EP1745826B1 - Process for machining running bases of wintersport apparatuses - Google Patents

Abstract

The method involves moving a machining tool (5) over running surface (9) of a track blank (20), and pressing with preset force on the track blank to deform the track black to form groove structure with even depth. The tool has diamond tip (1) with radius (R) of 0.02mm and cone angle of 60[deg]. Independent claims are included for the following: (1) winter sports appliance; and (2) apparatus for producing tracks of winter sports appliance.

Description

The invention relates to a method for processing treads of winter sports equipment, such as skis or snowboards, in which a pad blank is subjected to a machining operation to obtain a predetermined surface microstructure, which improves the lubricity, and a corresponding device for machining pads of winter sports equipment.

The sliding of a winter sports equipment, such as a ski on snow, represents a friction case of a special kind. This is because the individual friction partners, such as covering, snow and intervening water film are difficult to define and the geometric conditions are difficult to describe and variable , It is known that the frictional resistance under circumstances such as in skis, but also in other circumstances, such as in boats or aircraft may possibly be favorably influenced by targeted roughening of the surface of the object in question. One reason for the improved sliding properties of rough surfaces of skis is in the fact that suction effects are reduced or avoided at higher speeds.

As a material for the production of Schibelägen has largely enforced polyethylene. Particular advantages of polyethylene, especially with medium and high molecular weight are the good wear and sliding behavior of high toughness and at the same time excellent chemical resistance. These advantages, in particular the abrasion resistance, increase with increasing molecular weight, so that ultrahigh-molecular weight polyethylene with a molecular weight of several million is used, in particular for critical applications, such as racing. However, the production and processing of ultrahigh molecular weight polyethylene linings is difficult because this material is not extrudable and extremely difficult to deform.

In practice, the surface structures required to improve the sliding properties are mostly applied by grinding operations, but this entails various disadvantages. First, it is due to unavoidable thickness tolerances the coating production hardly possible to achieve a uniform surface roughness, since the thickness tolerances are greater than the depth of the structure to be produced. In this way, it is unavoidable that the surface properties, such as the roughness, depend on the respective locally present thickness variations of the lining blank and are thus uneven and not reproducible. Another disadvantage of grinding methods is that the inevitable local heating of the lining surface undesirable chemical changes occur that worsen the sliding properties. In addition, there may be chemical interactions between the abrasive material and the material of the lining, which represents a further impairment.

The FR 2 112 645 A discloses a device for forming grooves in a plastic film similar to that used for scoring cardboard. This plastic film scoring apparatus has a rotating roller having a smooth and homogeneous surface, the plastic film to be scored coming in contact with it along a generatrix of the same. On the same generatrix, pressure is applied at one point or at several points thereof through the plastic film which is controllable by means of scoring members such as cutting wheels, balls or a grooved or ribbed roller. The at least one scoring member is designed to support itself along the generatrix of the roller and to exert here a controllable pressure adapted to the desired scoring depth on the plastic film guided between the scoring member and the opposing roller. A method and an apparatus for producing a surface microstructure, which improves the slipperiness of the tread of winter sports equipment, this document is not apparent.

From the WO 03/061783 It is known that the structure of a Schibelag can be divided into a macrostructure and a microstructure. The macrostructure is defined as structures with a depth> 20 μm. The microstructures are smaller structures. In this document, it is correctly stated that in practice the structuring is produced by grinding the surface, as described above, but only the macrostructure can be produced reproducibly. In particular, the microstructure is dependent on a large number of parameters which can not be influenced directly, so that even under identical production conditions, there are great differences in the sliding behavior. To avoid these disadvantages is in the WO 03/061783 suggested to pattern a coating by an embossing process in which an embossing roll is rolled over the coating to produce a microstructure.

However, such embossing methods encounter increasing difficulties with increasing molecular weight of the material of the covering, since plastic deformation is only possible to a very limited extent due to the reduced flow properties. In addition, the non-uniformities already described above occur as a result of the thickness tolerance, since the local pressure of the embossing tool on the lining surface is greatly influenced by the variations in thickness of the lining itself. Due to these facts, it is hardly possible to produce reproducible surface structures, especially in the case of high molecular weight coatings, even with such a process. Such embossing is also in the DE 102 43 310 A disclosed. In addition, the describes EP 1 415 686 A a modified embossing method, which however can not eliminate the above disadvantages.

The DE 40 13 901 A describes a method for profiling the running surfaces of skis. Scaled structures are primarily produced in the area of the bond, which should improve the climbing behavior. Such structures must have typical orders of magnitude above the macrostructures as described above. In this case, a machining tool is pushed into the tread in shock-striking or chisel-like motion. However, it is not known to use such or a similar method for producing microstructures.

