The present invention relates to a cross-country ski boot and a cross-country ski binding system.

It is known to attach a ski boot to a ski binding by means of a pin mounted to the front section of the ski boot, cf. the well-known binding standards NNN®, BC®, Xplore®, and SNS®. What characterizes these systems is that the pin has a given width (which varies slightly depending on the standard) and is mounted so far forward on the sole that the pivot point of the binding system is located well forward of the transition between the metatarsals and phalanges of the foot. It is between these bones in the foot, inter alia, much of the bending of the foot takes place during cross-country skiing, walking, running, jumping, etc. The conventional mounting point of said pins is a trade-off between several factors, such as the distance between the sole of the foot and the ski/binding, the maximum achievable included angle between the ski boot and ski/binding, sufficient anchoring, among other factors. In general, it is desirable to have the foot as close as possible to the ski, i.e., that the distance between the sole of the foot and the ski/binding is as small as possible, and that the included angle between the ski boot and ski/binding is as large as possible and at least greater than a given minimum angle. In addition, it is desirable to have the pivot point of the binding system below -or at least as close as possible to - the transition between the metatarsals and phalanges of the foot, so that the biomechanical movement pattern of the body and generation of power can be optimised.

Attempts have been made to move the pivot point of the binding system further back, see EP3935984A1, for example. In this patent, it is proposed to use a cleat having lateral, protruding pins mounted approximately below the transition between the metatarsals and phalanges of the foot. Such a design allows the biomechanical movement pattern of the body and generation of power to be significantly improved, while it is still possible to reduce the distance between the sole of the foot and the ski/binding to a very acceptable minimum. As compared to the above-mentioned conventional binding standards, a number of advantages are thereby achieved in addition to those already mentioned. For example, the rigidity of the ski boot can be increased significantly (both the bending and torsional stiffness, albeit to different degrees for the different cross-country skiing styles: for the skate style, adequate bending and torsional stiffness are both important, whereas for the classic style the same amount of bending and torsional stiffness is not desirable, even though it is important that the ski boot is able bend and twist in a proper manner, which can be better controlled when the pivot point is positioned approximately below the transition between the metatarsals and phalanges of the foot.)

However, the price paid for moving the pivot point of the binding system further back is that the included angle between the ski boot and ski/binding becomes smaller and sometimes too small. This has several drawbacks. On the one hand, an included angle that is too small may affect the movement pattern of the skier by limiting the range of motion, which is clearly not desirable or acceptable. This would affect the skier's ability to convert power generated by the body into forward momentum in the ski track. This could affect different skiers differently and possibly the most mobile/flexible skiers the most. Moreover, an included angle that is too small also poses a safety risk for both the equipment and skier. The forces from a kick-off, slip or fall can be very large, and the geometry of the binding system could potentially result in the creation of large rocker arm/clamping forces between the tip of the ski boot and the binding/ski. Such forces can be transferred through the pivot point or towards the binding/ski in such a way that the equipment can break. In addition, the forces exerted on the shins and/or other parts of the lower body/back of the skier can lead to injury of the skier. Also, if the equipment breaks on a trip far away from people, this in itself could put the skier at risk.

Therefore, the objective of the present invention is to overcome at least one of the above-mentioned disadvantages.

According to the invention, a cross-country ski boot and a cross-country ski binding system according to the independent claims 1 and 9 are provided. Further alternative or advantageous embodiments of the invention are set forth in the dependent claims.

In the following, a detailed description of the invention is given with reference to the drawings, in which:

Fig. 1 shows a cross-country ski binding,

Fig. 2 shows the outsole of a boot attached to a cross-country ski binding,

Figs. 3a and 3b show a boot outsole from different angles,

Fig. 4 shows a sketch of a foot,

Fig. 5 shows a cross-country ski binding system in which the boot outsole is in a neutral position,

Fig. 6 shows a cross-country ski binding system in which the initial included angle of the system has been reached,

Fig. 7 shows a cross-country ski binding system in which the boot outsole is flexed further, and the reserve included angle has been reached,

Fig. 8 shows one embodiment of the present invention

Figs. 9a-f show different configurations/embodiments of the present invention, and

Fig. 10 shows an embodiment without a flexor. Fig. 2 shows a cross-country ski boot outsole 2 comprising a heel section 3 and a front section 4 having a boot tip 5. Under the front section 4, a cleat 6 (not seen) having lateral, protruding pins 7 (barely seen) is shown mounted forward of the transition between the metatarsals and phalanges of the foot. This point or area is denoted as BG in the drawing. Cleat 6 fits into the binding 8 comprising a flexor 9 in that pins 7 are secured in the complementary crib 10, ref. fig. 1.

