Apparatus for continuously stretching or continuously releasing stretching forces from a web using two pairs of opposing non-planar belts

摘要

In accordance with the present invention there is provided an apparatus for conveying a web. The apparatus is able to continuously stretch the web or continuously release the stretching forces from a web in the cross-machine direction. The apparatus includes two pairs of opposing belts wherein each belt travels along an endless path. The pairs of belts diverge or converge from each other in the cross-machine direction. Each pair of belts comprises an upper belt and a lower belt which are adjacent to each other. Each of the upper and lower belts has a non-planar outer surface which contacts the web. The non-planar outer surfaces of each upper belt continuously abuts the non-planar outer surface of its adjacent lower belt along a predetermined distance when traveling in the machine direction. This creates at least one nip for continuously gripping the web while it is being conveyed. The apparatus also includes a means for driving the belts so as to convey the web in the machine direction.