A serious problem for vehicles provided with tyred wheels is that of deflation due to perforation, which not only causes the inconvenience and expense of having to change the wheel, but also and above all creates a situation of considerable danger.

Numerous solutions have been proposed in the prior art: a first group comprises systems with a plurality of inner tubes; these solutions are fairly complex since all the inner tubes have to be isolated from each other and therefore have to be inflated separately, and they also result in a considerable increase in the weight of the wheel.

A second group comprises systems using an internal tyre lining with a layer of self-sealing product, which according to the various cases can consist of: semifluid substance or mixtures of liquids with powders, possibly contained inside containment layers, low hardness elastomers, elastomers with closed cells filled with pressurised gas, etc.; again, these solutions not only result in increased weight, but can also cause hazardous conditions of unbalance, and furthermore they do not always provide effective, lasting results. A third group consists of self-supporting tyres which permit travel at low speed for a limited distance even when deflated: this is therefore a passive system which does not prevent deflation but does reduce its negative consequences.

One aim of the present invention is to provide a flexible fluid sealing means which is capable of maintaining a seal even in the presence of perforations or small cuts.

A further aim is to provide a tyred wheel for vehicles which does not deflate even subsequent to perforation, without sacrificing simplicity of construction, reliability and low weight.

In a first aspect of the present invention, there is provided container means capable of containing a loose product and comprising a body of elastomeric material provided with a sealing surface defined by one face of said body, characterised in that said body is in a state of elastic compression in a plane containing said sealing surface, said state of compression being such as to prevent the leakage of said product through an interruption in the physical continuity of said material.

Advantageously, in each portion of said container means containing said sealing surface, said state of elastic compression acts along each and every direction passing through said portion and parallel to said sealing surface.

Within the context of this description, the expression loose product is taken to mean a fluid product such as a liquid or gas, flowable products such as powders and granules, or mixtures of said flowable products with liquids or gases.

In a second aspect of the present invention, there is provided containment means capable of containing a pressurised fluid and including a sealing surface which acts against a covering means external to said containment means when said fluid is at its working pressure, characterised in that said sealing surface is provided with ripples when said fluid is at a pressure substantially lower than said working pressure in such a way that said containment means is subjected to compressive stress parallel to said sealing surface when said fluid is at said working pressure.

In a third aspect of the present invention, there is provided inner tube means for tyres, characterised in that it has an external surface provided with corrugations or ripples.

It is advantageously envisaged that said elastomeric body be in a state of elastic extension along an orthogonal direction to said sealing surface.

In an advantageous embodiment, said body of elastomeric material is associated with a further body capable of maintaining said state of compression.

In a further embodiment, said body of elastomeric material is anchored to and/or resting on said further body.

Said body and further body may be integrated.

Said body and further body may also consist of the same elastomeric material.

In a further advantageous embodiment, said body of elastomeric material may contain said further body inside it.

In a fourth aspect of the present invention, ther is provided a method for making a containment means that comprises joining a body of elastomeric material to a further body in a connecting surface, either or both the said body and said further body being subjected to elastic stress at least parallel to said connecting surface.

Said body and said further body may be joined by gluing.

Said stress may occur prior or subsequent to said joining.

In one embodiment, said stress is a compression to which said body is subjected prior to said gluing.

In a further embodiment, said stress is a tension to which said further body is subjected prior to said gluing.

In practice, said body can have elastically reduced dimensions along a direction parallel to said connecting surface.

It is envisaged that said further body can have larger dimensions along a direction parallel to said connecting surface than the dimensions assumed by said further body after said gluing. Said enlarged dimensions may be obtained by elastic elongation.

It is also envisaged that said body of elastomeric material be provided with a surface intended to rest on said further body and shaped in a rippled manner.

A method is envisaged wherein the rippled thickness of said body is reduced while its material thickness is increased.

A method is also envisaged for obtaining said elastic reduction in rippled thickness and/or said elastic increase in the material thickness of said body due to pressure exerted by the contained fluid.