It should be understood that the cleat solution itself may vary and that alternative solutions exist. It should also be understood that what is referred to as a cleat 6 may also be integrated into the outsole, that is, it does not need to be releasably attached. What is referred to as a cleat 6 may be provided with various types of attachment mechanisms, not just the protruding pins 7 shown herein. The pins may have a different configuration, may be configured as a conventional NNN pin, or may consist of a rotatable or slidable locking plate.

According to the present invention, the part of boot tip 5 located forward of cleat 6 is designed to be less rigid so as to yield if the initial included angle p of the binding system is approached. In this manner, a reserve included angle 0 is obtained. When ski boot 1 is neutrally positioned in binding 8, it will have a neutral included angle a. The above angles are shown in Figs. 5-7 and will be discussed in more detail later.

The part of boot tip 5 located forward of cleat 6 deflects or bends along or in front of a line L.

It might seem obvious that a front section of a boot or boot tip is less rigid than the rest of the boot sole, but this is not the case with this type of ski boot. One of the advantages of using a cleat 6 like the one taught in EP3935984A1, for example, is that the ski boot 1 -and thus also the boot sole 2- can be made significantly more rigid than if the pivot point 11 of the binding system, in the conventional manner, is located further forward on boot tip 5. With the conventional solution, one is largely dependent on making the boot tip more rigid in order to allow the pin to be sufficiently secured in the plastic material of the sole, and to make sure the front section of the ski boot bends in a biomechanically satisfactory way, which requires that the front section of the ski boot is the most bendable in the transition between the metatarsals and phalanges of the foot. In a conventional solution, this is also necessary in order to partially compensate for the actually unfavourable placement of a conventional pin (the conventional pin - and hence also the pivot point - is located too far forward).

When the pivot point is placed in a more favourable location, i.e., closer to the transition between the metatarsals and phalanges of the foot, then, as mentioned, new problems are introduced. One of these problems is the above-mentioned limitation of the included angle, which the present invention overcomes. Another issue arising is that boot sole 2 is stiffened by cleat 6 at the exact location where it is normally desired that the boot sole is the most flexible. This may be advantageous when practicing the skate technique as a "clap skate effect" can be obtained, but it may turn out to be disadvantageous when practicing the classic technique, in which a maximum contact and feeling with the surface is preferable, which requires the ski boot and ski boot sole to be very flexible.

It is hence understood that the positioning of the pivot point of a ski boot always involves trade-offs and compromises.

According to the present invention, the boot sole is made less rigid in a region directly in front of cleat 5 - which needs to have a certain extent and considerable stiffness - so that the bending or deflection point of the boot sole is placed in a region which is located significantly further forward than what is common, and which one would normally want to be more rigid (to protect the toes). This moving forward of the bending or deflection point of the boot sole must also take into consideration that the toes can be pinched in an unpleasant or harmful way, which must be taken into consideration when designing the vamp and selecting the bending curve and bending resistance.

Within the reserve included angle 0, the bending resistance can be made progressive, i.e., the resistance increases slightly (or a lot) towards the end of the rotational movement. This progressive bending resistance is produced by the flexor 9, which can be configured so that the bending resistance increases as it is compressed when ski boot 1 is rotated and boot tip 5 is pressed into the flexor 9, cf. Fig. 7. At the same time, or alternatively, the bending resistance of boot tip 5 can be adapted so as to produce a desired bending resistance, either alone or in cooperation with flexor 9. Thus, according to a possible embodiment of the invention, the flexible boot tip 5 may be provided with a resilient member, such as a blade made of metal, carbon fibre or another suitable material, which is configured so that the bending energy is stored during bending and then released when the boot tip is allowed to straighten (cf. Figs. 9d, e). This gives a number of advantages, including:

- the bending or deflection point of the ski sole can be designed so as to not cause any discomfort of the foot and particularly of the toes,

-the boot tip may cooperate with flexor 9 and contribute to the desired progressive bending resistance towards the end of the rotational movement of the ski boot,

- a "springboard effect" can be obtained in which part of the bending energy is returned as a bounce providing a slight addition to the forward momentum.

According to a possible embodiment, cf. Fig. 7, the goal is a total included angle (P + 0) of 38°, for example. Incidentally, this angle corresponds to the included angle of the current conventional solutions and has proven to work well. Fig. 6 shows a possible included angle of 31°, for example, without the boot tip 5 bending. Hence, the bending of the boot tip provides for an additional bending angle 0 of 7°, for example. It should be understood, however, that the distance d off the ski of pivot point 7, the thickness of the binding, the shape of the binding, the shape of the boot sole, etc. will affect both included angles and 0 so that the total included angle + 0 is the result of several design choices.

