Composite sheet material

Abstract

In a method of producing composite sheet material by forming longitudinal rows of stitches 7 in a paper sheet material 1, the length of paper sheet material 1 used per stitch 7 is increased so that there is entrapped within each stitch 7 in each longitudinal row of stitches 7 a portion of paper sheet material 1 having a length greater than the length of the completed stitch 7. In consequence there are formed in the composite sheet material a longitudinal series of laterally extending corrugations, ridges or ribs which, in the case of a crepe paper sheet material 22, constitute a gross crimp imposed without distortion of the crimps in the initial crepe paper sheet material 22. The increase in the length of the sheet material used per stitch may be effected by the action of the needles 9 of the stitching machine to withdraw a greater quantity of sheet material 1 or 22 from a feed roll or the increase in the length may be effected by positively overfeeding the sheet material 1 or 22 to provide slack sheet material which is entrapped within the stitches 7 as a result of the needle action. The method of the invention may be used when producing composite sheet material by stitching through a plurality of sheets 23, 25 or 27, 28, 30 of sheet material. When there are a plurality of sheet materials the increase in length may be confined to only one or some of the sheet materials or may be provided in all the sheet materials. The paper sheet material may be either plain paper or crepe paper or when a plurality of sheet materials are used a pair of either plain or crepe or any combination thereof.

Dependencies are inferred from the claim text.