It should be emphasised that while this means is particularly suitable for the containment of gases or liquids under pressure, it is also suitable for the containment of solid materials such as powders.

It should be emphasised that the invention can be applied to numerous other technical fields, such as: balls of all sizes and in particular for sports use, such as tennis, football, rugby, volleyball, etc., inflatable waterborne or airborne means, life belts, pipes, footwear, gloves and waterproof clothing; it can also be pre-packed in sheets, rolls or other forms for appropriate use.

The advantages and characteristics of the invention will be clear from the following detailed description, which refers to some forms of implementation illustrated in the Figures in the four attached drawings.

Figure 1 is a cross-sectional view of the containment means in accordance with the invention.

Figure 2 is a view as Figure 1, referring to a preceding manufacturing stage, of a first part of said containment means.

Figure 3 is a view as Figure 1, referring to a preceding manufacturing stage, of a second part of said containment means.

Figure 4 is a view as Figure 1, showing an operational stage of perforation.

Figure 5 is a view as Figure 4, showing behaviour in a subsequent operational stage.

Figure 6 is a partial cross-section of a tyred vehicle wheel, with the containment means applied according to the invention.

Figure 7 is a partial cross-section of a tyred vehicle wheel, with the containment means applied according to a further embodiment of the invention.

Figure 8 is a partial cross-section of a detail of Figure 7, in a preceding stage.

Figure 9 is a partial cross-section of a further embodiment of the containment means according to the invention.

Figure 10 is a partial cross-section of another further embodiment of the containment means according to the invention.

Figure 11 is a partial cross-section of a vehicle tyre with the containment means of Figure 9 applied.

Figure 12 is a partial cross-section of a vehicle tyre in a variant of the invention, prior to inflation.

Figure 13 is a cross-sectional view like that of Figure 12, in another variant.

Figure 14 is a partial and interrupted perspective view of an internal part of the tyre shown in Figure 12.

Figure 15 is a cross-sectional view like that of Figure 13 after inflation.

As shown in Figure 1, the containment means 1 consists of a first elastomeric body 2 and a second body 3 anchored to it ; said body 3 can advantageously contain a fibrous structure 4 capable of improving the characteristics of non-extensibility.

In its free unstressed state, the elastomeric body 2 has a length A and thickness B, whereas after being anchored to body 3 it has length C and thickness D, A being greater than C and D being greater than B; the body 2 is therefore in a state of elastic extension along the direction M and elastic compression along direction E.

As shown in Figures 4 and 5, the penetration of a blunt instrument through said containment means 1 causes a perforation or laceration 6, although after extraction of said blunt instrument 5, the surface layer 7 of said elastomeric body 2, due to forces acting in directions E, will tend to reclose said perforation or laceration 6, hence preventing any leakage of gas.

It should be emphasised that said seal is guaranteed, within certain limits, regardless of the pressure of the gas contained: an increase in the pressure F also gives rise to a proportional increase in the force acting in the direction E in addition to the elastic forces of the elastomeric body 2; this is due to the fact that an elastomeric body with a low modulus of elasticity behaves as if it were a fluid, so the forces applied to it are transmitted in all directions.

Figure 6 shows the application of the invention to a tyred vehicle wheel; a tyre 8 of the so-called tubeless type mounted on a normal rim 9 is provided internally with an elastomeric layer 2 precompressed along directions parallel to the sealing surface 7 and anchored to the external body of the tyre 3 at least at the peripheral areas 10.

Figure 7 shows a possible application of the invention for a wheel provided with inner tube 11: in this case the elastomeric body 2 consists of the same inner tube 11, which during operation will have thickness G, whereas in a free condition outside the tyre the same inner tube has thickness H, where H is less than G; this is made possible by using an inner tube whose cross-sectional and diametric extensions are considerably larger than the internal dimensions of the tyre.

