WO1994006524A1

WO1994006524A1 - Ski, in particular alpine or cross-country ski

Info

Publication number: WO1994006524A1
Application number: PCT/EP1993/002209
Authority: WO
Inventors: Werner Feichtlbauer
Original assignee: Hagan Yamaha Sport Ges.M.B.H.
Priority date: 1992-09-15
Filing date: 1993-08-18
Publication date: 1994-03-31
Also published as: EP0768911A1; JPH08501232A

Abstract

A ski, in particular an alpine or cross-country ski, consists of a core (1), a lower web (2), an upper web (3), a bottom (4) with or without lateral edges (5) arranged below the lower web, and a top covering foil (6) which extends as a semi-monocoque over the upper web (3) and both longitudinal lateral surfaces (7, 8) of the ski core (1) down to slightly above the running surface or down to the lateral edges (5), a thermoplastic filling material being located between the covering foil (6) and the ski core (1). An originally up to 80 % open-pored polyurethane hard foam is used as thermoplastic filling material (9) which can be permanently compressed under a pressure of 6 to 12 bars and at a temperature from 80 to 140 °C in the direction of compression. Preferably the filling material (9) is a strip of hard foam permanently pressed between the upper covering foil (6) and the upper web (3), and consolidated by an adhesive (13) which penetrates into the open pores of the foam body and is thermally cured.

Description

Skis, especially alpine or cross-country skis

The invention relates to a ski, in particular alpine or cross-country skis, consisting of a

- ski core;

- lower chord; - top chord;

- tread arranged below the lower chord with or without side steel edges; such as

- An upper cover film, which extends half-shell-like over the upper flange and the two longitudinal side faces of the ski core, to just above the tread or to the side steel edges, whereby

- Thermoplastic filling material is located between the cover film and the ski core.

Furthermore, the present invention relates to a method for producing such a ski.

A ski and method of the aforementioned type are known, inter alia, from EP-A-0 446 965, EP-A-0 428 886, EP-A-0 459 347, EP-A-0 461 453, DE-C-3 803 507 or DE-C-3 803 483. In the known constructions and methods it is essential that the filler material between the cover film and the ski core is a viscous and flowable material under pressure and temperature, which material is released into the ski form when pressed Areas or voids between cover film and ski core flows and this fills out (see, inter alia, DE-C-3 803 483, column 33, lines 14-17). The known construction and the known method allow the production of so-called "shell skis", which are characterized in that the cover film is half-shell-shaped over the upper flange and the two longitudinal side surfaces of the ski core, up to just above the tread or up to the lateral steel edges extends. The problem with the known construction or the known method is the removal of air enclosed between the cover film and the core. Special precautions must be taken for this. Nevertheless, the inclusion of air bubbles cannot be reliably avoided, with the result that after more or less long use of the ski they become visible to the outside in the form of bulges or dents.

Furthermore, in the known method it is necessary to match the amount of filler material exactly to the cavity to be filled between the cover film and the ski core, since the filler material is not or only slightly compressible. When changing batches, it is therefore quite possible that cavities are not filled in at some points, while excessive material accumulation occurs at other points. This creates tension nests that either become free when the ski is removed or after the ski has been used for the first time and lead to surface damage (dents or the like).

Because of the material properties of the known filler material, it is also not very possible to use the filler material to compensate for height differences within a predetermined shape between the cover film and the ski core. The filling material always escapes in areas of the least resistance. Therefore, it is not well suited for the aforementioned height compensation within the mold.

From the TITANAL ski lexicon, page 19, it is known to use polyurethane foam in ski construction as a ski filling. Would However, if this known material is exposed to higher pressures of up to 12 bar and / or higher temperatures of up to 140 ° C, destruction of the material could not be avoided. The known PU foams, such as those used as ski filling or for the production of ski cores, cannot be deformed under pressure and at a higher temperature. They are therefore also excluded from the aforementioned prior art as filler material.

The present invention is based on the object, based on the aforementioned prior art, of creating a ski which, because of its opening, permits a considerable reduction in the number of required forms and which is distinguished by permanent dimensional stability.

Furthermore, the present invention is based on the object of providing an efficient method for producing such a ski.

The above objects are achieved according to the invention by the characterizing features of claim 1 and claim 8.

