Service and Maintenance Procedures (BEL 252)

The BEL 252 has a Uni-Drive conveyor system in which both side belts are driven by a single motor and gear reducer. The Uni-Drive ensures that both belts are synchronized at the same speed, in order to keep cases square through the taping section of the machine.

The side belts are tensioned and the tracking is controlled by top and bottom adjustments on both idle pulleys. The tension of the belts should be just enough to prevent belt slippage or so that approximately one inch (2.54 cm) of play is available when the belt is pulled sideways by hand in the center of the machine. Too much tension will cause excessive strain and premature wear of the belts and pulley bearings. With the conveyor running, tighten the upper and lower bolts to position the belt so that it is running true and not trying to ride up or down on the idler pulley.

The Uni-Drive side-belt conveyor is designed to keep the case square during sealing, which results in a technically stronger seal and a better-finished appearance. This is achieved by linking the drives of both conveyor belts to a single motor and gear-reducer that inherently synchronizes belt speeds better than other belt drive systems on the market. Uniform chain tension is maintained automatically during case width adjustments through a self-compensating serpentine configuration. Chain tension is preset at the factory but if the drive becomes noisy or needs adjustment then adjust as shown below. Proper tension is achieved when the horizontal sag in the chain measures between 1/8 inch and 1/4 inch (3.1 and 6.4 mm) with drive belts in a fully opened position.

1. At the conveyor drive motor corner of the machine, loosen the idle sprocket mounting bolt enough to allow it move in its slot.

2. Unfasten the flexible plastic bellows on top of the stainless steel safety cover and remove the cover.

3. Loosen the locknut and adjust the tension chain tensioning bolt.

4. Re-tighten the idle sprocket mounting bolt.

WARNING: The drive covers must be replaced before operating the machine.

The optional BEL 252 Spare Parts Maintenance Kit contains all of the parts necessary for maintaining the Uni-Drive conveyor. See the Technical Reference manual for details, and contact the factory or your local Wexxar/BEL distributor for the kit’s price and availability.

To replace the conveyor side belts, use the following procedure:

1. Loosen the top and bottom belt tensioning bolts so that the belt is completely slack.

2. Remove the screws from the top plate and the top belt tensioning bolt from the idle pulley shaft. Lift off the top plate.

3. Remove the stainless steel conveyor cover and then remove and replace the belt.

4. Reassembly is the reverse of disassembly. Re-tension and adjust the tracking of the belts as described above. Replace the top adjustment plate. Replace all conveyor covers.

The machine arch cross-member supports the upper tape head holder on the BEL 252. It mounts to the arch assembly with vertical slide bar bearings that ride inside the arch columns, allowing the cross member to move smoothly up and down for case height adjustment.

The bearings are made of a special hardwearing plastic material but may need periodic adjustment to compensate for wear or for loosening due to frequent adjustment or operating vibration. If worn or loose, the bearings allow excessive movement of the upper tape head holder and may affect taping performance.

There are wedge-shaped spacers between the bearing bars at the top and bottom with a threaded rod adjustment between them. Tightening the nuts on the rod will reduce the bearing clearance.