Figure 9 shows a different configuration of the containment means 12 in which the elastomeric body 2 is anchored in a precompressed manner to body 3a on both faces; the advantage of this configuration lies in the fact that in this case the forces in play are balanced, so such an article can be produced in sheets, rolls or other forms as a semi-finished product for subsequent usage; this can facilitate or obviate the need for precompression operations during the stage of anchoring or resting on body 3. An application of this type is illustrated in Figure 11, which shows an enlarged detail of a tubeless tyre 8, bearing tread marks 13 on its external part and a containment means 12 resting against its inner surface 14, to which it is firmly anchored with an airtight seal, at least in the proximity of the end zone 10. Obviously the containment means 12 may in this case consist of a continuous strip cut to a suitable length or of a strip closed in a ring.

Figure 10 shows a configuration like that of Figure 9, where however the layer 3a is replaced by a reticular layer, possibly of fibrous fabric 3b, incorporated in the elastomer 2.

Furthermore layer 3 and 3a may form a single body with layer 2 without discontinuities as it can consist of the same material.

Figures 12,13,14 and 15 show a containment means according to the current invention applied to a vehicle tyre in which the body of elastomeric material 2 has a rippled surface with an undulating shape defined by a plurality of surfaces of adjacent and radiused spherical segments 15, in Figure 13 with convexity oriented towards the surface of the tyre casing making up the body 3, and in the variant in Figure 12 with the convexity oriented in the opposite direction. More in general, said body 2 has a substantially constant thickness Q and is shaped in such a way as to form depressions alternating with and adjacent to protuberances. Said protuberances and depressions are advantageously connected by inclined and radiused surfaces without undercuts. This makes it possible to join the body 2 to the further body 3 without performing precompression on body 2; this precompression is obtained automatically during inflation when, due to pressure, the rippled surface is flattened against the inner surface of the tyre casing 3 and consequently the overall thickness P of body 2 is reduced and its material thickness is increased from the value Q to the value N. A first advantage of this embodiment is that it can easily be applied to any normal tyre casing, even one already in use on a vehicle, by inserting inside it an inner tube with a rippled surface according to the invention. Preferably this inner tube should have a volume, when filled without undergoing extensional stress, equal to the internal volume of the tyre casing; this way it will be possible to obtain the maximum value of precompression while maintaining ease of insertion and without giving rise to problems of overlapping of folds. A second advantage is that the elastomer is subjected to stress only after inflation, hence reducing problems of ageing in the warehouse. A third advantage is that an inner tube of this type can easily be produced, without significantly higher costs, using the manufacturing techniques used for normal inner tubes, simply by modifying the shape of the pressing-vulcanising mould.

This system with rippled body 2 can also be applied to tubeless tyres: in this case said rippled body 2 is firmly anchored with an airtight seal at least in the proximity of the peripheral zones 10 and vent holes 16 may be provided to avoid the accumulation of air. On the other hand it may be envisaged that accumulated air is maintained between bodies 2 and 3 in isolated bubbles, body 2 remaining totally or partially corrugated: in this case such air will be evacuated solely in the event of perforation and only from tubeless in the proximity of the perforation itself; therefore to promote an airtight seal of said bubbles, it may be envisaged that sealing or gluing substances be used in the contact zones between bodies 2 and 3.

Naturally this rippled surface may be designed with any shape, overall thickness or size, bearing in mind that the use of a greater thickness Q will permit a self-sealing function even in the event of larger perforations, lacerations or cuts.

A further method for the construction of containment means 1, 12 is also envisaged, comprising joining said elastomeric body 2 to a further body 3 and subsequently making said body 2 react with substances capable of causing it to increase in volume.

Said substances may consist of solvents such as benzene, methylethylketone, toluene-ethanol azeotrope, etc.

It should be emphasised that the construction of a tyre in accordance with the current invention does not preclude the concurrent adoption of other conventional active or passive safety systems in order to obtain maximum reliability.