CA2165677A1 - Ski - Google Patents

Abstract

The invention concerns a ski having layers of transparent plastic material. The entire ski body, i.e. the ski itself, is transparent at least in given areas.

Description

Ski The invention relates to a ski having layers of transparent plastic material.
Besides the technical properties of a ski and in particular those relating to the way in which the ski runs, the appearance of the ski is also having an increasing influence on the purchase decision. In that respect there are various means, including those of a technical nature which are used to influence the appearance of the ski. Thus for example transparent layers are already used as cover layers for the top side of the ski or as running surface coverings for protecting the decoration or decorative layers which are disposed either on the rear side of the transparent layer or beneath the transparent outside layer.
The object of the present invention is to expand the use of transparent ski components, more specifically on the one hand to influence the appearance of the ski and/or on the other hand in order thereby also to achieve a technical effect.
In accordance with the invention that is achieved in that the entire ski body is transparent at least in a region-wise manner. There is therefore not just a surface layer or running surface layer that is transparent, in order to be able to see decorations, symbols or graphics which are disposed therebeneath or therebehind respectively, but in accordance with the invention the ski as such, that is to say in its entirety, is transparent, at least in a region-wise manner. That means in particular that the ski is transparent at least perpendicularly to the plane of the running surface over its entire cross-sectional height, which however does not have to be the case at all locations of the ski (accordingly "at least in a region-wise manner"). For example functional parts of opaque material, in particular metal, as in the case of alpine skis the steel edges, binding fixing parts or reinforcing elements, can form zones which are excluded from being transparent. It is also possible for decorative reasons or for identification purposes to provide in the ski body inserts which are opaque, that is to say not transparent, and which then form contrasting zones with respect to the transparent regions of the ski.
"Transparent" in accordance with the invention means not only clearly see-through but also translucent. A measurement in respect of transparency is the transmission coefficient r = ~d/~o (~0 = incident radiation intensity and ~d = transmitted radiation intensity). Therefore, in accordance with the present invention, those locations of the ski where the transmission coefficient in the visible spectral range is different from zero, for example is at least 10 % but preferably considerably above that value, are to be identified as "transparent". A light source which is disposed for example beneath the running surface of the ski should still at least be perceived as a gleam of light on the surface of the ski. The transparency can also be a "coloured" transparency, that is to say it does not have to extend over the full width of the visible spectrum. On the other hand however changes in colour due to radiation (light, UV) or ageing are rather undesired. Transparent materials which are of maximum stability in relation to radiation and ageing, in terms of their transparency, should therefore be used.
In contrast to the above-mentioned known state of the art it is not sufficient in accordance with the invention that only the surface layers comprise transparent plastic material, but also the inner components must be transparent at least in a region-wise manner, thus for example the load-bearing layers which can comprise glass fiber-reinforced plastic material by transparent glass fibers being bonded with transparent synthetic resin.
If the reinforcing inlays partially comprise transparent glass fibers and partially opaque carbon fibers, it is also possible to achieve particular effects from the technical and design-configuration points of view. The core zones of the ski can be kept transparent either by using transparent core material or by forming internal cavities. For that purpose for example the load-bearing ski body may be formed from one or more hollow bodies whose walls (at least in part) comprise transparent glass fiber-reinforced plastic material. Another possibility would be to arrange a honeycomb core with upright honeycomb cell walls which then also permit a view therethrough perpendicularly to the running surface of the ski if the honeycomb cell walls themselves do not comprise transparent material. It will be appreciated however that the honeycomb cell walls may also comprise plastic material which is possibly glass fiber-reinforced.
The requirement in respect of transparency also applies in relation to any adhesives which may be used for joining the individual layers, in which respect it will be noted that it is also possible to use non-transparent S adhesives in a zone-wise manner.
The invention not only makes it possible to produce skis of hitherto unknown appearance but it also guarantees a view into the interior of the ski in order to detect any workmanship flaws, for example defective orientation of the glass fibers or air bubbles in hardened synthetic resin.
Composite fiber plastic materials with directed reinforcing fibers can fully exhibit their excellent material properties such as high strength, stiffness and resistance to corrosion, only when the arrangement is such that the fibers are oriented in accordance with the loading. Just minor deviations in the fiber direction relative to the loading direction give rise to serious losses in terms of the strength of the component. Hitherto monitoring the correct orientation of the reinforcing fibers during ski manufacture failed either for technological reasons or because the individual ski components did not permit an inspection (were opaque). The composite fiber materials were then intentionally over-sized in order to compensate for a possible loss of strength, although of course at the expense of overall weight.
The structure of a ski which is transparent in itself permits continuous monitoring of the fiber orientations and thereby makes it possible to achieve the optimised use of composite fiber materials, which in turn is necessary for lightweight constructions.
The invention can be applied to all kinds of skis (alpine skis, cross-country skis, water skis etc.), in which respect the term ski also embraces other pieces of equipment such as snowboards.
The invention is described in greater detail hereinafter by means of an embodiment with reference to the drawing.
Figures 1, 3 and 5 are views in cross-section of different embodiments of skis and Figures 2, 4 and 6 are the associated plan views of the skis.