The invention is characterized by a so-called "ski-in-ski principle". The construction according to the invention consists of an inner ski with a top flange, core, bottom flange and an outer ski with a cover film or shell, pressed and solidified hard plastic body, tread with or without steel edges. The inner ski consisting of the upper flange, core and lower flange is a fixed size, while the outer ski is variable owing to the inventive hard-plastic body, ie it can be adapted to the height differences between the upper flange and the upper ski shape in the longitudinal and transverse directions of the ski. The above-mentioned height differences are compensated for within the ski shape by more or less strong compression of the hard foam body. Influence on ski rigidity is therefore not exercised or only imperceptibly. The stiffness and stiffness distribution of the ski is determined solely by the structure and dimensioning of the ski core. The aforementioned outer ski is therefore primarily used only for the outer shape of the entire ski, without having a strong influence on the physical properties of the ski, such as rigidity, etc.

The fact that an originally up to 80% open-pore hard foam (TPU) is used as the filling material enables the aforementioned pressing without flowing away to the side. The open pores collapse under the pressure within the ski shape, primarily in the direction of pressure. The permanent solidification of the compressed foam is obtained by impregnating the same with adhesive, in particular the usual epoxy adhesive. According to the method according to the invention, the up to 80% open-pore foam body, in particular hard foam body, is coated on all sides with epoxy adhesive. This penetrates into the open pores of the plastic body, in particular under the pressures and temperatures applied within the ski shape. As a result, the foam body is literally impregnated with epoxy adhesive. When the adhesive hardens, the pressed foam body is correspondingly hardened with simultaneous connection of the same to the ski core or upper flange on the one hand and to the half-shell-shaped cover film on the other hand.

Any air pockets between the cover film and the ski core are also absorbed by the still open pores of the foam body, without these air pockets showing any external effect. The open porosity of the foam used according to the invention is therefore extremely advantageous both for the penetration of adhesive and for the absorption of enclosed air. No special precautions have to be taken for the escape of air from the area between the cover film and the ski core. in the Otherwise, the escape of air is additionally facilitated by the fact that the cover film, in contrast to the process according to DE-C-3 803 483, is assigned to the upper and not the lower mold.

The adhesive is preferably applied to the foam body in an amount of approximately 80 to 200 g / m ² .

The rigid foam body prefabricated according to the invention preferably consists of TPU = thermoplastic polyurethane. It has a constant height over the length and width of the ski or is double-wedge-shaped in accordance with the usual shape of the ski core. Ultimately, this primarily depends on the height difference to be compensated for between the upper shape and the upper flange.

Due to the variability of the so-called "outer ski", the ski according to the invention can be made with considerably fewer ski shapes than in the prior art.

Moreover, the open porosity of at least about 60%, preferably up to 80%, according to the invention prevents the filling material from escaping laterally during the pressing. Rather, the high degree of open porosity means that the filling material is literally folded together in itself or collapses in itself, primarily in the printing direction. Therefore, it is also not necessary to calculate or provide lateral free spaces for displaced filler volume, as is the case with the prior art.

A filler block consisting of a thermoformable hard urethane and / or isocyanurate groups is preferably used as the filler material with a density of over 100 kg / m ³ . Aliphatic, cycloaliphatic, aromatic and heterocyclic serve as starting compounds for such foams Polyisocyanates or mixtures thereof. Suitable isocyanates are, for example, 1,4-tetramethylene diisocyanate, 1,12-dodecandyocyanate, cyclobutene-1,7-diisocyanate, phenylene diisocyanates, tolylene diisocyanates, diphenylethane diisocyanates, diphenyl methane diisocyanates, naphthylene diisocyanate diisocyanate diisocyanate, hexane diisocyanate, groups, urethane groups, isocyanurate groups, urea groups, allophanate groups or biuret groups. Preferred isocyanates, such as 2,4- and / or 2,6-tolylene diisocyanate, 4,4 'and / or 2,4-diphenylmethane diisocyanate, and modified isocyanates derived therefrom are used.

Mixtures of at least hydroxyl-containing polyethers and polyesters with a molecular weight of 400-10,000 are used as further starting compounds. Mixtures with an OH number of at least 400 are preferred.

Water and / or volatile hydrocarbons or halogenated hydrocarbons, such as methylene chloride or trichloromonofluoromethane, are usually used as blowing agents.

