deemed to be worn if it has
stretched by 3%.
If safety issues are particularly critical or a potential hazard is dependent on a single chain,
we consider it necessary to replace it if it is stretched by even 2%.
Measuring procedure
To measure elongation through wear, that part of the chain which runs over the chain
sprocket/guide sprocket must be positioned in the stretched area. With the aid of a
measuring rod, measure a section approximately 1 meter in length.
The number of divisions in the measured area, multiplied by the chain divisions, gives the
nominal measurement.
The length extending beyond this measurement represents the wear, which is limited to a
maximum of 3% over the nominal length.
An elongation through wear of 3% is reached if 33 links of the chain in use measure the
same length as 34 links of a new chain.
Chain replacement
If two chains are used as a pair on the affected machine, both should always be changed
at the same time.
The installation and removal of chains should be carried out with all the care appropriate
to any item of safety equipment.
Chains may only be repaired by authorized specialist personnel.
We do not recommend the lengthening of safety-type lifting chains, since the inserted
chain link will not have been pre-stretched.
Our product liability will be invalidated if a repaired chain is assembled from sections
bearing different silver label numbers.
Maintenance and repair