Figs. 3a and b show two different perspective views of the boot sole 2 and cleat 6. A carbon sole or the like extends from heel section 3 to front section 4 up to and including the point at which cleat 5 is terminated in the forward direction, so that the boot tip 5 can be said to extend from cleat 5 and forward. This transition is marked with a line L in Fig. 3b and forward of this line there is only a soft rubber sole and an even softer boot last.

Fig. 3b shows boot tip 5 from the underside, with this embodiment having grooves arranged in the front that indicate where the sole/boot is flexible. Again, it is important to note that this is in a region located forward of where it is conventional to make the boot flexible.

Fig. 4 shows an outline of a foot. The line BG corresponds to the region forming a transition between the metatarsals and phalanges, i.e., the natural deflection or bending area. Most boots are bendable about line BG as long as the boot is not made to be rigid. Fig. 4 also shows that the point of rotation RPsx is located forward of BG. This area will be stiffened by cleat 6, which must be taken into consideration. According to the present invention, the bending line L will be located forward of both BG and RP, yet behind the point of rotation RPNNN of the conventional NNN system. Beside the outline of the foot, it is indicated where the boot may be rigid (4S) and where it will be less rigid (M).

It is understood that the lines BG, RPsx, L and RPNNN indicated in Fig. 4 are only intended to be approximative and will vary depending on foot shape, foot size, boot construction, binding system, etc.

The invention is based on a cross-country ski binding system comprising a cross-country ski boot 1 and a cross-country ski binding 8, said ski boot 1 comprising a boot sole 2 having a heel section 3 and a front section 4 with a boot tip 5, wherein under the front section 4 of boot sole 2, in the region forming a transition between the metatarsals and phalanges of a foot, a cleat 6 that comprises one or more pins 7 is provided, said cleat 6 fitting into a complementary crib 10 of a binding 8 that optionally comprises a flexor 9, and wherein said binding system has an initial included angle a.

According to the invention, boot tip 5 forward of cleat 6 is (flexurally) softer than any other part of the boot sole 2 so as to yield if the initial included angle p of the binding system is approached, thus providing a reserve included angle 0.

Hence, in order to achieve this particular bending point, the boot tip 5 forward of cleat 6 may have one or more transverse weakening zones or ribs, see Figs. 3b, 9a, 9b, for example. Fig. 7 shows how flexor 9 of the binding is tensioned when the boot is pressed into binding 8. If the boot is not loaded, that is, turned forward or backward relative to the pivot point p, then the boot will be tilted at an angle a as shown in Fig. 5. The angle a is chosen so that the ski is well controlled, i.e., neither the tip of the ski nor the back ski hooks or sinks into the snow. The pretension is also beneficial in preventing the ski from tilting/oscil lating too much.

Boot sole 2 may further comprise a stiffening plate or sole 12 extending backwards from cleat 6, see Figs. 9c, 9d, with said boot sole 2 comprising the stiffening plate or sole 12 having a given bending stiffness kb _P .

Boot sole 2 may further comprise a stiffening plate or sole 13 extending forward of cleat 6, with said boot sole 2 comprising the stiffening plate or sole 13 having a given bending stiffness kf _P .

Alternatively, the boot sole 2, forward of cleat 6, may comprise just a rubber sole material having a given bending stiffness k _g , that is, no stiffening plate or the like is provided in the boot tip 5.

The arrangement according to claims 3 and 4, wherein the bending stiffness kb _P > kf _P .

The arrangement according to claims 3 and 5, wherein the bending stiffness kb _P > kg.

Alternatively, the transition 14 between the rear part of the boot sole 2 up to the front part of the cleat 6 and boot tip 5 is softer, e.g. in that one or more transverse weakening zones or ribs, i.e. some kind of flexing zone making the sole bend in the right place and in the right way, are provided, which in turn means that the weakening zone has a bending stiffness k _ss that is less than the bending stiffness kb _P of stiffening plate or sole 12 that extends backwards from cleat 6, as well as the stiffening plate or sole 13 that extends forwards of cleat 6, where the boot sole 2 comprising the stiffening plate or sole 13 has a given bending stiffness kf _P , so that k _ss < kb _P and k _ss < kf _P , cf. Figs. 9c, 9f.

As mentioned, it may seem obvious that the sole is less rigid further forward, but according to the invention, the sole is soft or flexible in a region located further forward on the sole than what is conventionally considered desirable or natural, i.e., in the area around BG, cf. Fig. 4.

