The invention relates to a flexible, soft, axially collapsible and stretchable tubing consisting of a full length element with corrugations (K) internally and externally along the tubing, which at specific deformations, such as bending or compression of the tubing, are compressed and cause a constant aperture to be upheld in the cross-section of the tubing.

A flexible tubing of said kind is known from a number of products, for example GB 709,055A, being easily foldable longitudinally, and a bendable tubing system comprising a flexible, tubular wall formed from at least two soft layers of, for example, rubber, and a reinforcing strand of hard material, for example metal. The reinforcing strand constitutes the supporting structure and forms an axial helix, disposed and fixated between the layers, such that the soft layers constitute a continuous expanse between the coils of the helix. In folded or bent state, this type of flexible tubing exhibits an axial section with corrugations internally and externally along the tubing, controlled by the supporting structure. In unfolded state, it will have a relatively smooth surface, broken only by minor corrugations at the helical strand. The construction of flexible tubings with hard elements in the supporting structure restricts the flexibility to force impacts in the form of bendings and axial foldings. In case of other types of force impacts, there might be a risk that either the hard element in the construction gets deformed or material fractures occur, such that the tubing is unable to reassume its original shape upon end of impact. Furthermore, the hard element of the supporting structure will restrict the elasticity and softness of the flexible tubing, and hence also limit its possibilities of use.

A flexible tubing of said kind is also known from US 2,011,277,865A1, said tubing consisting of an element of one elastic material, for example rubber, with internally as well as externally corrugated walls in both relaxed and impacted state. The tubing construction with elastic material and helical corrugations along the tubing, said corrugations controlling the movements of the walls at specific deformations, makes possible axial compression of the tubing and also makes it resistant to fracturing. The flexible tubing construction in one elastic material necessitates a comparatively thick structure relatively to its diameter in the aperture in order to avoid collapse in the aperture at bending. The sturdy structure imparts a certain rigidity to the material, causing the flexibility and softness of the tubing at bending or other types of impacts to be restricted. It is the object of the invention to create a flexible, elastic, soft, sound-absorbing tubing suited for, but not limited to, air systems in the fields of ventilation, air conditioning, and suction. Especially well-suited for ventilation and suction in such situations where the tubing is hanging freely and visibly and where extra flexibility is needed such as, for example, for mobile ventilation or suction fittings. Here, there are stringent

requirements as to the flexibility and elasticity of the tubing, since it must be possible to move it around and for it to be freely movable, for example when adjusting height adjustable tables. Also, there may be a risk of it getting exposed to inexpedient force impacts, and hence it is important for the tubing to be capable of subsequently reassuming its original shape, almost irrespective of the type of force impact. This may be necessary if, for example, the flexible tubing is disposed on the floor where it risks getting trod on. In order to make the tubing compatible with the ventilation trade and other applications with high-quality requirements it is important that inexpedient evaporations be avoided from materials to the air being conveyed. Hence, it is also an object to create a flexible tubing without evaporations from, for example, plasticizers. Said object is achieved by constructing the flexible tubing with a soft structure of textile (T). The textile is processed and shaped to form a tubing with internal and external corrugations (K) along the tubing in relaxed as well as impacted state, creating controlled bending, stretching (U) and compression (Z) of the tubing. By folding the textile such as to obtain corrugations (K) along the tubing, the rigidity of the textile is strengthened, thereby enabling it to function as supporting structure in the tubing walls.

In order to create optimal air-flow, air density, strengthen the tubing structure, and encapsulate loose fibers, the textile is treated with an elastic material such as, for example, latex (L) or silicone. In order to retain high flexibility, elasticity, and softness it is important that the correct relation exists between the thickness of the soft textile (T) and the stiffer material, such as latex (L) or silicone. Optimally, the structure per se with the textile (T) is sturdier than the elastic treatment (L), since for example latex gets stiffer with thicker layers.

By constructing a flexible tubing with a soft supporting structure (T) and a strengthening, elastic treatment (L), a tubing is obtained having great flexibility both at bending, stretching and compressing. Also, the tubing can stand deformation without occurrence of fractures, and in most cases by far it will reassume its original shape upon end of impact.

The construction offers the possibility of forming tubing for the ventilation trade exclusively from natural materials, such as wool (T) and latex (L), both beinglOO % biodegradable and without harmful evaporations. The uneven surface of the wool textile will create a natural sound-absorbing effect, which is advantageous for ventilation products.

