EP2661975B1 - Ski shoe with removable sole of the shell - Google Patents

Description

The present invention relates to a ski boot comprising a shell, an inner liner and a bottom sole of removable shell. Typically, shoes of this type also include an upper part, the collar, and an outsole on said shell, this outsole being intended to cooperate with a binding on a ski and the collar being mounted on the hull bottom pivotally so as to allow relative rotation between the collar and the shell bottom.

This type of ski boots is conventionally used in the field of downhill skiing, ski touring, or in the context of skating type cross-country skiing in that the shoe used has a rigid body. The arrangement of the bottom shell bottom has an important influence on the physical properties, in particular on the thermal insulation, and on the comfort.

The European patent application EP 1 961 322 discloses a ski boot having a hollow rigid inner shell provided with an outer sole, an inner elastic liner, and a support for the inner liner, which support acts as a bottom shell sole and is adapted to be fitted into the base shell so as to be located close to, or against the outsole. The support is made in two parts, a very rigid part, for example metal, and a less rigid part, for example made of a thermoplastic material, the objective being indeed to improve the transmission of force between the skier, respectively the shoe, and skiing. The physical dimensions of the two parts are fixed, and the rigid part is relatively heavy.

International patent application WO 2005/070245 discloses a removable sole allowing adaptation of the interior volume of a ski boot. For this purpose, the removable sole has ribs of different height on its upper part and on its lower part, the ribs of the removable soleplate being able to cooperate with ribs arranged on the upper surface of the insole of the shell of the shoe. ski. Turning the sole removable, the interior volume of the latter can be varied. To accomplish this function, the removable sole must be made of a very rigid material, which, on the one hand, deteriorates a good transmission of force between the shoe and the ski. On the other hand, the ribs function as thermal bridges that cool the foot and therefore have a detrimental effect on the skier's comfort.

The European patent application EP 1487292 discloses a sports shoe, in particular a ski boot, with a rigid shell and a sole consisting of two parts, namely a rigid outer part and an inner part. The outer part and the inner part can be assembled and fixed to one another by means of through screws. If this solution allows for a flexible sole, it has the significant disadvantage that this combined sole is quite heavy.

In sum, the solutions of the prior art currently known do not allow, to the knowledge of the applicant, to bring together all the characteristics desirable for a ski boot, in particular at the level of the mechanical support, the transmission of forces, the thermal insulation as well as, in general, with regard to the comfort to wear the ski boot that follows.

The object of the present invention is therefore to overcome the drawbacks of known ski boots and to achieve the aforementioned advantages, in particular to provide skiers with a ski boot whose interior volume of the shell can be adapted and presenting a comfort high for the skier while being robust, light and ensuring good thermal insulation and good transmission of forces to the ski. In addition, the ski boot should be relatively simple to design, so as not to increase the complexity and production costs and to ensure its reliability during use.

For this purpose, the present invention provides a ski boot of the aforementioned type which is distinguished by the features set forth in claim 1 as well as a bottom sole of removable shell adapted for such a ski boot according to claim 9. In particular, such a ski boot, respectively such a bottom shell sole, comprises a heel pad and a metatarsal plate made of a single block in a material density of less than 120 g / l, especially PPE. In addition, the bottom shell sole can be made of different thicknesses and optionally, it can be equipped with ribs.

By these measures, the lower base of removable shell, and therefore the corresponding ski boot, has a particularly low weight and excellent properties in terms of thermal insulation while allowing adaptation of the interior volume of the hull of the ski boot by exchanging the bottom shell sole of a given size by a sole of another size. The bottom shell of the removable shell according to the invention is, in addition, a stable and robust mechanical support for the inner boot having favorable properties in terms of the transmission of forces from the boot to the ski and simultaneously serving as a drainer for water entering from the outside into the ski boot or forming inside due to the perspiration of the skier, especially if it is equipped with ribs and / or has a sufficient thickness. The fact that the bottom shell sole of the ski boot is made in one piece further strengthens the favorable thermal properties which the sole already has due to the choice of its manufacturing material and allows, moreover, a particularly simple manufacturing and economic.

Other features, as well as the corresponding advantages, will emerge from the dependent claims, as well as from the description which sets forth the invention in more detail.

The accompanying drawings show schematically and by way of example an embodiment of the invention.

The figure 1a shows a schematic perspective view illustrating a ski boot according to the present invention; the figure 1b represents a longitudinal section through the ski boot of the figure 1a .

