Universal eversion tube with pressed-out ends and method for producing same

Abstract

The invention proposes a universal eversion tube with pressed-out ends for mounting on a wheel, a rim or a guide, obtained or obtainable by the following steps: • (a) providing a tube preform which is open at both ends and is equipped with a preferably central valve; • (b) providing two pressing devices; • (c) providing a vulcanizing device; • (d) inserting the two open ends of the preform into a respective one of the two pressing devices and closing the two ends by pressing them together; • (e) introducing the pressed-together preform into the vulcanizing device and vulcanizing the two pressed-together ends; • (f) removing the pressing devices; • (g) everting the two pressed-together ends into the finished eversion tube obtained in this way. • The invention also relates to a method and a device for producing the universal eversion tube.

Description

UNIVERSAL REVERSE HOSE WITH CRIMPED ENDS AND ITS MANUFACTURING PROCESS FIELD OF THE INVENTION

[0001] The present invention is in the field of means of transport and relates to a universal hose with crimped and folded ends, a method for its production and an associated press. TECHNOLOGICAL BACKGROUND

[0002] A bicycle inner tube is a container filled with compressed air that seals the tire (the rim) from the inside to prevent pressure loss if the rim isn't suitable for tubeless tires. It's part of bicycle tires and is made of butyl rubber, formerly also rubber.

[0003] Bicycle inner tubes have a long history: the first patent for an air-filled rubber tire was filed by Dunlop in 1888, followed a year later by Michelin with the replaceable inner tube for bicycles, and the vulcanization of rubber had already been invented by Goodyear in 1839. Since the time of these pioneers of tire development, time has not stood still, as the extensive state of the art technology demonstrates.

[0004] Among the most important developments in recent years are bicycle tubes that are not self-contained, but have two ends, usually sealed with caps. These new types of bicycle tubes are also inserted into the tire, expanding during inflation and eventually butting up against the caps to fill the tire. STATE OF THE ART EP 2704909 B1 (GAADI) relates to a tube for mounting on a wheel, a rim or a guide, which is circular, oval, ellipsoidal or otherwise rounded and is not continuous but has at least two ends. From EP 2693086 B1 (GAADI) a wheel tube for complete covering of a rim is known, which is not closed in itself, but has two ends, which is essentially characterized in that the two end caps and / or the tube have a non-constant wall thickness, so that they deviate from the circular shape with respect to their outer cross section when inflated. OBJECT OF THE INVENTION

[0005] Hoses that are not self-contained but have two ends consist, in simplified terms, of a center piece, both ends of which are closed with caps. The connection between the center piece and the two caps, which are usually made of different materials, is achieved by vulcanization. To compensate for the irregular running characteristics of such hoses caused by the different materials, the hose and caps usually have different wall thicknesses.

[0006] However, the disadvantage is that the production of the tubes requires special logistics for the various components and requires a high level of technical effort. Therefore, the objective of the present invention was to provide a non-closed inner tube for covering wheels, rims, or guides that is characterized by comparably good running properties but is easier to manufacture.

[0007] Another disadvantage is that the tubes must be of different lengths depending on the diameter of the wheel they are intended for. A further challenge to be solved was therefore to provide a universal tube that, in the spirit of "one size fits all," is suitable for rims of different diameters from 6 to 29 inches. DESCRIPTION OF THE INVENTION

[0008] A first object of the invention relates to a universal sleeve with crimped ends for mounting on a wheel, a rim or a guide, obtained or obtainable according to the following steps: (a) providing a hose blank open at both ends and equipped with a valve preferably arranged centrally; (b) providing two pressing devices; (c) providing a vulcanization device; (d) inserting the two open ends of the blank into one of the two pressing devices and closing the two ends by pressing; (e) introducing the pressed blank into the vulcanising device and vulcanising the two pressed ends; (f) removing the pressing devices; (g) Inserting the two pressed ends into the finished everting tube.

[0009] Figure 1 shows a section through a hose according to the invention (top) as well as a detail of a crimped end (left) and the valve area (right).

