Tips for conveyor maintenance- belt splicing

-- Modern Materials Handling, 8/1/2003

When improper tension and alignment lead to torn, overly stretched or sagging belts, the belt may need to be spliced rather than replaced. Splicing a belt reconnects two belt ends by means of a highly intensive heat or chemical process or with mechanical hooks. Either splicing technique involves precision and should be performed by knowledgeable maintenance personnel.

Essentially gluing the belt ends, vulcanization uses either a heat or chemical activation process to transform a cut belt into an endless belt. The intensive heat method melts the belt fabric and bonds it together again. The chemical activation technique involves cutting the belt ends into a step-like pattern and rejoining them with a heat-activated or cold-setting adhesive. Vulcanization creates long-lasting splices but this method needs highly skilled personnel to install the splice. Also, it is generally more expensive than mechanical splicing and can involve lengthy downtime as the conveyor belt is repaired.

Mechanical splices, also referred to as alligator splicing, use fasteners on each belt end that mesh together and are connected with a hinge pin. Some types include wire hooks and hinged-plate fasteners, which are especially suited to light- to medium-duty applications in warehouses. Such hooks penetrate through the belt ends and lace together to create a long-lasting splice.

However, if mechanical splices are not installed correctly, more problems will develop. For instance, the hooks may disengage over time if they were not clinched well enough or if the wrong hook size was used. Also, if the hooks pull through the belt without opening or the entire splicing breaks just behind the fasteners, there are two possible causes. The belt may not have been squarely cut before being spliced, or the hooks may not have been installed far enough back on the belt to withstand tension load.