DE8806888U1 - Bead core for foldable bicycle tires - Google Patents

Description

Tap 9421/88

"Bead core for folding bicycle tires"

The invention relates to a bead core for foldable bicycle tires, consisting of plastic fibers, in particular polyester - preferably aramid fibers, which are wound into a ring and impregnated with a binding agent.

Such bead cores are known; to date, a large number of fibers are wound into a bead core and impregnated with a binding agent, for example a rubber solution or the like.

The disadvantage of this design is that the bead core thus formed does not meet the requirements in terms of dimensional stability. The load-bearing capacity of the bead core is also not sufficient, so that bicycle tires equipped with such bead cores jump off the rim of a bicycle equipped with them when high excess pressure is applied.

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Based on this state of the art, the invention is based on the object of creating a bead core of the type specified which meets the highest requirements in terms of dimensional stability and which, after installation in a corresponding tire, also ensures a better fit of the tire on the rim even in the event of considerable overpressure.

To solve this problem, it is proposed that the core consists of several fibers wound in several layers one above the other and next to each other, with each fiber being wound to form a core element with several turns wound one above the other, several such core elements being arranged next to each other and the core elements arranged next to each other being wound in opposite directions in a Z-S lay.

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The fact that the bead core is formed from several core elements arranged next to one another, which have several turns one above the other and which are wound in opposite directions, counteracts the fact that the individual fibers are basically twisted, so that when wound in opposite directions an increased tendency to twist is created, which is disadvantageous both in terms of dimensional accuracy and in terms of the installation of the bead core.

Preferably, each core element is wound in at least three and at most five layers.

Furthermore, it is preferred that at least three and at most five core elements are arranged next to one another.

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■ '.II II II· <· ··

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A preferred embodiment consists in that each core element is wound in four layers and four core elements are arranged next to each other.

This square design is advantageous in terms of the desired functional properties.

It is further preferred that each fiber of each core element is wound with a twist rate of 50 to 100 per meter, preferably 80 per meter.

A preferred further development is that each fiber is made of a twisted single fiber (filament yarn) with a weight of 1610 grams per 10 km length.

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It is particularly preferred that the individual fibers consist of high-strength aramid of in particular 85 N/tex.

A particularly preferred development is that the core elements are tightly fitted together and connected to one another by means of adhesive.

It is preferably provided that the adhesive is curable and has a softening temperature below the ripening vulcanization temperature (approx. 16O ⁰ C to 180 ⁰ C).

Furthermore, it is intended that the adhesive is based on polyurethane and has a softening temperature of approximately 80° to 100 ^° C.

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Finally, it is intended that the adhesive is air-curing.

The manufacture of such a bead core can be carried out in such a way that first a single core element is wound from a single fiber made of aramid, for example in four layers on top of each other.

Four such elements are then wound or arranged next to each other, with the ^neighboring core elements being wound in counter-lay. The individual fibers can be coated with adhesive, for example with a polyurethane-based adhesive, at the beginning of the winding process, so that an intimate connection of the individual fibers and also the inner layers of a core element and the neighboring core elements is achieved.

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It is advantageous that the corresponding adhesive is air-curing, so that the finished bead core hardens after a short time and can therefore be stored and transported for a practically unlimited period.

It is important that the softening temperature of the adhesive is significantly below the tire vulcanization temperature, so that the bead core softens and can be thermoplastically deformed when installed in the bicycle tire.

Regarding the strength of the preferably selected aramid fiber, there is a dependency on the gram weight per unit length (dtex), since when using high-strength aramid fibers, the gram weight per unit length can be lower than when using less strong aramid fibers.

It should also be noted that when polyurethane is used as an adhesive, it has an excellent affinity to the fiber material, namely aramid

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and on the other hand also to the rubber

Material of the bead core to be fitted:

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An embodiment of the invention is shown in the ■

leichen and briefly described below. ^: -\ E s &zgr; eigt: >]

Fig. 1 shows a bead core according to the invention in;

Opinion;

Fig. 2 also in section II-II of Fig. 2
seen.

