GB2217269A

GB2217269A - Making inflatable torus-shaped articles

Info

Publication number: GB2217269A
Application number: GB8903416A
Authority: GB
Inventors: Gilles Calandra; Gilles Debray
Original assignee: Aerazur SAS
Current assignee: Safran Aerosystems SAS
Priority date: 1988-02-22
Filing date: 1989-02-15
Publication date: 1989-10-25
Anticipated expiration: 2009-02-15
Also published as: FR2627516A1; GB8903416D0; GB2217269B; FR2627516B1

Abstract

A method is provided for obtaining coated fabric articles assuming, under the effect of an inflation pressure, the shape of a torus or torus section, and articles obtained by implementing this method. According to the invention, elementary strips (2, 2', 2'') having the shape of a parallelogram are cut out on the bias from a piece of fabric, then these strips are jointed end to end so as to form an assembly (4) in the form of a belt. Then the longitudinal edges (13, 14) of belt (4) are joined together by means of joining strips so as to define a closed volume which, under the effect of an inflation pressure, will assume a circular shape. The method makes it possible to obtain inflatable objects of toric or semi toric shape such as rafts, small boats, shelters, pneumatic buoys. <IMAGE>

Description

A METHOD OF OBTAINING ARTICLES MADE FROM COATED FABRICS ASSUMING, UNDER THE EFFECT OF AN INFLATION PRESSURE, A TORUS OR TORUS SECTION SHAPE AND ARTICLES THUS OBTAINED.

The invention relates to a method for forming inflatable objects and, more particularly, a method for forming objects made from coated fabrics designed so as to assume, under the effect of the inflation pressure, a torus or torus section shape.

At the present time, in the field of inflatable objects such for example as rafts, small boats, shelters, pneumatic buoys, etc..., in order to obtain a volume of circular section and of a general open or else closed shape, such as a torus or an arch in particular, it is necessary to join together, using different methods (bonding, welding, etc..) parts of predetermined developable shape as a function of the product to be obtained after inflation. When it is desired for example to obtain a torus by this method, it is in fact necessary to form a regular polygon shape approximating as well as possible the toric shape.

The cost price of such a method is all the higher the closer it is desired to approximate the shape of a perfect torus, for it is then necessary to subdivide the latter into a large number of elementary sections, which has of course a direct influence on the construction time because of the increase of assembly operations.

The elementary sections are cut out along the warp or the weft, the evolute of the small diameter of the torus being generally taken in the direction of the width, on the fabric. The form of the parts thus cut out, with more or less distorted contours, leads to a loss of fabric during cutting, although attempts are made to minimize this loss by the choice of the best available arrangement of the cutting templates during marker.

Another known method consists in cutting out the parts according to general curved shapes, no longer preferentially widthways of the fabric and along the warp or the weft but by taking advantage of its length. These parts are then assembled together, superimposed two by two and joined together side by side so as to form a torus after inflation.

Although, in this other method, the number of elementary parts is generally less than in the first above described method, the loss of fabric following maW is however similar.

The object of the present invention is to overcome the drawbacks of known methods for obtaining inflatable articles in the form of a torus and for this it provides a method which, while being of great simplicity to put into practice, is particularly economic in that it substantially reduces the losses of fabric when cutting out as well as the cutting out time.

According to the invention, the method consists in cutting out, on the bias or on the cross of the fabric, elementary parts in the form of a parallelogram which follow each other without gaps in the tabling then, after cutting out, joining these elementary parts edge to edge or by overlapping them by means of an assembly strip cut out along the warp or the weft, until a closed belt is formed and finally joining together the two edges of said belt, edge to edge or by overlapping, by means of a fabric strip cut out along the warp or the weft and fixed to one of the faces of the fabric.

If required, the other face of the fabric may receive a second reinforcement or sealing strip.

After introduction of the inflation pressure inside the volume thus defined, the assembly takes on a toric shape.

It will be understood that cutting out the elementary parts in the form of a parallelogram, without gaps between them, on the bias of the fabric, leads to a saving while substantially reducing the cutting time as well as the fabric losses during cutting. It will also be noted that the assembly of the elementary parts together is facilitated, since it takes places on the flat along a straight line, and that the time required for carrying it out is therefore reduced. The method thus facilitates the use of assembly machines and so the automation thereof.

It will be readily understood that if, according to the invention, it is desired to obtain an object in the form of a torus portion, an arch for example, the elementary parts and the assembly thereof together takes place in the same way as mentioned above for constructing a torus, except that the assembly of the joined together parts will not be closed on itself. Once the longitudinal edges of this strip have been joined together, each end of the strip is then closed by joining together the transverse edges thereof, for example along a straight line.