Object of the present invention is to provide a method by which the above disadvantages are avoided and with which it is possible to produce a well-defined and reproducible surface structure of a covering for a winter sports equipment. In this case, the greatest possible degrees of freedom in the geometric design of the surface structure should be possible. The process should furthermore not cause any influence on the chemical composition and properties.

Another object of the present invention is to provide a device for producing such a coating.

According to the invention, these objects are achieved by a method characterized in that the tool comprises at least one tool tip which is moved in sliding movement over a running surface of the lining blank and is pressed onto the lining blank with a predetermined force to form grooves, wherein the the plastic deformation comprehensive machining operation is performed on a coordinate table. The microstructure refers to depressions or protrusions with a typical height dimension of less than 0.02 mm. It has been found that by a plastic deformation, which is brought about by a relative movement of the tool with respect to the surface of the covering or lining blank to be machined, a surface structure can be created, which is characterized by a local material displacement. An essential aspect of the present invention is that the production of the surface structure is force-controlled, that is, the force with which a tool is pressed onto the running surface is largely independent of local thickness variations due to production tolerances or the like. In this way, the disadvantages described above can be avoided and in particular a uniform and completely reproducible surface structure without deterioration of the chemical properties is achieved. The method according to the invention provides that, during the deformation of the lining blank, at least one tool tip is guided in sliding movement over the running surface of the lining blank. Such a method is referred to in another context as guilloche. It is an engraving process that originated in metalworking and was used a long time ago for the production of high-quality watches. According to the invention, the machining takes place on a coordinate table, which is a working device in which a tool can be moved over the workpiece in the longitudinal and transverse directions, as in the case of a plotter.

A diamond cone is particularly preferably used for such a method, since due to the high hardness an extreme abrasion resistance is given and due to the inert material no chemical influences on the surface are to be feared.

It is particularly advantageous if the tool tip has a radius of about 0.02 mm. In this way, microstructures of optimum size can be produced.

Particularly favorable sliding properties are achieved if the tool is moved at least in sections at a predetermined angle to the longitudinal direction of the lining blank. If it is a right angle, the grooves produced run transversely to the direction of travel, which offers advantages in certain snow conditions. But it is also possible to provide wave pattern, both variants have advantages over the known and largely procedural arrangement of longitudinal grooves on the lining surface.

A particularly advantageous variant of the method according to the invention is characterized in that the machining process comprising the plastic deformation takes place on the lining blank prior to application to the winter sports device. Such a procedure includes several advantages. On the one hand, it is possible to work on a flat base which is not curved and prestressed in the longitudinal direction like an assembled ski. Another advantage of this variant of the method is that no consideration for steel edges has to be taken during machining of the coverings. Before or after processing, the lining blank is cut precisely and inserted into the recess between the steel edges.

With the method according to the invention winter sports equipment can be created with a tread, preferably made of polyethylene, the tread has a predetermined structure.

In such a winter sports equipment, the surface structure of the tread is made by plastic deformation. It has been found that such winter sports equipment, especially in critical applications, such as in racing, ie at very high speeds, and using high-quality materials such as ultra-high molecular weight polyethylene, have particular advantages.

In this context, it is particularly favorable for the sliding properties if the structure is designed as a groove structure with a uniform depth. It has also been found to be favorable when the surface structure is composed of predetermined geometric patterns. Chemical changes of the coating surface can thereby be avoided that the surface structure is made by chipless machining.

Furthermore, the invention relates to a device for the production of coverings of winter sports equipment with a tool guide for guiding a tool that applies a predetermined surface structure on the tread of the covering comprising a surface microstructure, which improves the lubricity, wherein the tool for chipless production the surface microstructure is adapted to cause a plastic deformation of the tread. According to the embodiment of the invention, such a device is characterized in that the tool has at least one tool tip for producing a groove having a predetermined profile and can be pressed with a predetermined force on the running surface of the lining blank, wherein a coordinate table is arranged for moving the tool.

The processing performance can be improved in a particularly favored manner, that several tools for simultaneous processing of the tread of the lining blank are provided on the tool guide. In this way it is possible, for example, simultaneously to machine a slide day over its entire width, similar to conventional methods, without abandoning the advantages described above. It is particularly advantageous in this context, when the individual tools are spring-mounted independently. This ensures that each individual tool can optimally adapt to the respective local variations in thickness. Alternatively, however, other solutions, such as a hydraulic storage of the individual tools are possible. An optimal adaptation of the surface structure to the respective required sliding and driving properties of the winter sports equipment can be carried out in a particularly preferred manner by the fact that the tool guide has a control for the production of predetermined patterns on the running surface of the lining blank.

As a result, the present invention will be explained in more detail with reference to the embodiments illustrated in FIGS.

Fig. 1

schematisch ein Detail eines einzelnen Werkzeuges in einer Ansicht;

Fig. 2

ein Vielfachwerkzeug;

Fig. 3 bis 6

verschiedene Ausführungsvarianten der Bearbeitung des Belages; und

Fig. 7

ein Detail von Fig. 1.