The figure 2a shows a perspective view of the lower portion of a removable bottom shell sole for the ski boot of the figures 1a and 1b oriented in the assembled state of the ski boot to an outer sole of the shell bottom, and the figure 2b shows a similar perspective view of the upper part of the bottom shell of the removable shell oriented in the assembled state towards the skier's foot; the Figure 2c shows the bottom shell of removable shell in a view from below and the Figures 2d, 2e, 2f, and 2g show different side views, namely seen from the front, back, left and right of the sole.

The invention will now be described in detail with reference to the accompanying drawings illustrating by way of example an embodiment of the invention.

The present invention relates to a ski boot 10 with a rigid shell which comprises a lower part, the bottom of shell 1, and preferably even normally but not necessarily, an upper part, the collar 2. It is a question of preference and as illustrated in the figures, a alpine shoe type "front entrance", but it can also be a ski boot for the practice of cross-country skiing or cross-country skiing provided that the shoe has a substantially rigid shell such as those used for example for the practice of skating.

As illustrated schematically and by way of example in a perspective view at the figure 1a , illustrating in more detail the ski boot 10 with the shell bottom 1, the collar 2, and an inner boot 4, said bottom shell 1 comprises an outer sole 1.1 formed integrally with said shell bottom 1 and intended to cooperate with a not shown ski binding. Said collar 2 is adapted to be mounted on the shell bottom 1 pivotally, in order to allow a relative rotation of a certain angular amplitude between the collar 2 and the bottom shell 1 giving the user the opportunity to make movements during the practice of the skiing or even walking without being hindered by the rigid shell and while having good hold in the ski boot 10. The bottom shell 1 and the collar 2 comprise closure elements 6, such as hooks, buckles or straps, allowing the user to tighten the ski boot 10 around his foot. To allow this rotation, the ski boot 10 further comprises hinge means 3 for performing said relative rotation between the collar 2 and the shell bottom 1. The collar 2, the inner boot 4, the means articulation 3 and the closing elements 6 are not important for the present invention, they will not be described in more detail later and may be constituted by any means known to those skilled in the art.

The figure 1b shows a longitudinal section of the ski boot 10 according to the figure 1a . It is clearly visible on this figure 1b that a bottom shell of removable shell 5 according to the present invention can be inserted by the user, the opening at the top of the collar 2 of the ski boot 10, respectively in general by the opening at the top of the ski, between the inner liner 4 and the outer sole 1.1 of the shell 1, before the inner liner 4 is placed inside the shell 1. This bottom shell of the removable shell 5 has a heel pad 5.1 and a metatarsal plate 5.2 , these parts 5.1, 5.2 corresponding to the respective parts of the foot of the skier. The heel pad 5.1 and the metatarsal plate are made of a single block in the same material.

In particular, the heel pad 5.1 and the metatarsal plate 5.2 are made of a material with a density of less than 120 g / l. It is particularly advantageous to manufacture the bottom shell of removable shell 5 EPP Expanded Polypropylene. The selected material preferably has a hardness greater than 65 Shore A, and / or a weight so that the sole 5 has, for a size of 26/27, a weight less than 25g.

The choice of the preferred material for the manufacture of the heel pad and the metatarsal plate will be clearer in view of the features illustrated in the table below. This table mentions, by way of comparison, the values of important parameters obtained by the applicant for a low shell sole made of monobloc, on the one hand, and on the other hand, either of injected PP (polypropylene) or PU (polyurethane) cast. Material of manufacture Density Weight (size 26/27) Hardness Duration of toe insulation machinability Cost per piece Injected PP outsole 900 g / l 81gr ≈ 90shA Ref. (TR) difficult Index 100 PU molded sole 200 g / l 40gr ≈ 70-80shA TR + 29% easy 400 index PPE sole 100 g / l 18gr ≈ 70-80shA TR + 39% easy Index 180

As shown in the second column of this table, the injected PP used to make the comparison shown in the table has a density of about 900 g / l, this value being typical for this material, the PU cast used has a density of about to 200 g / l, this value being likewise typical for this material, whereas the EPP used to make a bottom shell sole 5 according to the present invention has a density of less than 120 g / l, in the example shown in the table. of 100 g / l.

It emerges from the third column of this table, that this has the consequence that the bottom shell sole 5 according to the present invention made in PPE monoblock has a weight by a factor of about 2, respectively about 4, compared to a corresponding sole made of cast PU, injected PP respectively, without the sole 5 does not lose strength.

