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Belt drive techniques
THE BELT TAKE UP AND DRIVE TENSION CONTROL MECHANISM
The eyelink belt and drive sprocket assembly is comparable to a timing belt / sprocket drive assembly, in that both have sprocket teeth that do not protrude through the belt. To ensure positive engagement of the teeth and belt, belt "back tension" at the exit side of the drive is required. The belt should be driven at the conveyor discharge end so that the belt is pulled, not pushed, along the product carrying path. To maintain back tension and to take up for belt elogation, a screw type take up, as shown, or automatic take up is required.
BELT SUPPORT AND GUIDANCE
The best support for an eyelink belt consists of longitudinal support rails or strips. If the temperature permits, these rails can be de dressed with protective wear material of plastic, Delrin, "Werkstoff S" (Greenstrip) or UHMWPE.
Depending on the load, the distance between these supports is approx. 25 to 40 cm. The ends of the supports where the belt arrives are, over a length of 5 to 10 cm, bent down a bit in such a way that the belt is gradually supported.
These support rails can also be installed in the return path of the belt. Here, only the weight of the belt needs to be supported, which means that there can be a larger distance between rails. However, the supports should be fitted on the positions of one or more rows of bar links. Another option is to fit free-turning support rollers into the return path at a distance of approx. 1.5 to 2.5 meters. It is all right if the belt slackens a bit in between the rollers.
TWENTEBELT eyelink belts are characterised by a remarkably straight run. Depending on the belt width and length, a space of 5 to 10 mm between the frame and belt will usually suffice. Nevertheless, when the frame is being constructed one should bear in mind that the belt cannot touch stands or sharp parts. These must be guarded to prevent snagging. The belt's run itself should be as simple as possible, avoiding reverse bends.
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