The tubing folding may be shaped to form a helix (S) and will exhibit, in axial section, two sides with convex (E) and concave (A) arches disposed mutually off-set, as set forth in claim 2. For this type of manufacturing, it is optimal to dispose a strand or the like as a helix axially to the textile prior to folding, thus controlling the folding to a helical shape (S).

The tubing folding may be shaped to form unbroken rings (R) transversely to the tubing axis which will exhibit, in axial section, two sides with convex (E) and concave (A) arches in a symmetrical, parallel pattern, as set forth in claim 3. For this type of manufacturing, it is optimal to dispose strands or the like as rings axially to the textile prior to folding, thus controlling the folding to unbroken rings along the tubing (R).

The tubing folding may be in a uniform, corrugated (K) pattern axially to the tubing, where the distances between the concave (A) and the convex (E) arches will be uniform, as set forth in claim 4.

The tubing folding may be in an uneven, corrugated pattern axially to the tubing, where the distances between the concave (A) and the convex (E) arches will be different, as set forth in claim 5. The tubing aperture and external diameter may be constant axially to the tubing, as set forth in claim 6. This is optimal, for example at mounting, where mounting sockets at either end of the tubing have uniform dimensions.

The tubing aperture and external diameter may be decreasing or increasing axially to the tubing, as set forth in claim 7. This is optimal, for example at mounting, where mounting sockets at either end of the tubing have different dimensions.

The textile (T) of the flexible tubing may be shaped to form a tubing at the actual processing, as set forth in claim 8. It may, for example, be wool felt felted over a rod.

The textile (T) of the flexible tubing (T) may be shaped to form a tubing by taking a finished processed plate length of the textile and subsequently joining it to form a tubing, as set forth in claim 9. Said joining may be effected by sowing, gluing, or other usable methods.

The invention will be explained in more detail in the following description, reference being made to the drawings, where: Figure 1 is a perspective view of the flexible tubing with uniform, ring-shaped corrugations.

Figure 2 is an axial section through a side of the flexible tubing, showing the composition of the materials.

Figure 3 is an axial section through the flexible tubing, showing a helical solution (S) and a ring-shaped solution (R), respectively.

Figure 4 is an axial section through the flexible tubing, showing the flexible tubing at bending.

DESCRIPTION The flexible tubing functions in that it has corrugations (K) controlling the tubing movements, and avoids center-wise collapse at acceptable bending. At bending, this functions in that the corrugations (K) in one side of the tubing are compressed (Z), and that in the opposite side the corrugations (U) are unfolded, and thus it is avoided that the force impact compresses the aperture. At folding, the corrugations (K) of the entire tubing are compressed, and at unfolding, the corrugations (K) of the entire tubing are likewise unfolded.

Upon force impact along the tubing, the tubing aperture will collapse, but due to the soft structure (T) the tubing will get no fractures, and in case of shorter impacts it will easily be able to reassume its original shape upon end of impact. It may be necessary to press the tubing back to its original shape, depending on how strong the impact was. The soft structure (T) of the flexible tubing makes it fully compressible from all sides, without occurrence of fractures.

The flexible tubing is made from textile (T), shaped to form a tubing either from the actual textile processing, or by joining a cut-out length of textile plate to form a tubing. Said joining may be by way of stitching with thread, gluing, or other usable joining methods, depending on the intended use of the finished tubing.

After joining, the textile tubing (T) is disposed on a rod having dimensions matching the internal dimensions of the textile tubing. Method is chosen depending on whether the corrugations (K) of the tubing are to be uniform, helical (S), unbroken rings (R), or are to have an uneven pattern along the tubing. In the case of controlled corrugations (K), it will be necessary to dispose a strand or the like at the individual foldings. The textile is subsequently folded over the rod by pressing it together along the rod, the textile alternatingly being folded towards and away from the axial center of the tubing, thereby creating corrugations (K) internally and externally axially to the tubing.

In the case of wool or felt, the textile (T) is either boiled or steamed so as to retain its shape after removal of any strands from tubing.

Subsequently, the textile is treated, for example by dipping it into liquid latex (L), such that the entire textile gets soaked with the latex, after which it is remounted on the rod until dry. Depending on the construction of the tubing with the thickness, density, and type of textile relatively to thickness and kind of the treatments (L), the tubing may have many different degrees of softness that may be useful for different types of application. For mobile fittings in the ventilation trade, the tubing has optimally a soft structure of a relatively thin wool-textile (T) with a latex (L) and/or silicone treatment, which affects the flexibility minimally, but which imparts extra strength to the flexible tubing structure, encapsulates loose fibers, and increases air density and the air flow in the tubing.