This last aspect is also illustrated by the fourth column of the table above mentioning the hardness of the different materials compared. As explained above, it follows that an injected PP soleplate is much harder and inflexible than a molded PU soleplate or PPE, these two materials having similar values in terms of hardness. Hardness also plays a role in the transmission of forces from the skier's foot to the ski, via the ski boot 10 and therefore the bottom shell sole 5, as explained in the introduction.

The fifth column of the table above attempts to provide a comparison between bottom shell flanges made of the aforementioned materials at the thermal insulation obtained. Taking as a reference a sole made of injected PP, the table shows that the toes of a skier having a ski boot equipped with a cast PU sole will put about 30% more time to cool, that is to say that PP is more insulating than PU. Finally, the EPP is even more insulating because the toes of a skier with a ski boot equipped with a PPE sole will even put about 40% more time to cool. The same measurements can be repeated at the metatarsal or even the ankle and show similar results, namely an improvement of the thermal insulation by an EPPE soleplate of about 24% compared to an injected PP insole, about 39%, respectively, with respect to a PU sole cast at the metatarsal level and an improvement of the thermal insulation by a soleplate 5 made of PPE of about 12% compared with an injected PP soleplate as well as a PU sole cast at the ankle. The average of these three regions results in an improvement of the thermal insulation by a sole made of monoblock of PPE according to the present invention of about 20% to 25%, these values obviously also depend on the thickness of the sole used for comparison. In any case, the thermal insulation of a sole 5 made of a piece of EPP according to the present invention is much better compared to the other types of soles mentioned above.

Finally, it emerges from the sixth column of this table relating to the machinability of the material used for the base plate of the shell that, in principle, the EPP used for the sole 5 according to the present invention as well as the PU cast are enough materials. easy to rework, if necessary, for example by strawberries or using a sander, while injected PP is a material that is difficult to rework. This aspect obviously plays a role during production, but especially to allow an adaptation of the interior volume of the shoe to the shape of the user's foot.

Also for this reason, but also because of the process used to produce the corresponding sole and on the basis of the price of the base material, the seventh column of the table above shows that the bottom shell sole 5 according to the The present invention manufactured in EPP represents a very good compromise in terms of production costs. Indeed, as shown by the other columns of the table, for technical characteristics much better than an insole injected PP and at least equivalent to a molded PU sole, the production price of a sole 5 according to the present invention, made of PEP monobloc, it is much closer to the relatively low production costs of an injected PP outsole than to the relatively high production costs of a molded PU sole. The last column of the table shows this aspect by comparing the cost of a sole according to the invention and that of a cast PU sole at the cost of manufacturing a sole PP (index 100). We see that a molded PU sole is 4 times more expensive than a sole PP, while the sole according to the invention is only 1.8 times more expensive to manufacture.

Having discussed the characteristics and advantages of the material chosen for the low shell base 5 used for a ski boot 10 according to the present invention, it should be noted that at the level of the bottom shell structure 5, it is preferably that the heel pad 5.1 has a thickness 5.1.1 greater than 10 mm, preferably greater than 15 mm, and that the metatarsal plate 5.2 has a thickness 5.2.1 less than the thickness 5.1.1 of the heel pad 5., but this having a thickness 5.2.1 greater than 4 mm, preferably greater than 5 mm. These dimensions of the removable shell bottom sole 5 make it possible to vary the volume of the interior of the ski boot 10 enough by placing therein a soleplate 5 of minimum thickness, of maximum thickness, or of an intermediate thickness located between the values indicated above, while maintaining the comfort of wearing the shoe 10.

In a preferred embodiment of the ski boot 10, respectively the bottom shell of removable shell 5 according to the present invention, the sole has retaining ribs 5.3 between the heel pad and the metatarsal plate, on its lower side intended to be placed on the outsole 1.1. These retaining ribs 5.3 make it possible to make the bottom sole of the removable shell 5 according to the invention more robust and mechanically stable. This is important because the sole 5 serves as a mechanical support for the inner boot 4 and should have favorable properties in terms of the transmission of forces from the boot to the ski. In addition, these ribs 5.3 simultaneously serve as a drainer for water entering from the outside into the ski boot in the form of snow or rain or forming in its interior due to the perspiration of the skier. This effect is reinforced by increasing the thickness 5.1.1, 5.2.1 that the sole 5 has.

