Note: The
fi
xing screws of the freaction sheave and the safety brake are marked by locking varnish.
Loosening of the screws is therefore visually recognisable. If a screw should turn, it must be
retightened with the prescribed torque, the old locking varnish removed and remarked.
For further information on maintenance, refer to the ZAS operating instructions.
4
Flank backlash measurement
4.1
General information
The ZAS0, ZAS1, ZAS2 and ZAS3 are elevator machines with work gears. On these gears, the
fl
ank
backlash of the gearing has to be monitored.
The
fl
ank clearance of the gearing is referred to as the rotation play of the traction sheave in the
original operating instructions.
The check is necessary as wear occurs on the tooth
fl
anks of the worm gear. The tooth width is
reduced by wear and the clearance increases. This clearance is known as
fl
ank clearance and is a
measure of the wear to the worm gear.
The
fl
ank clearance must be measured annually. There is a choice of a simpli
fi
ed or comprehensive
measurement of the
fl
ank clearance. If the maximum permitted
fl
ank clearance is reached in the
simpli
fi
ed measurement, the comprehensive measurement must then be performed.
CAUTION!
Attention!
If the
fl
ank clearance exceeds the maximum permitted value, the elevator machine may no longer be
used on safety grounds. An inadequate tooth width can lead to breakage.
4.2
Simpli
fi
ed
fl
ank clearance measurement
4.2.1
Requirements
"
Move the empty car to the top
fl
oor.
"
Check that the shaft doors and the car doors are closed.
"
Switch on the recovery control.
"
If necessary, reduce the return speed.
"
Carefully lower the counterweight onto the buffer by moving the car further upwards at the return
speed.
"
Open the mechanical brake and leave it open.
4.2.2
Procedure
"
Turn the hand wheel until you feel a resistance.
"
Select a reference point, e.g. the edge of a brake liner, and make marking 1 at this point on the
brake drum.
"
Turn the hand wheel in the opposite direction until you feel a slight resistance. Now make marking
2, also at the reference point location on the brake drum.
"
The traction sheave should not move during this process.
"
The distance S between marking 2 and marking 1 on the brake drum shows the size of the
fl
ank
clearance.
"
Repeat the process several times to make sure that the stop positions at both ends are precisely
de
fi
ned.
"
Check whether the size of the
fl
ank clearance is within the appropriate tolerance, as shown in the
following table.
Service instructions
ZAS0, ZAS1, ZAS2, ZAS3
Flank backlash measurement
A-TIA19_07-GB 1936 Index 001
Part.-No. 01013457-GB
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