[0010] Surprisingly, it was found that the tube according to the invention fully meets the requirements mentioned above. This is explained below with reference to Figures 2 and 3, which each show a rim with a tube in an empty and filled state.

[0011] First, Figure 2 shows that the tube is very easy to install when empty due to its short overall length. Because it is folded inward, it can adapt to a wide variety of wheel and tire sizes when extended, i.e., when inflated, making it universally applicable.

[0012] Figure 3 shows the hose in its filled state. This is where both ends meet. The special inwardly folded shape of the hose ends creates a hollow space at the junction, allowing for smooth unwinding. If the ends had a closure plate, such as a cap according to the state of the art, the resistance of the hard plate would have a noticeably disruptive effect on unwinding. A further advantage of this design is that the space at the junction is better filled, since closure caps counteract transverse expansion. H first I procedure

[0013] Another object of the present invention relates to a method for producing a universal everting tube with pressed ends for mounting on a wheel, a rim or a guide, obtained or obtainable according to the following steps: (a) providing a hose blank open at both ends and equipped with a valve preferably arranged centrally; (b) providing two pressing devices; (c) providing a vulcanization device; (d) inserting the two open ends of the blank into one of the two pressing devices and closing the two ends by pressing; (e) introducing the pressed blank into the vulcanising device and vulcanising the two pressed ends; (f) removing the pressing devices; (g) Inserting the two pressed ends into the finished everting tube.

[0014] For the production of the claimed universal hoses, blanks are used which are usually made of synthetic butyl rubber, less frequently latex, and typically have a length (I) of about 50 to about 100 cm and in particular about 60 to about 70 cm. The nominal diameter (d) of the blanks can be about 3 to about 8 cm and in particular about 5 cm. Furthermore, hose blanks are regularly used which have a Wall thickness (a+b) of approximately 1 to approximately 3 mm. Reference symbols (a) and (b) refer to the case where the wall thickness of the hose is not constant along its length. In such a case, (a) represents the smallest and (b) the largest thickness. In the case of the present invention, however, the wall thickness is preferably constant, i.e., (a) and (b) are equal.

[0015] Figure 4 shows a cross-section of a hose blank whose ends have not yet been crimped.

[0016] It has also proven advantageous to use hose blanks that are talcum-coated inside and out. Talcum acts as a release agent during the production of the blanks and prevents them from sticking together during the extrusion process. However, the talcum can also be disruptive when pressing the ends together. Therefore, it is recommended to treat the ends of the hose blanks with a solvent before pressing. This not only cleans the ends, but also dissolves the material on the surface, facilitating a tight pressing.

[0017] Figure 5 shows a hose blank with the pressing area marked.

[0018] A key aspect of the invention is that smooth running of the inner tubes is achieved even without the use of closure caps and the associated changing thickness of the tube material. As explained, this is achieved by the special shape of the tube, namely the hollow space that forms when the ends are folded out. However, the applicant has found that running behavior can be further improved by adjusting the pressing thickness (e), i.e. the thickness of the inner tube at the pressing point, to a defined range calculated using the formula 0.4*(a+b). For a tube with a wall thickness of 1 mm, the optimal pressing thickness would therefore be 0.4 mm.

[0019] In the next step, the ends are sealed by vulcanization. This process typically takes place in an autoclave. It has proven advantageous to keep the pressed hose blanks clamped throughout the entire vulcanization phase, i.e., the hose is placed in the autoclave together with the two pressing devices ("press clamps").

[0020] In the final step, the now vulcanized hose blanks are placed in a forcing guide, and both ends are forcing in by inserting two forcing pistons from both sides. The forcing process is preferably controlled so that a cavity of approximately 1 to approximately 5 cm, and preferably approximately 2 to approximately 4 cm, remains between the forcing ends.

[0021] The procedure is explained in detail below using Figures 6 to 9:

[0022] Figure 6 shows the hose blank according to Figure 4, with the two ends now in the pressing device.

