Superabrasive
User Manual
Original Language
Lavina® 25E
2/2019
25
8.8 TENSIONING AND REPLACING THE BELTS
The
transmission of the machine runs two timing belts (a main belt that
rotates the plates (and tools) and an auxiliary planetary belt which propels
the rotation of the head as a whole). To change the main belt, remove all
plate holders and adapters. There will be a seal to remove as well. Check
any friction surfaces for wear, and replace if necessary. To remove the
bottom cover, unscrew the bolts at the circumference of the cover, as well
as those in the spacers. We recommend that all seals (O‐Rings in the
pacers and seal around the cover) be replaced when changing belts.
Figure 8.8.4 shows the scheme of the belts. To remove the old bels first
remove the planetary belt (1) and then the main belt (6).
To remove the main belt (6), loosen nuts (4) and (5) enough to be able
to turn the tensioners (3) around the central axle. Clean the washers and
surrounding area, and check all bearings of pulley units/tensioners for too
much clearance or rolling noise. Rotating the tensioner will allow the
centre distance to be reduced in such that the timing belt may be fitted
without force. Installation with the use of force is NOT permissible at any
time as this can damage the high quality, low stretch tension cord and
other components. This damage is often not visible. Arrange the belts in
pos.6 as per the scheme, paying attention to their orientation at every
pulley. Loosen the nuts (5) to the end of the bolt, and fully loosen the nuts
on the half moon (4), allowing the rotation of the tensioners with minimal force.
Using nuts (5), tighten the belt, double checking the position/orientation of the belt and the
gearing in each pulley.
Rotate the gear while tensioning to allow regular distribution of tension along the belt.
Measure the tension using a Frequency Tension Tester (Optibelt 3 TT) (Fig. 8.8.3). Tension in
span “А” of the belt should be 120‐130Hz. It is possible to use the pre‐installed support (Fig.
8.8.4‐2)(Fig. 8.8.5) as a reference to stop the tensioner at the desired belt tension, provided
that the supports have not been moved from their factory position.
ATTENTION:NEVER “OVER” TENSION THE BELT, THE BELT WILL BE DESTROYED AND IT WILL NEVER RECOVER ITS ORIGINAL
TENSION
To remove the planetary belt (Fig.8.8.4‐1), unscrew the screw of the front washer (Fig.8.8.6) and the two screws of the conical sleeve
(Fig.8.8.7). Screw one of the removed screws into the free thread(Fig.8.8.8) to push the washer down (Fig.8.8.9); take off the conical
sleeve and the belt (Fig.8.8.10).
Figure 8.8.3
Figure 8.8.1
Figure 8.8.2
Figure 9.7.4
Figure 8.8.4