Figure 1 is a view in cross-section of a ski which, with a suitable selection of material, in accordance with the invention, can be in the form of a transparent ski.
The ski shown in Figure 1 belongs to the general kind of shell-type skis and comprises a flat lower structural group with the running sole 1, for example of polyethylene, and the lateral steel edges 2. The interior of the ski is enclosed laterally and upwardly by a shell 3 of non-reinforced plastic material. The internal load-bearing structure of the ski is formed by a hollow body 4 with walls 5, 6 of fiber-reinforced thermoplastic or thermosetting plastic material. The inner hollow body 4 fills the internal space between the upper shell 3 and the lower structural group 1, 2 in such a way that the outside walls 5 bear against the inside walls of the shell 3 and the lower structural group 1, 2 respectively. The hollow body 4 also has perpendicular intermediate walls 6 which subdivide the interior of the hollow body 4 into three air-filled hollow chambers.
In order to achieve the transparency in accordance with the invention of the ski body, a transparent polyethylene is used for the sole 1 and a transparent plastic material, for example a UV-stabilised thermoplastic material such as for example thermoplastic polyurethane or polyamide is also used for the shell 3. Also used for the walls 5, 6 of the hollow body 4 are transparent synthetic resins, for example polyester resin or epoxy resin as a bonding agent for the fiber inlays, wherein the fiber inlays entirely or predominantly comprise transparent glass fibers.
Such a ski could then be of the appearance as shown in Figure 2, in plan view, in which case the ski body is transparent from above downwardly in the regions A, while the edge zones B, and also the tip and end regions C, D as well as the binding fixing region E appear non-transparent (opaque), more specifically as a result of the presence of the steel edges 2 and also the tip and end protection of metal and a reinforcing inlay or binding fixing plate in the binding fixing region. The tip protection could for example also consist of a so-called fit-on tip, in which case the fit-on tip can also be at least partially transparent and in particular can comprise transparent and preferably thermoplastic material.
Additional dark longitudinal strips also make their mark on the appearance of the transparent ski (Figure 4) if, as shown in Figure 3, for example longitudinally extending inserts or inlays 7 for example of synthetic resin-bound carbon fibers are arranged on the top side of the inner hollow body 4. In the case shown in Figure 3 the inlays 7 are of a triangular cross-section and are arranged over an intermediate wall 6.
The embodiment shown in Figures 5 and 6 also provides that the appearance of the transparent ski has dark opaque strips F which however are now formed by flat strip-shaped inserts or inlays 8 between the top side of the inner hollow body 4 and the shell 3. In addition, in the embodiment shown in Figures 5 and 6, also interwoven in the fiber reinforcements of the two lateral chambers, which fiber reinforcements also comprise a tubular glass fiber weave, are individual threads 9 of carbon fibers, for example disposed in an inclined position (in a helical configuration), which then appear as a dark zig-zag pattern or crossed pattern G.
Manufacture of a ski in accordance with the illustrated embodiments can be effected using a mold consisting of two mold halves, the ski being shaped ;n the cavity of the mold, involving the following process steps:
a) the components of the lower structural group (running sole and steel edges) are fitted into the recess of the first (lower) mold half;
b) flat fiber material portions impregnated with synthetic resin, in tubular form, are provided with internally disposed tubes of air-tight material and positioned in the mold, being for example laid onto the components of the lower structural group, which components have been fitted into the first mold half;
c) the possibly pre-shaped cover foil of plastic material is also positioned in the mold;
d) the second (upper) mold half with a mold cavity corresponding to the lateral and surface contour of the ski body is fitted onto the first mold half;
e) the internally disposed air-tight tubes within the tubular synthetic resin fiber material portion or portions are inflated with compressed air, in which case they expand, and the tubular synthetic resin fiber material portion or portions is or are also expanded and the foil bears against the inside wall of the second mold half; and f) the synthetic resin of the tubular synthetic resin fiber material portion or portions is hardened, while the internal compressed air pressure is maintained in the internally disposed air-tight tube or tubes, possibly with the application of heat.
After termination of the hardening operation the increased pressure produced by the compressed air in the tubes is released and the ski is removed from the mold. After the ski is removed from the mold, any edges of the cover foil which still project beyond the side surfaces of the lower component group are cut off. With suitable provision being made at the ski tip and/or the rear end of the ski, the tubes can be removed from the internal cavities of the hollow bodies which have now hardened, for the purposes of re-use thereof. If the tubes remain in the ski body they must be at least partially transparent, for example consist of transparent polyamide, having regard to the effect in accordance with the invention.
The illustrated embodiments of transparent skis and the described example of a possible production process are obviously not to be interpreted in a restrictive sense but only as individual examples of numerous possible ways of carrying into effect the inventive concept of a transparent ski.

Claims (5)

1. A ski having layers of transparent plastic material characterised in that the entire ski body is transparent at least in a region-wise manner.

2. A ski as set forth in claim 1 characterised in that the ski is transparent at least in a region-wise manner perpendicularly to the plane of the running surface over the entire cross-sectional height of the ski.

3. A ski as set forth in claim 1 or claim 2 characterised in that the load-bearing internal components (4, 5, 6) of the ski at least partially comprise transparent glass fiber-reinforced plastic material.

4. A ski as set forth in one of claims 1 through 3 characterised in that the ski has opaque inserts (7, 8, 9) in a zone-wise manner.

5. A ski as set forth in one of claims 1 through 4 characterised in that the load-bearing ski body (4) is formed from one or more hollow bodies whose walls (5, 6) at least partially comprise transparent glass fiber-reinforced plastic material.