All customary catalysts can be used as catalysts for the polyaddition reaction, for example organometallic compounds such as tin octanoate, dimethyltin laurate, dibutyltin laurate, dibutyltin acetate, lead oleate, vanadium pentoxides or mixtures thereof, tertiary amines such as triethylene diamine, dimethylhexamine, triethylamine, triethylamine -Ethyl-piperidine, tetra ethyltetramethylene diamine or mixtures thereof.

The polyurethane foam can contain conventional additives such as chain extenders and / or crosslinking agents, reaction retarders such as acidic substances such as H ₃ PO ₄ surface-active substances such as emulsifiers, foam stabilizers, dyes and fillers, etc. contain.

The foam material can be produced, for example, by a one-step process, a prepolymer process or a semi-prepolymer process and then processed further. With regard to the above-mentioned production process of the TPU (thermoplastic polyurethane) foam body used here, reference is made to US Pat. No. 2,764,565 and the Plastics Manual, Volume VII, edited by Vieweg and Höchtlen, Carl-Hansa-Verlag Munich 1966, e.g. B. on pages 121 to 205. The foam blocks produced with a foam height of about 12 cm are cut for use according to the invention by means of saws, to the desired width and length. The board-like strips cut in this way are placed within the ski shape in accordance with claim 8. They can be brought to a temperature of about 200 ° C. in advance for about 10 minutes, either by application of infrared radiators or by storage in a heating cabinet or

Heating tunnel. The strips heated to this temperature can then immediately be placed in the ski form and pressed within the ski form with the specified pressure of 6-12 bar, possibly up to 15 bar. The pressing time inside the mold is about 5 - 10 minutes at a temperature of 80 to 140 ° C.

Further details of the ski according to the invention and of the method according to the invention for the production of such skis are described in the subclaims.

The production of a ski according to the invention is briefly explained below with the aid of the attached drawing, with FIGS. 1 and 2 schematically showing two different phases of the production process in cross section. Accordingly, a ski core 1, which is approximately trapezoidal in cross section, together with the upper flange 3, lower flange 2, tread 4 and steel edges 5 is placed in a lower mold 11.

A layer of rigid foam that is compressible under pressure and temperature, originally up to about 80% open-pored, is placed over the ski core or upper flange 3. This hard foam layer or strip is previously coated on all sides with an adhesive 13, in particular epoxy adhesive. The same applies to the underside of a cover film made of ABS polyester or the like which has already been preformed in a separate operation. The cover film has the reference number 6. By means of a three-dimensionally effective upper mold 12, the mold cavity 14 of which determines the upper side including the side cheeks of the ski to be produced the cover sheet 6 is pressed under compression of the foam material layer 9 over the ski core 1 under close contact with the upper side and the two long sides of the ski core, the lower and upper molds remaining in the corresponding relative position until a permanent connection between the cover sheet and Ski core is preserved. By means of the upper mold 12, such a high pressure is exerted on the ski core via the cover film that the foam layer arranged between cover film 6 and ski core 1 or top flange 3 is pressed to a thickness which is about 60%, preferably up to 20% of the original Thickness corresponds (see Fig. 2). Furthermore, the foam layer 9 is pressed under a pressure of about 6-12 bar, preferably up to 15 bar, and a temperature of about 80-140 ° C., preferably up to 160 ° C., over a period of about 5 - 20, especially about 10 minutes.

Any voids 10 between the cover film 6 and the two side surfaces of the ski core 1 are filled with the adhesive 13. In any case, practically no foam material 9 escapes into these cavities. Otherwise, the cavities 10 are only very slight or narrow Gaps that can only absorb excess glue 13 anyway. As stated above, a large part of the adhesive penetrates into the open pores of the foam strip 9, so that it is permanently solidified after compression and heat curing.

The cover film 6 is dimensioned such that it extends in a half-shell shape over the upper flange 3 and the two longitudinal side faces 7, 8 of the ski core 1 to just above the tread or up to the side steel edges 5.

The cover film 6 preferably has a thickness of approximately 0.5-1.2 mm, in particular approximately 0.9 mm.

After the hard foam strip 9 has been pressed under pressure and temperature to up to 20% of the original thickness, the filler layer between the cover film and the ski core is practically non-porous. The still existing pores serve to absorb trapped air, so that this no longer has any external effect.

