DE202017003752U1 - Ski core made of fiber-stabilized stone material - Google Patents

Abstract

Arrangement of a ski with a core of fiber-stabilized earthenware, characterized in that the core is partially sheathed or fully fiber-coated by the fiber is biased and has a geometric shape whose height profile seen in the longitudinal direction is higher in the middle, as at the two ends.

Description

The selection of materials in ski processing is one of the core issues in the construction of skis. In the past, wooden skis were built. At the beginning of the development of the ski, this was certainly expedient because at the beginning of the development there was no easier to process material to quickly reach the desired goal of developing the art of skiing at all. Attaching steel edges has been relatively easy with screws, to name only one of the developmental steps that have proven to be a necessity for further development of the sport.

In this phase of development, of course, quickly turned out that wood has its limits, for example in the mechanical load capacity. For this reason, one soon began to look for other materials, for example steel, which replaced the wood completely in a row.

In the case of steel, too, it soon became apparent that there were limits of loading capacity, and in this case the continuous load imposed a limit. Steel loses stiffness during continuous load changes and becomes "tired", which manifests itself in the fact that the ski loses the necessary preload and is completely lost after some time of use. On the other hand, such skis made of steel were relatively heavy compared to wooden skis.

In the next step, aluminum was used, which is much lighter than steel, which is reflected in the specific gravity, which is lower by a factor of 2.8 than that of steel.

For this reason, such skis were again significantly lighter and had the disadvantage that the plastic deformability of aluminum does not have the same quality as that of steel, so that even with a single overload such skis bend very quickly completely, resulting in Consequence has that an overload unlike the steel causes the ski does not return to its original shape, as it is locally partially bent by overload, as an overload on steel is distributed over a wider range of geometry and therefore not directly local expresses, but as mentioned rather leads to a permanent fatigue.

A bent aluminum ski can only be disposed of.

In the next step, plastics were tried which compensate for the disadvantages described above almost without exception and also remain permanently in the desired shape, especially when the plastics are stabilized with the aid of fiber materials such as glass fibers, stone fibers and carbon fibers. As binding resins, the usual synthetic resins are used, either thermosets or thermoplastic composite resins.

In the next step, hybrid structures were tried, which again brought the materials such as wood, steel and aluminum into play, but now only partially and by stabilization with the above-mentioned fiber-stabilized plastics such as GRP and CFRP, or also stone fiber layers stabilized with synthetic resin and the remaining materials are glued.

A completely new stage in ski construction is the use of stone, which was tried out in the next step, because a fiber sheathing of natural stone means that it can no longer break and play its elasticity, which it has under pressure or bias. A typical granite has the same modulus of elasticity as aluminum and also the same specific gravity as aluminum, if it is provided with a sheath of carbon fibers. The permanent elasticity is also given, as long as the yield and pressure limits of the natural stone are not exceeded, which is prevented by the bias with carbon in Zuglastfall. Granite has a similarly high compressive strength in the plastic range, such as steel. How natural stone can be made flexible without fracture, for example, in the EP 106 20 92 described. This leads to the fact that natural stone also in the Skibau, like in the EP 106 20 92 described, can be used. The first skis with a core of coated stone are already being sold on the market. The advantage was that the natural stone brought a good damping, which can be attributed to the damping of granite of 2%, in the ski, which had a pleasant smoothness, fast vibration reduction and a good shock absorption result.

For this purpose, the stone is brought into the ski with this invention in the entire length in order to reduce the vibrational energy over the entire length of the ski.

This new application is about the appropriate design of such cores of coated stone over the entire length of the ski. Since the stone remains fracture-free only under sufficient bias, the bias in this process is a prerequisite to keep the stone au deer entire length permanently elastic and protect against fatigue by hairline cracks, even if he has a relatively strong ridge in the middle.

To achieve this, the stone core at the top of the ski and at the end, however, must be so thin that it fits into the normal geometry of a ski fits into it and finds its place in conjunction with the other materials required.

For this reason, the stone core is made of a stone plate, as in the EP 106 20 92 described, cut out with the water jet following a cross-sectional geometry of the desired ski shape and then fully coated with the aid of fiberglass and CFRP or basalt fibers.

So that the stone core, which is very thin at the ends, does not break when cutting with water steel, the stone slab is preferably pre-stabilized beforehand on both sides with fibrous material. The thickness of the plate depends on how strong the stone core in the ski is to contribute to stability and damping. There are many possible variations to process narrower or wider stone cores and fill the rest with light other materials or even cavities, which can also be foam filled. Subsequently, the cover layers are applied to such a body and incorporated the usual steel edges. Apart from natural stone, artificial stone can also be used, such as resin-bound stone flours, ceramics, high-strength concrete and even glass-ceramic or glass, all of which, however, have a different damping behavior. For this reason, a compact granite from the current point of view is a well-fitting and easy to produce material for the composite described. In principle, all pressure-stable minerals, which are referred to below as stoneware. Special stabilization properties arise when unidirectional fiber webs are used at least on the underside of the earthenware core, in order to ensure optimal prestressing of the earthenware due to the high rigidity of such clutches. If the carbon bridge front and rear is provided with a power connection, the stone core can also be heated, which increases the bias during the ride. Since the fibers have a high ohmic resistance, but the fiber cross-section is relatively small, even at a low voltage, a relatively high current can be brought to flow, which heats the fiber first and then the stone core in the next step. Since the coefficient of expansion of the stone is higher by factors than that of the fiber, the result is automatically a natural reinforcement of the preload, the entire ski becomes stiffer.

The shows a middle-longitudinal section through such a stoneware core ( 1 ), which with carbon fiber material ( 2 ) and a side view of the sheathed core with the carbon layer 2 on the surface. The top of the ski core is shown on the left and the ski end on the right. The shows a 90 ° cross section AA through the longitudinal section in and a 90 ° total cross section BB through the core in side view , as in the top or bottom view of the sheathed core with the carbon layer ( 2 ) on the surface.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1062092 [0009, 0009, 0013]

Claims (8)

Arrangement of a ski with a core of fiber-stabilized earthenware, characterized in that the core is partially sheathed or fully fiber-sheathed by the fiber is biased and has a geometric shape whose height profile seen in the longitudinal direction is higher in the middle, as at the two ends. Arrangement according to claim 1, characterized in that the height profile of the core in the longitudinal direction continuously corresponds to the varying thickness of the ski to be stabilized. Arrangement according to claim 1 and 2, characterized in that the height profile of the core continuously corresponds to the varying thickness of the ski to be stabilized minus the lower and upper cover layer or the lower and upper cover layers. Arrangement according to claim 1 to 3, characterized in that the fiber-stabilizing sheath is carried out with the aid of carbon fibers, glass fibers, stone fibers or a mixture of these fibers. Arrangement according to claim 1 to 4, characterized in that in a layer of the sheath is a carbon layer or carbon fiber-containing layer having at least two current injection necessary for current flow to heat the ski core by current flow in the fiber. Arrangement according to claim 1 to 5, characterized in that the earthenware is a natural stone, gneiss, marble, basalt, quartzite or artificial stone, concrete, ceramic material, glass or glass ceramic. Arrangement according to claim 1 to 6, characterized in that the fiber-stabilizing adhesive-like synthetic resin compound is a thermosetting or thermoplastic resin. Arrangement according to claim 1 to 7, characterized in that at least one of the stabilizing fiber layers on the underside of the earthenware core is a unidirectional Fasergelege.

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