I)The bead core for foldable bicycle tires consists
in the example of four side by side
Arranged core elements 1 to 4, each
Inner element made of an aramid fibre (filament yarn)
and several wound on top of each other
has turns 5 to 8.

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The core elements 1 to 4 arranged next to each other are each wound in opposite directions in a Z-S lay. Each fiber of each core element 1 to 4 is wound with a lay rate of 80 J/m. Each twisted individual fiber has a weight of 1610 dtex. The individual fibers preferably have a strength of 85 N/tex.

The individual core elements 1 to 4 are joined extremely closely together and so are the turns 5 to 8 of each core element as well as the fibers in the winding lay using a polyurethane-based adhesive. In this way, an approximately square structure is created in cross-section, as can be seen from Figure.

The adhesive is air-curing, so that the finished bead core can be stored and transported.

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When installing the bead core in a corresponding bicycle tire, the adhesive softens during vulcanization well before the vulcanization temperature is reached, so that the bead core cannot be thermoplastically deformed before installation in the tire. After the finished tire has cooled to ambient temperature, the bead core has hardened again.

|)The invention is not limited to the embodiments, but is variable in many ways within the scope of the disclosure.

All new individual and combination features disclosed in the description and/or drawing (Dffe:ibe~ ^| -en are considered essential to the invention.

Claims (1)

PATENT ATTORNEYS * .'&iacgr;". . I i *·*. . ". * * AWfenjeichen: CONRAD COOKING··'"'"··"&mdash;''··"··*
DiPL-&idiagr;&Ngr;&bgr;. CONRAD-JOACHIM KÖCHLING Reyer Straße 135, 5800 Hagen Name: Hahn GmbH. & Co. Call (02331) &bgr;« &mgr;+ 85033 Altenaer Str. 41 Telegrams: Paterrtkochllng Hagen Accounts: Commerzbank AQ. Hagen 5992 Nachrodt (Bank code 450 «0 42) 3 515 085 Sparkasse Hagen 10001200 ________ __ Posächeck: Dortmund 5988-460 ~ VNR: JLL_J_L._Ü _{Ud No} 9421/88 CJK/G. 24 May 1988 Protection claims: 1. Bead core for foldable bicycle tires, consisting of plastic fibers, in particular polyester preferably aramid fibers, which are wound into a ring and impregnated with binding agent, characterized in that the core consists of several fibers wound in several layers one above the other and next to each other, whereby one fiber is wound into a core element (e.g. 1,2,3,4) with several turns wound on top of each other (e.g. 5-8), several such core elements (e.g. 1-4) are arranged next to each other and the core elements arranged next to each other are each wound in opposite directions in a Z-S lay. Tap 9421/88 2. Bead core according to claim 1, characterized in that each core element (e.g. 1, 2, 3, 4) is wound in at least three and at most five layers. 3. Bead core according to claim 1 or 2, characterized in that at least three and at most five core elements (eg 1-4) are arranged next to each other
are arranged. Bead core according to one of claims 1 to 3,
characterized in that each fiber of each core element is wound with a twist rate of 50 to 100 per meter, preferably 80 per meter. Tap 9421/88 Bead core "SC he .1 ^np &Pgr;1 of the A &eegr; s: &eegr; riirh &rgr; 1 his 4 . characterized in that each fiber is formed from a twisted single fiber (filament yarn) with a weight of 1610 grams per 10 km length. 6. Bead core according to one of claims 1 to 5, characterized in that the individual fibers consist of high-strength aramid of in particular 85 N/tex. 7. Bead core according to one of claims 1 to 6, characterized in that the core elements (e.g. 1-4) are tightly fitted together and connected to one another by means of adhesive. Tap 9421/88 t. Bead core according to one of claims 1 to 7, characterized in that the adhesive is curable and has a softening temperature below the tire vulcanization temperature (approx. 160 ⁰ C to 180 ⁰ C). Bead core according to one of claims 1 to 8, characterized in that the adhesive f is based on polyurethane and has a softening temperature of about 80° to 100 ⁰ C. 10. Bead core according to one of claims 1 to 9, characterized in that the adhesive is air-curing.