Production methods for fibrous and/or pliable material are known, in particular for webs of paper, fabric, hide, etc. In the case of fibrous materials the production methods generally consist of pouring a mix of fibrous material and water onto an endless conveyor belt in movement. Here the mix is progressively deprived of its water content and subjected to a series of traditional processes which finally lead to the obtaining of a paper web or, in more general terms, to the obtaining of a web of fibrous material, to be then fed to subsequent uses.
These subsequent uses can consist of printing on the paper web or its transformation by suitable successive passages, for example on paper processing machines, etc.
As the production process requires the fibrous web to undergo a lengthy path it is advantageous to utilize this path to obtain further modifications which increase the value of the fibrous web in addition for example to the removal of water. To this end, one solution consists of introducing during the path one or more modules which enable paper webs with improved physical characteristics to be produced, for example extendable in the transverse direction. They are generally combined with a method for producing paper webs also extendable in the longitudinal direction, hence enabling paper webs to be produced extendable in all directions.
One of these known methods, described in U.S. Pat. No. 2,535,734, causes a paper web to adhere to an endless elastic belt which is in the process of contracting. This method uses either open endless belts which are of considerable length or elastic tubes mounted on inclined discs fixed on a jointed movable shaft which, by rotating, enlarge or contract the elastic surface. In this latter case the space within the sleeve is inaccessible from the outside, the rotary movement being impressed by the jointed movable shaft on the discs fixed to it. The compact apparatus provided with an elastic tube described in U.S. Pat. No. 2,535,734 cannot perform operations other than transverse compression; moreover it is not specified whether it can treat the paper during the formation process in a continuous machine.