[0023] Figure 7 shows the hose with the crimped ends after vulcanization; the two crimp clamps are now removed.

[0024] Figure 8 shows the vulcanized hose blank in the inversion guide; inversion pistons move in from both sides and invert the hose, creating a hollow space in the center.

[0025] Figure 9 shows the final product, the universal sleeve with crimped ends.

[0026] It should be noted that the two open ends of the hose blank can also be pressed and vulcanized one after the other; this then requires only one pressing device, which is used alternately. Even such a more complex, and thus inferior, embodiment is encompassed by the inventive concept. Device for crimping ends of hose blanks

[0027] Another object of the invention relates to a device for crimping the ends of hose blanks, which is characterized by two pressing plates movably arranged in a holder, which can be moved toward each other, wherein the pressing gap created between the two plates has a pressing thickness (e) of 0.4*(a+b). Such a device is also shown, for example, in Figure 7, detail "Z".

[0028] It is advantageous to conduct heat to the joint during the vulcanization process with as little loss as possible. Therefore, at least the two movable press plates are preferably made of a material with good heat conduction, particularly aluminum.

Claims

PATENT CLAIMS 1. Universal sleeve with crimped ends for mounting on a wheel, rim or guide, obtained or available according to the following steps: (a) providing a hose blank open at both ends and equipped with a valve preferably arranged centrally; (b) providing two pressing devices; (c) providing a vulcanization device; (d) inserting the two open ends of the blank into one of the two pressing devices and closing the two ends by pressing; (e) introducing the pressed blank into the vulcanising device and vulcanising the two pressed ends; (f) removing the pressing devices; (g) Inserting the two pressed ends into the finished everting tube.

2. A method for producing a universal sleeve with crimped ends for mounting on a wheel, rim or guide, obtained or obtainable according to the following steps: (a) providing a hose blank open at both ends and equipped with a valve preferably arranged centrally; (b) providing two pressing devices; (c) providing a vulcanization device; (d) inserting the two open ends of the blank into one of the two pressing devices and closing the two ends by pressing; (e) introducing the pressed blank into the vulcanising device and vulcanising the two pressed ends; (f) removing the pressing devices; (g) Inserting the two pressed ends into the finished everting tube.

3. Process according to claim 2, characterized in that hose blanks are used which have a length (I) of about 50 to about 100 cm.

4. Process according to claims 2 and / or 3, characterized in that hose blanks are used which have a nominal diameter (d) of about 3 to about 8 cm.

5. A process according to at least one of claims 2 to 4, characterized in that hose blanks are used which have a wall thickness (a+b) of about 1 to about 3 mm.

6. A process according to at least one of claims 2 to 5, characterized in that hose blanks are used which are talcum-coated inside and out.

7. A method according to at least one of claims 2 to 6, characterized in that the ends of the hose blanks are treated with a solvent before pressing.

8. Process according to at least one of claims 2 to 7, characterized in that the ends of the hose blanks are pressed to a pressing thickness (e) of 0.4*(a + b).

9. Process according to at least one of claims 2 to 8, characterized in that the vulcanization is carried out in an autoclave.

10. A method according to at least one of claims 2 to 9, characterized in that the ends of the hose blanks are left in the pressing device during vulcanization.

11. A method according to at least one of claims 2 to 10, characterized in that the vulcanized hose blank is placed in an inversion guide and the two ends are inverted by inserting two inversion pistons on both sides.

12. Method according to at least one of claims 2 to 10, characterized in that the invagination process is controlled so that a hollow space of about 1 to about 5 cm remains between the invaginated ends.

13. Device for pressing the ends of hose blanks, characterized in that it comprises two pressing plates which are movably arranged in a holder and can be moved towards each other, the pressing gap created between the two plates having a pressing thickness (e) of 0.4*(a+b).

14. Device according to claim 13, characterized in that at least the two movable pressing plates consist of a material with good heat conduction.

15. Device according to claim 13 and / or 14, characterized in that at least the two movable press plates are made of aluminum.

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