| 摘要 |
Plastic web advancing apparatus for thermoforming equipment wherein the plastic web is indexed by being pulled between a three-roller arrangement located on the downstream side of a forming press. The rollers are driven by a stepping motor for intermittent indexing of the web through the press. Upstream of the forming press, the web is threadedly received between a pair of relatively movable clamping rollers which upon cyclical opening of the forming press are used to tension and feed the web in conjunction with the three-roller arrangement on the downstream end of the press. Upon closing of the press, the upstream clamping rollers are moved away from each other to release the web, enabling the web to shift and diagonally position its edges in alignment with the forming dies in the press.
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