| 摘要 |
A web of material is predisposed to folding by being passed through a pair of cooperatively mounted mating rolls; i.e., a male and female roll, which roll along what become the lines of fold of the web, prior to its being manipulated into its folded position. The rolls tend to loosen bonds in the web transverse of the ultimate lines of fold, thereby facilitating folding. Because the mating rolls manipulate the web only slightly, in distinction to the action of conventional folding devices, the web maintains its alignment while passing through the mating rolls relatively well, resulting in accurately located lines along which the web is predisposed to fold. Since the lines of predisposition to folding are accurately located, the ultimate folded structure is more dimensionally consistent than heretofore possible. In the preferred embodiments, the rolls press against the web with constant pressure, rather than being fixedly mounted, thereby providing a built-in adjustment for variations in web thickness.
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