Generally, a sole exhibits a flexibility that is adapted to the biomechanics of the foot, i.e. the sole has a heel section that lifts the heel and supports the ankles and a joint that supports the arch of the foot up to the transition BG between the metatarsals and phalanges of the foot, where the boot is normally the most flexible, whereafter the boot tip is normally made somewhat stiffer in order to protect the toes (and because the pin of a conventional boot is located under the toes and needs stiffness and sole material to be held in place) and to impart a minimum of torsional stiffness to the boot.

Additionally, there has been a clear tendency towards skating boots becoming stiffer, especially in terms of torsional stiffness but also in terms of longitudinal bending stiffness. With the most rigid boots, the ankle joint 15 is becoming the only joint able to flex to any significant extent in a skating boot. With this type of boot, the transition BG between the metatarsals and phalanges of the foot is barely able to flex; in that the sole 12 may be made of a continuous, rigid carbon or plastic material, which does not yield. The present invention is particularly suited for this type of ski boot.

Traditionally, classic technique ski boots have been flexible and thin. The skiers have preferred ski boots that provides maximum proximity to the skis and contact with the surface. Heel stability has also not been considered important. This has changed somewhat in the recent years. The traditional diagonal technique has increasingly been replaced with double-poling and bone climbing. In bone climbing, it seems that the skiers prefer a ski boot that is significantly more torsionally rigid, with respect to both the sole and heel, as a ski boot that is too flexible leads to the heel twisting slightly off the ski. Thus, it is possible that the present invention will also be useful in connection with a classic technique ski boot.

If the boot is to be used for classic technique skiing, or perhaps as a combination boot or a bit less extreme skating boot, it would be possible to make the sole 2 or plate 12 flexible about BG, cf. Figs. 9e, 9f.

Also provided according to the present invention is a cross-country ski boot 1 comprising a boot sole 2 having a heel section 3 and a front section 4 with a boot tip 5, wherein under the front section 4 of boot sole 2, in the region forming a transition between the metatarsals and phalanges of a foot , a cleat 6 comprising one or more pins 7 is provided, said cleat 6 fitting into a complementary crib 10 of a binding 8 comprising a flexor 9, and said binding system having an initial included angle , said boot tip 5, in front of cleat 6, being (flexurally) less rigid than any other part of boot sole 2, said boot sole 2 comprising a stiffening plate or sole 2; 12 extending backwards from cleat 6, said boot sole 2 comprising the stiffening plate or sole 2; 12 having a given bending stiffness kb _P , said boot sole 2, forwards from cleat 6, having a given bending stiffness kf _P ; with kb _P > kf _P , k|.

In the above, kf _P is the bending stiffness of the front plate or boot tip 5, ki is the bending stiffness of the transition L between the rear part of boot sole 2 up to the front section of cleat 6 and boot tip 5 forward of cleat 6, kb _P is the bending stiffness of the back or heel section 4.

Fig. 8 shows an embodiment for the present invention, which basically corresponds to figure 9a.

Figs. 9a-f show different configurations of the present invention. Fig. 9a shows a configuration similar to the one shown in Figs. 2 and 3a-b. Fig. 9b shows another design of cleat 6, in which the bending line or zone L can be moved somewhat backwards. This configuration may provide for a greater overall included angle and possibly better comfort. It may also be better suited for diagonal/classic technique. Fig. 9c shows a bending line or zone L that may consist of a weakening line in the general rubber material of the boot sole. Fig. 9d and 9e show a resilient, responsive bending plate 13 which will provide a certain bending resistance, and which - alone or in cooperation with a separate flexor 9 - can contribute to a flexor function. In such an embodiment, all or part of the bending energy may first be stored and then released when the bending angle is reduced, which may contribute to increase the forward momentum in the ski track. Figs. 9e and f show a configuration in which the sole of the boot also has a flexing zone behind the cleat in the region around or behind the line BG.

Fig. 10 shows an embodiment without a flexor. In this case, the system can be so well balanced that either - at least some - skiers choose to run without a flexor, so it is optional, or the system is delivered without a flexor. It is also possible to have the flexor function integrated in the ski boot, similarly to what is shown in Fig. 9d and/or 9e, in that the ski boot is provided with a resilient, responsive bending plate 13 (ref figs. 9d and 9e, not visible in fig. 10) which will provide a certain bending resistance, and which may contribute to a flexor function. By responsive is meant that as much as possible of the energy used for bending the flexing plate is returned when the flexing plate is allowed to restraighten.

It is to be understood that individual features of the various embodiments may be combined across the exemplary embodiments. For example, the more compact cleat shown in Fig. 9b may advantageously be combined with one or more of the embodiments shown in Figs. 9d through 9f, 10, etc.