| 摘要 |
An apparatus and method for forming one or more pleats in a continuously advancing sheet of indeterminate length are provided. The apparatus includes a first roll, over which the sheet passes while a streak of adhesive is laid upon a selected strip of the sheet, and a composite roll, to which the sheet passes as a reach under selectively varied tension. The composite roll includes a parallel roll and an inclined roll which is inclined at a pleat angle to the parallel roll and is driven by rolling contact with the parallel roll while passing through a pinch zone at the apex of the pleat angle which is 0.25 DEG to 5 DEG , preferably about 1.5 DEG . The periphery of the inclined roll may vary from a right circular cylinder to a right circular cone with its peripheral surface at a bevel angle to the circular side thereof. The bevel angle is preferably one half of the pleat angle. The pleat is formed by gathering the strip into the circularly converging gap between the inclined and parallel rolls and then lightly compressing the pleat between the sides of a circumannular recess between the rolls.
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