| 摘要 |
An improved stretcher/expander roller is disclosed. The roller includes a rigid core which is rotatably mounted downstream from where a traveling web is slit. An elastomeric covering around the core has at least one pair of helical lands formed in it which each spiral outwardly away from the center of the roller. The lands are inclined outwardly away from the center of the roller and progressively increase in flexibility from the center to the ends of the roller. The roller imparts axial forces on the web strips to simultaneously separate the web strips from one another and cross-stretch each web strip. The lands are made progressively more flexible by either progressively increasing the depth of the helical grooves between the lands, by progressively decreasing the helix angle of the lands, or by progressively decreasing the angle subtended by each land and the axis of the roller, from the center to the ends of the roller.
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