The hard foam strip extends essentially over the entire length of the ski. It can be pressed differently over the length and width of the ski depending on the dimensioning of the ski core 1 and / or the ski shape 11, 12. Also locally different pressings are possible with the formation of surface structures. The rigidity of the ski over its length can also be set within certain limits by different pressing in the longitudinal direction of the ski.

All of the features disclosed in the application documents are claimed as essential to the invention, insofar as they are new or in combination with respect to the prior art.

Claims

Skis, especially alpine or cross-country skiing

1. Ski, in particular alpine or cross-country skiing, consisting of one

Ski core (1); Lower flange (2); - top chord (3); tread (4) arranged below the lower flange with or without side steel edges (5); and an upper cover film (6) which is half-shell-shaped over the upper flange (3) and the two longitudinal side surfaces (7, 8) of the ski core (1) to just above the tread or to the side steel edges (5) extends, with εich between the cover film (6) and the ski core (1) thermoplastic filling material, characterized in that an originally up to 80% open-pored rigid polyurethane foam (TPU) is used as the thermoplastic filling material (9) is permanently compressible or compressible under a pressure of 6 to 12 bar and a temperature of 80-140 ° C in the pressure direction.

2. Ski according to claim 1, characterized in that the filling material (9) extends essentially only over the upper side and just above the two upper side edges of the ski body, and that in the remaining cavities (10) only by one between the ski core (1) and the top cover film (6) applied adhesive (13), in particular epoxy adhesive, are filled.

3. Ski according to claim 1 or 2, so that the upper cover film (6) consists of ABS, polyester or the like and has a thickness of approximately 0.5-1.2 mm, in particular approximately 0.9 mm.

4. Ski according to one of claims 1-3, characterized in that the filling material (9) is pressed under pressure and temperature to at least about 60%, in particular up to 20% of its original thickness, so that an almost non-porous filling layer between top cover film (6) and ski core (1) or top flange (3) is obtained.

5. Ski according to claim 4, characterized in that the filling material (9) is pressed differently over the length and width of the ski, in particular is also pressed differently locally, with the appropriate formation of surface structures and, if appropriate, under appropriate conditions Setting the stiffness of the ski along its length.

6. Ski according to one of claims 1-5, characterized in that daε filling material (9) as a hard foam body or strip iεt used, which or the all-sided before the Verpreεεung with adhesive (13), in particular epoxy adhesive is that when pressed into the open pores of the

Foam strip (9) penetrates, so that the pressed foam strip passes through with adhesive and is solidified accordingly while simultaneously connecting it to the ski core (1) or to the upper flange (3) on the one hand and on the upper cover film (6) on the other. 6524] 2

7. Ski according to claim 6, characterized in that the adhesive (13) is applied in an amount of approximately 80-200 g / m ² .

8. A method for producing a ski according to one of claims 1-7, characterized in that a) a cover sheet made of ABS, polyester or the like is brought into a shape approximately corresponding to the final shape in a separate operation, b) the Ski core including top flange, bottom flange, tread and possibly steel edges is placed in a bottom mold (11); c) a prefabricated over the ski core or top chord

Layer of pressure-resistant and temperature-sensitive, originally up to 80% open-pore hard foam is placed in order to then place the cover film over the hard plastic layer after glue, in particular epoxy adhesive, has been placed on the hard foam layer, in particular the top layer thereof. and underside was applied; and that then d) by means of a three-dimensionally effective upper mold (12) the cover film is pressed onto the ski core with compression of the foam material layer with tight contact on the upper side and the two longitudinal sides of the ski core, the lower and upper mold in the corresponding relative position for so long persist until a permanent connection between the top

Cover film and ski core and an inner consolidation of the hard foam layer is obtained.

9. The method according to claim 8, characterized in that mit¬ means of the upper mold (12) such a high pressure over the Cover film is exerted on the ski core that the hard foam layer arranged between the cover film and ski core is pressed to a thickness which corresponds to approximately 60%, preferably up to 20% of the original thickness.

10. The method according to claim 8 or 9, characterized in that the pressing of the hard foam layer takes place under a pressure of about 6 - 12 bar and a temperature of about 80 - 140 ° C, over a period of about 5 - 20 minutes .