The present invention concerns an inflatable hose for trans¬ port of gas and fluids, including the method of producing same.

The invention also concerns the production of hoses for garden and hobby purposes, where special demands are made on the design and dimension of the hose.

Hoses of the above mentioned type must by definition have the following qualities:

They must be easy, they must fit standard hose couplings, they must resist common pressures from the public water pipes and they must be easy to put away. In connection with paint spraying, pump drive etc. the hoses must resist the most common pressures generated by hobby appliances. In other words, a hose for the above purposes must resist all pressures between 0-10 ato.

In order to meet the above mentioned demands, the hoses must have comparatively thin walls. This has the effect that an upper limit must be set as regards the external diameter of the hose.

Therefore the invention concerns the production of a special type of thin-walled hoses, where the hose thickness (1) con¬ stitutes from 1 to 10% of the external diameter (D) of the hose, when the hose is completely outstretched.

In order to facilitate the putting away of the hose, it must be designed in such a way that it is oriented longitudinally. This can be done by building a memory in the hose wall that directs the hose when it is being wound up.

Previously known hoses with extremely thin walls are fitted with an outer textile hose and an inner hose of another dense material. The inner hose can either be loose, ref. Norwegian Patent No. 132.770, or be fixed to the outer wall.

Hoses produced in the above mentioned manner are compara¬ tively expensive, as they must be joined, for instance by sewing. Besides, if they are to be fitted with a loose inner hose, this must be passed into them. Accordingly, it is im¬ possible to produce the hoses continuously if the above mentioned method is used.

It is known from US Patent No. 2.424.315 to produce thin- walled hoses.

It is described a hose and a method for producing same, where two textile layers that are coated on one side are con¬ tinuously passed together and with the coated sides against each other into the lamination unit, in such a way that the textile layers overlap only partly during the prelaminati ^' on. When the prelamination is finished, an unlaminated part con¬ sisting of one textile layer with coating will protrude on each side of the laminate. In the next stage of the process the laminate is bent 180 from one side and then 180 from the other, so that the before mentioned unlaminated protruding parts of the laminate overlap completely

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with the coated sides against each other and the selvages against the selvages in the various textile layers. In other words, two butt and butt joints are formed in the hose wall a little to the side of each other, but on the same half of the hose between the bending zones of the hose.

Finally, the unlaminated part of the hose laminate is joined in a combined press and heat process.

When put to use, it proves to be of decisive importance to the mechanical properties of the hose that the overlapping part of the textile layers in the joint zone is as big as possible. As a general rule we could say that the smaller this is, the less durable is the hose as such. This shall be explained:

If the two textile layers are placed butt and butt with the joints directly over each other, the tensile forces of the hose wall cannot exceed the the tensile stress of the coating itself. If the hose bursts, it bursts over the joint.

However, if the textile layers are made to overlap a bit, as shown in the said US-patent No. 2.424.315, the tensile stress of the hose wall will be between the measured shearing stress of the laminate and its tensile stress. As the shearing forces of the overlapping part are proportional to the laminated surface in the overlapping zone, the strength of the hose wall will increase in relation to the size of the laminated, overlapping part of the hose wall. In other words, it is possible to increase the strength of the hose wall by increasing the overlapping zone. Therefore the overlapping zone can be adjusted so that it constitutes between 0.1-50.0% of the external circumference of the hose. The US-patent shows a hose which overlaps by 17% between the joints. For obvious reasons the overlapping zone cannot constitute more than 50% of the external circumference of the hose.

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If, according to the method of producing the hose in the said US-patent No. 2.424.315, we try to increase the overlapping part so that it overlaps by 50%, we will find that the joints will remain in the middle of the bending zone of the hose. Furthermore, we will find that the two butt and butt joints in the hose wall become two joints where the selvages are not butt and butt but parallel over each other. The selvages do not meet end to end, and accordingly the hose will be weaker.

Therefore the object of the present invention has been to produce a hose with the above mentioned qualities and where at the same time the joints remain diametrically against each other each on one half of the hose between the bending zones of the hose, i.e. with an overlap of 50% between the textile layers.

According to the invention this has been achieved by not pre- laminating the textiles layers before the textile layers are passed into a folding device. The reason for this is to en¬ able the textile layers to move freely in relation to each other and thereby to slide over each other until they meet butt and butt in the folding device. Then the textile layers are flattened and passed continuously into a press and lamination unit under the influence of pressure and heat in such a way that the joints remain each on one half of the - hose between the bending zones of the hose.