Furthermore, the bottom shell of the removable shell 5 according to the present invention may also comprise projecting parts 5.4 serving to position the sole well on the outer sole 1.1 of the shell bottom 1 inside the ski boot 10, this in cooperation with corresponding grooves not shown in the figures that comprises the bottom 1.2 of the bottom shell 1. Thus, the accuracy of the positioning of the sole 5 inside the ski boot 10 and the stability of this position are improved , as well as the rigidity of the removable bottom shell assembly 5 and outer sole 1.1 of the shell bottom 1, this which consequently improves the transmission of forces from the boot to the ski.

In another embodiment of the ski boot 10 according to the present invention, the bottom 1.2 of the bottom shell 1 has support ribs, also not shown in the figures, which are preferably arranged in a complementary manner to the ribs. support 5.3 on the bottom shell of removable shell 5, so that the accuracy of the relative positioning between these two parts and the rigidity of this set can be further improved. Similarly, the fact that the sole of the ski boot 10 is indeed composed of two parts, a sole 1.1 rigidly connected to the bottom shell 1 of the shoe 10 and a removable sole 5 just placed on the first and becomes less less sensitive for a user of the ski boot 10. By all these measures, the comfort for the user is thus improved.

The different parts of the removable sole 5 which are mentioned above are more visible on the Figures 2a and 2b showing perspective views of the lower portion of the bottom shell of the removable shell 5 oriented in the assembled state of the ski boot 10 towards the outer sole 1.1 of the shell bottom 1, respectively of the upper part of the bottom sole of the removable shell 5 oriented in the assembled state towards the foot of the skier, as well as the Figures 2c shows the bottom shell of removable shell in a view from below and to Figures 2d, 2e, 2f, and 2g showing different side views.

In view of the aforementioned explanations relating to the structure and the material of the ski boot, respectively of the bottom shell of the removable shell according to the present invention, it is obvious that such a ski boot and removable shell bottom sole provide many benefits and achieve the goals set out in the introduction. In particular, a ski boot combined with a bottom shell of removable shell according to the present invention offers the possibility of varying the interior volume of the ski boot, excellent thermal insulation, good transmission of forces, robustness and proper stability, while ensuring high comfort for the wearer of the ski boot.

Claims (9)

1. Ski boot (10) having a shell (1), an inner boot (4) and a removable lower-shell sole (5), said lower-shell sole (5) having a heel block (5.1) and a metatarsal plate (5.2), where the heel block (5.1) and the metatarsal plate (5.2) are formed in one piece from expanded polypropylene (EPP) having a density of less than 120 g/l, which has a hardness greater than 65 Shore A, and where the heel block (5.1) has a thickness (5.1.1) greater than 10 mm, preferably greater than 15 mm.
2. Ski boot (10) according to the preceding claim, characterized in that the metatarsal plate (5.2) has a thickness (5.2.1) less than the thickness (5.1.1) of the heel block (5.1), in particular a thickness (5.2.1) greater than 4 mm, preferably greater than 5 mm.
3. Ski boot (10) according to one of the preceding claims, characterized in that the weight of the sole (5) for a size 26/27 is less than 25 g.
4. Ski boot (10) according to one of the preceding claims, characterized in that the sole (5) has supporting ribs (5.3) between the heel block (5.1) and the metatarsal plate (5.2).
5. Ski boot (10) according to one of the preceding claims, characterized in that the bottom (1.2) of the shell (1) has support ribs.
6. Removable lower-shell sole (5) for a ski boot (10) according to one of the preceding claims, said removable lower-shell sole (5) having a heel block (5.1) and a metatarsal plate (5.2), where the heel block (5.1) and the metatarsal plate (5.2) are formed in one piece from expanded polypropylene (EPP) having a density less than 120 g/l and a hardness greater than 65 Shore A, and where the heel block (5.1) has a thickness (5.1.1) greater than 10 mm, preferably greater than 15 mm.
7. Removable lower-shell sole (5) according to Claim 6, characterized in that the metatarsal plate (5.2) has a thickness (5.2.1) less than the thickness (5.1.1) of the heel block (5.1), in particular a thickness (5.2.1) greater than 4 mm, preferably greater than 5 mm.
8. Removable lower-shell sole (5) according to one of Claims 6 and 7, characterized in that the weight of the sole (5) for a size 26/27 is less than 25 g.
9. Removable lower-shell sole (5) according to one of Claims 6 to 8, characterized in that the sole (5) has supporting ribs (5.3) between the heel block (5.1) and the metatarsal plate (5.2).

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