AC MUM0096 rev. 07 - 30 -
MR21
18.4. COMPULSORY MAINTENANCE OPERATIONS
It is necessary to plan the below listed checks according to the minimum schedule indicated in the
table. In any case is responsibility of the elevator maintenance manager evaluate the necessity to
increase the frequency of check in case of intense duty.
Check Frequency
Oil level 4 months
Adjustment of opening of brake shoes and fricon material thickness check * *
Wear and tear of pulley grooves 2 months
(Acousc) of condion of bearings 6 months
(Acousc) of presence of abnormal noise levels 6 months
(acousc) of presence of abnormal noise levels 6 months
Gear backlash 12 months
* The nominal thickness in 6 mm, brake shoes must be replaced before the minimum thickness of the
fricon material seaches 2 mm.
18.5. CHECKING THE GEAR BACKLASH
Due to the working principle of the worm gearbox the worm wheel is consumed by wear during the
lifeme of the gearbox. To ensure the safe funconality of the installaon it is necessary to check the
backlash regularly to make sure the backlash does not exceed the acceptable limits. There are two
ways to check the backlash between worm and worm wheel, on the input sha (worm sha) by use of
the ywheel or on the output sha (worm wheel) by use of the tracon sheave. The measurement on
the input sha is easier somemes but the check on the output sha is more reliable, for this reason
in case the backlash has been veried out of limit on the input sha we recommend to double check it
on the output sha.