For a better understanding of the method of the invention, a preferred embodiment thereof will be described hereafter, by way of example, without any limitative character, with reference to the accompanying schematic drawings in which Figure 1 is a top view of a portion of a coated fabric strip from which the elementary parts are cut out Figure 2 is a perspective view showing the closed strip formed by joining together the elementary cut out parts; Figure 3 is a vertical sectional view of the object obtained by joining together the edges of the strip of figure 2; Figure 4 is a view corresponding to figure 3 showing the toric shape assumed by the object after inflation of the inner volume of the strip; and Figure 5 is a perspective view of an object in the form of a torus portion formed in accordance with the invention.

Referring to figure 1, a piece of coated fabric 1 has been shown from which elementary strips 2, 2', 2" have been systematically cut out on the bias, between the two edges of the fabric, which strips each have the form of a parallelogram and which follow each other over the marker without any gap.

The elementary strips 2, 2', 2"...thus cut out are joined together edge to edge (by bonding or any other appropriate method) using a joining strip 3 cut along the bias, then the assembly of strips thus joined together (see figure 2) is closed in the form of a belt 4 by joining together the two ends of the elementary strips edge to edge.

The two edges 13, 14 of the belt 4 thus formed are then joined together edge to edge, as shown in figure 3, by means of a fabric strip 5 cut out along the warp or the weft and fixed by bonding (or any other appropriate method) to the external face of belt 4.

A strip 12 of coated fabric (but which could be formed by a plastic film not reinforced with fabric) is, if required, fixed opposite strip 5 on the inner face of belt 4.

Introduction of the inflation pressure, by means of valves 6, inside the volume 7 defined by joining together the edges of belt 4, gives to the whole the desired toric shape, shown in figure 4.

In a variant, an arch has been shown in figure 5 in the form of a torus section obtained in accordance with the method of the invention. In this case, the assembly is still formed by joining together the elementary strips 2, 2', 2"...but this assembly 8 is not closed on itself.

After joining together the opposite longitudinal edges of this assembly, by means of a joining strip 9 cut along the warp or the weft, the ends 10, 11 of assembly 8 are each closed, for example along a straight line, so as to obtain a torus portion after inflation of the defined volume.

It will be understood that the above description is given by way of simple example, without any limitative character and that modifications or constructional additions may be made thereto without departing from the scope of the invention defined by the following claims.

Claims

1. Method of obtaining fabric articles assuming, under the effect of an inflation pressure, the shape of a torus or torus portion, consisting in forming an assembly (4-8) cut out along the bias of the fabric, closing said assembly (4, 8) at its ends and associating together in the longitudinal direction said assembly (4, 8) cut along the bias and a strip (5) cut along the warp or the weft of the fabric so as to form a tube, characterized in that assembly of the bias cut fabric (4, 8) is obtained by cutting out from the fabric (1) elementary strips (2, 2', 2") oriented along the bias of the fabric and having the form of a parallelogram , then joining said elementary strips (2, 2', 2") together and in that the longitudinal edges of the assembly (4, 8) cut along the bias are assembled together edge to edge or by overlapping them by means of strip (5) cut out along the warp or the weft.

2. Method according to claim 1, for obtaining a torus shaped article, characterized in that the assembly formed by the joined together elementary strips (2, 2', 2") is closed on itself so as to form a closed belt (4).

3. Method according to claim 1, for obtaining an article in the form of a torus portion, characterized in that each end (10, 11) of the assembly (8) formed by joining together the elementary strips (2, 2', 2") is closed by joining its edges together.

4. Method according to any one of the preceding claims, characterized in that said elementary strips (2, 2', 2") are cut out from the fabric (1) without gaps therebetween.

5. Method according to any one of the preceding claims, characterized in that the elementary strips (2, 2', 2") are joined edge to edge or by overlapping, by means of a joining strip cut out along the warp or the weft.

6. Method according to any one of the preceding claims, characterized in that the joined together longitudinal edges (13, 14) of the assembly (4, 8) are doubled with a fabric strip cut out along the warp or the weft or on the bias or else by a plastic film (12) fixed opposite the external joining strip (5) on the internal face of the assembly.

7. Article obtained by implementing the method according to any one of claims 1 to 6, characterized in that it is formed of an assembly (4, 8) made of elementary strips (2, 2', 2") cut out along the bias from a piece of fabric (1) and joined end to end, said assembly (4, 8) being closed on itself or not and having its longitudinal edges (13, 14) joined together edge to edge or by overlapping, by means of a fabric strip (5) cut out along the warp or the weft.