Method of producing reinforced, formed fabrics

This application is a division of U.S. appln. Ser. No. 10/521,160, which is the national stage of PCT/CH2003/000415, filed Jun. 25, 2003, which claims priority to CH 1150/02, filed on Jul. 2, 2002, all of which are herein incorporated by reference in their entirety.

The present invention relates to a method of manufacturing shaped and reinforced fabrics, and more particularly to a method of manufacturing shaped and reinforced fabrics continuously in alternation, the fabric being constituted by composite elements which are constituted by a membrane, impervious for example, which encases reinforcing elements, threads for example, the elements constituting the fabric being capable of being shaped in three dimensions so that the fabric has a desired shape in three dimensions.

Reinforced and shaped fabrics are used in all cases where a fabric has to be reinforced generally and in particular when a fabric has to be reinforced in particular directions which are determined by the forces that act on the fabric. By way of example, when a fabric acted on greatly by forces comprises fixing eyelets at the location of its corners or elsewhere, reinforcements may be necessary to distribute the forces, maintain the shape and avoid tears. Moreover, if large forces act between one or other of the eyelets, reinforcements may be necessary in the direction of the forces.

In many cases, it is necessary for the fabric to have particular shapes in three dimensions whether for reasons of performance or for aesthetic reasons.

The manufacture of high-performance reinforced and shaped fabrics is subject to several parameters including of course commercial criteria which require that a fabric must be high-performance, as light as possible and of course with a price as low as possible.

Many embodiments of reinforced and shaped fabrics and of reinforced and shaped fabric manufacture are known but they all have many drawbacks.

A basic drawback of all the known high-performance reinforced and shaped fabrics is that the structure of the fabric is constituted by an assembly of elements of the sandwich type, that is to say the fabric consists of at least three components, these being the reinforcing elements which are assembled by bonding in a sandwich between two polymerised plastic sheets, for example. This type of fabric construction is expensive and has a fairly heavy weight. The polymerised plastic sheets are semi-rigid and may not allow local deformations. The overall shape of the fabric must allow a desired shape to be obtained over the whole dimension of the fabric which consequently requires moulds with the total size of the sail which are very expensive. These manufacturing methods with total-size moulds have several drawbacks, one of the greatest of which is the cost which is inevitably carried over to the end product. Another drawback is the space requirement of these moulds which require very large production premises. Moreover, the large cost of the tools implies a lack of flexibility when changes in shape are necessary which slows down the development phases and makes them very expensive. As the reinforcing threads are generally each placed in one piece with these embodiments, the positioning is very tricky.

Other known embodiments are implemented by assembling several fabric panels from different cuts, the panels being assembled together by sewing or bonding. The location of the sewing is fragile and requires reinforcing panels themselves added on by sewing. The forces to which the fabric is subjected are therefore dependent on the strength of the sewing at these locations which, as said, has the drawback of requiring reinforcing panels which contribute towards increasing the overall weight of the fabric. Moreover, at the locations of the sewing and the reinforcing panels, the fabric is less flexible than the other panels of the fabric, which causes many creases and fatigue of the materials when the fabric takes the desired shape, which is unsightly and can reduce the performance of the fabric for certain forms of use.

The aims of the present invention therefore consist of remedying the aforementioned drawbacks of the known embodiments.

The aims are achieved according to the principles of the invention as described in claim 1.

The method of manufacturing shaped and reinforced fabrics according to the principles of the invention consists of carrying out the manufacture of the fabric continuously. A press of small width compared with the length of the fabric successively presses the constituent elements of the fabric. Reinforcing elements, threads for example, are prepared on a belt which is disposed able to move on a preparation table and discontinuous reinforcing elements are disposed overlapping the waiting part of the fabric already pressed. The reinforcing elements can thus be disposed in all directions according to the direction and magnitude of the forces to which the fabric is subjected. The upper and lower chambers of the press comprise movable and adjustable devices which make it possible to obtain, during pressing, a desired shape in three dimensions at desired locations. By successive forward movements of the fabric and depending on the adjustments, the fabric can have flat portions or have portions in three dimensions, and the shape of the portions in three dimensions can be varied quickly according to the final shape provided for the fabric. The elements that constitute the fabric consist of threads which are encased by a membrane which is constituted by resin. Before pressing, these elements are in the form of strips which can be constituted by a prepreg of resin and threads, the preimpregnation having the advantage of holding the threads. Once pressed, the fabric is constituted by the membrane which is the resin which encases the threads or rather the filaments of the threads. In fact the threads are constituted by thousands of filaments which are distributed over the width of each strip. During preparation, part of each strip is placed on the juxtaposed strips and during pressing the filaments of the different strips intermix so as to constitute a homogeneous and impervious fabric for example.

The principles of the invention have many advantages. One of the major advantages is that the fabric once completed is constituted, in section, by two elements, these being the membrane and the reinforcing filaments, and consequently the manufacturing method allows the elements to be reduced in comparison with the known three-layer embodiments. This reduction in the number of elements makes it possible to obtain a reduction in the weight and cost.

The fact that the completed fabric is in the form of a membrane encasing thousands of intermixed filaments makes it possible to obtain a highly homogeneous sail, with no creases and with reinforcements which make it possible to withstand all the forces to which the fabric can be subjected. The membrane and the filaments also have the advantage of being practically indeformable in the direction of the forces whilst being highly flexible during folding of the fabric for example.

The press has a very small space requirement compared with the dimensions of fabrics to be manufactured which makes it possible to install it in premises of small dimensions.

The shaping device integrated with the press which makes it possible to obtain portions of fabric in three dimensions, which makes it possible to obtain a finished fabric in three dimensions, has many advantages. One of these advantages is that the shaping device makes it possible to eliminate the expensive tools such as the three-dimensional moulds or tools. This is because the shaping device can allow a multitude of different shapes to be obtained by simple and very quick adjustments. This advantage is very important during manufacture but is also very important during the development of new fabrics having new shapes, the adjustment device making it possible to obtain a new shape very quickly by simple and quick adjustments.

The principles of the invention make it possible to considerably reduce the manufacturing costs whilst making it possible to obtain higher performance fabrics.

The accompanying figures illustrate schematically and by way of example the principles of the invention.