When the textile layers are joined, the textile fibres are also exposed to molecular structural changes, which causes the textile molecules to orient in a new manner. Accordingly, at least two opposite presses are formed in the hose wall, and this has the effect that the hose folds up when it is not outstretched. In other words, the presses in the hose wall constitute the orienting memory of the hose in the longi¬ tudinal direction. This makes the hose easy to wind up and

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The threads of the textile ribbon can either be twisted or not. Usually twisted threads are used. The thread weight will normally be between 20-150 deniers.

The textile ribbons can be coated on one or both sides. Usually a coating for the said purpose will be on the basis of polyurethan, but polyvinylacetate, polyvinylchloride or another thermoplastic or thermosetting material can also be used for the purpose. The reason for this is that the coating must be diffusionproof and be adhesive when it is heated.

Fig. 2 shows the production of ribbons of the same type as those described according to Fig. 1.

The ribbons that are coated on one side (1* and 1") are passed together into a guide unit (6), where the textile layers are folded one on top of the other.

At the end of the guide unit (6) the folded ribbons are flattened in a heated press section (7), whereby the ribbons are laminated (glued together).

In the following the actual method of producing the preferred design. Fig. 1, will be described:

Two textile ribbons (1 ^* and 1") of 6-polyamid and coated on one side (2) with polyurethan are passed continuously together into a guide unit (6). See section A-A, Fig. 2.

The feeding of the ribbons is done in a known manner by pulling the ribbons through the folding device. The ribbon that is to form the inner layer (1') is folded from the top in such a way that it is shaped like a reversed U, thus 0 . See section B-B, Fig. 2. Then the outer ribbon (1") is folded around this from below, so that this also is shaped like an

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furthermore, it prevents it from twisting when it is wound on to the reel.

It should be emphasized that in the present invention it is distinguished between the terms folding and bending, as bending means bending an even surface so that a sharp angle is formed in the bending zone, whereas folding means folding an even surface in such a way that it assumes the shape of for instance a cylinder.

The invention is as stated in the claims.

For further explanation of the reel reference is made to Fig. 1, that shows a preferred design of this when two textile ribbons that are coated on one side are used, and where the ribbons are folded around each other and where the overlap constitutes 50% of the circumf rence of the hose.

In Fig. 1 the textile ribbons that are coated on one side are indicated by ( 1 * and 1") and the coating by (2). The butt and butt joints are indicated by (3' and 3") and the hose press, in the bending zone of the hose by (4).

Usually the textile is of a non-rotting material like poly- amide and polyester, or a fungicide or germicide is added, ffoorr iinnssttaannccee SSaanniittiizzeedd ^^—— iiff tt.he material is of cotton. linen or other natural fibres.

In order to prevent the hose from stretching, at least some of the threads of -the textile must be oriented in the longi¬ tudinal direction of the hose. This is achieved by weaving the threads 90 in relation to each other, i.e. 50% of the threads are placed lengthwise and 50% are placed 90 cross¬ wise in the longitudinal direction of the hose.

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open U , thus U . During the last mentioned folding of the

_e outer ribbon (1") the inner ribbon (1 ^* ) is closed in a butt and butt joint (3 ¹ ). See section C-C,-Fig. 2.

Then the outer layer (1") if folded over the inner layer (1 ¹ ), whereafter the folding of the outer ribbon (1") is finished in a butt and butt joint (3"). See section D-D, Fig. 2.

When the ribbons have been folded and are shaped like a non- glued or laminated tube, they are finally passed into a heated press device (7), so that the butt and butt joints (3 ¹ and 3") remain halfway between the folds of the hose (4), as shown in Fig. 1 and also shown by means of Section E-E, Fig. 2.

During the lamination of the textile layers two opposite presses (4) are formed in the bending zones of the hose wall. These constitute the orienting memory of the hose.

The actual lamination can be done by means of heated press elements, by means of supersonic technique, by means of high-frequency technique or by means of another device that is suitable for the lamination. Fig. 2 shows a press device (7) where the folded ribbons (1 ^* and 1") are squeezed between two parallel metal press ribbons. These can be heated in a known manner.

Hoses that are produced according to the above description have, when being tried out, proved to be very well suited for the purpose. Another feature of such hoses is that they are easily mended when they have been perforated. The repairs are done most easily by ironing the hose with a hot iron, whereby the perforation is made impervious.

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