Show it:

Fig. 1

schematically a detail of a single tool in a view;

Fig. 2

a multiple tool;

Fig. 3 to 6

various embodiments of the processing of the coating; and

Fig. 7

a detail of Fig. 1.

The tool of FIG. 1 is an engraving diamond 5 having a shank diameter D of, for example, 3 mm, a cone angle α of 60 ° and a radius R of the diamond tip 1 of 0.02 mm. The pad blank is indicated by 20.

Fig. 2 shows a multiple tool, in which side by side a plurality of diamond pins 5 are displaced in the longitudinal direction and each biased by a spring 6. Behind the pins 5 of the first row more pins are arranged on the gap in order to produce a larger groove density can.

Fig. 3 shows schematically a portion of a ski 7 with exaggerated sidecut. The steel edges 8 delimit the running surface 9. A plurality of grooves 11 is arranged at an angle β to the longitudinal axis 10a, which angle β in the given example is about 45 °.

In the embodiment of Fig. 4, the grooves 11 are arranged substantially in the longitudinal direction and wavy. The embodiment of Fig. 5 corresponds substantially to that of Fig. 3 with the difference that the grooves 11 are arranged transversely to the longitudinal axis 10a.

In the embodiment of Fig. 6, the grooves 11 are in the form of triangular structures which are distributed over gaps on the pad 9.

Fig. 7 shows the surface structure of Fig. 1 in detail. A depression 31 is bounded by two elevations 30, which are produced by material displacement. The vertical dimension of the recess 31 is designated h ₁ and is for example 0.015 mm. The vertical dimension of the elevations 31 is designated by h ₂ and is about 0.01 mm. Thus, the total height H is about 0.025 mm. Since both h ₁ and h _{2 are} smaller than 0.02 mm, this is a microstructure in the sense of the invention.

Claims (15)

1. Process of machining running surfaces (9) of winter sports apparatuses, such as skis or snowboards, whereby a track blank (20) is subjected to a machining process which does not involve removing material in order to produce a predefined surface micro-structure which improves gliding ability, and the machining process for producing the surface micro-structure involves inducing a plastic deformation by means of a tool (5), characterised in that the tool (5) has at least one tool tip (1) which is moved in a sliding movement across a running surface (9) of the track blank (20) and pressed onto the track blank (20) with a predefined force in order to form grooves (11), and the machining process inducing the plastic deformation is run on a co-ordinate table.
2. Method as claimed in claim 1, characterised in that the tool tip is a diamond cone (1).
3. Method as claimed claim 2, characterised in that the tool tip has a radius of approximately 0.02 mm and the pressing force is selected so that the penetration depth of the tool tip is less than 0.02 mm.
4. Method as claimed in one of claims 1 to 3, characterised in that the machining operation is performed by means of a tool (5) which is resiliently mounted and is thus pressed onto the running surface (9) of the track blank (20).
5. Method as claimed in one of claims 1 to 4, characterised in that the tool (5) is moved at a predefined angle (β) with respect to the longitudinal axis of the track blank (20) across at least certain portions.
6. Method as claimed in one of claims 1 to 4, characterised in that the tool (5) is guided across the track blank (20) in wave-shaped movements.
7. Method as claimed in one of claims 1 to 6, characterised in that the machining process on the track blank (20) inducing the plastic deformation takes place before the running surface (9) is applied to the winter sport apparatus.
8. Device for producing tracks for winter sport apparatuses with a tool guide for guiding a tool (5), which applies a predefined surface structure to the running surface (9) of the track, comprising a surface micro-structure which improves gliding ability, and the tool (5) for providing the surface micro-structure without removing material is designed to cause a plastic deformation of the running surface (9), characterised in that the tool (5) has at least one tool tip (1) for producing a groove (11) with a predefined profile and can be pressed onto the running surface (9) of the track blank (20) with a predefined force, and a co-ordinate table is used for moving the tool (5).
9. Device as claimed in claim 8, characterised in that the tool tip (1) is made from diamond.
10. Device as claimed in claim 9, characterised in that the tool tip has a radius of approximately 0.02 mm.
11. Device as claimed in one of claims 8 to 10, characterised in that the tool tip has a cone angle (α) of approximately 60°.
12. Device as claimed in one of claims 8 to 11, characterised in that the tool (5) is resiliently mounted in the tool guide.
13. Device as claimed in one of claims 8 to 12, characterised in that several tools (5) are provided on the tool guide for simultaneously machining the running surface (9) of the track blank (20).
14. Device as claimed in claim 13, characterised in that the individual tools (5) are resiliently mounted separately from one another.
15. Device as claimed in one of claims 8 to 14, characterised in that the tool guide has a control system for producing predefined patterns on the running surface (9) of the track blank (20).

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