Technical Field of the Invention

The invention relates to a ski boot sole system suitable for being fixed to a ski by means of a ski binding, the ski boot sole system comprising a structural element made of a fibre material, where the structural fibre element is provided with a front part, a toe part; a metatarsal part forming a continuation of the toe part towards a rear end and possibly a rear part extending from the metatarsal part towards the rear end of the ski boot sole system. The structural fibre element is also provided with a fixing element arranged at the front of the front part, forming an integrated part with, the structural fixing element, being suitable for fixing of the ski boot sole system to the binding, the fixing element being in a form of a transversally arranged pin arranged in front of the ski boot sole system. Background of the invention

At the filing date of the present application, two dominating state of the art ski binding systems exist for use in cross-country and touring skiing and also for roller skies. These ski binding systems are based on the same principle, where a ski boot sole is provided with an transversally arranged pin at the central front part of the sole, arranged at a small height above the top surface of the binding, providing an axis of rotation fixed in the front part of the sole, and where a binding comprises a corresponding locking mechanism for locking the pin to the binding, thereby securing the ski boot sole to the ski, allowing rotation of the front of the ski boot around said transversally arranged pin. The ski boot sole is rotatable around the axis of rotation's axial centre of the pin. The axis of rotation is located in the front of the skier's big toe and approximately 2.5 cm below the big toe while the axis of rotation is located approximately 1 .7 cm above the upper surface of the ski. Such prior art ski boot soles have a relatively thick, rigid sole, in particular, but not exclusively, in the region for the big toe and the front part of the metatarsal part. This is, however, in conflict with the anatomy of a human foot, since the toe part from an anatomical point of view is the part where the human foot is best bendability and where the effect of a kick is created.

Such commercially available state of the art ski boots available on the market at the filing date of the present application have a relatively thick, strong sole, also in the big toe region and the front part region of the metatarsal area of the foot, resulting in a relatively rigid and stiff front part of the sole. This, however, is in conflict with the foot's anatomy during the execution at least of the last phase of a kick when walking and running or skiing, where the flexible and pliable part of the foot is exactly in this metatarsal and toe area. During walking and running the foot is flexed in a continuous curve in the last part of the kick, where inter alia the calf muscles assist in pressing the toes down and backwards - a vital phase of the kick, forcing the kick force downwards and thus increasing the length of the stride and the acceleration. Jogging and running shoes, for example, are therefore made with an extremely flexible and pliable sole in the metatarsal and toe area, in harmony with the anatomy of the foot.

The above described movement during the last part of the kick is not possible with the said ski boot sole and ski binding due to the stiff and rigid front part as specified above. Due to the presence of such stiff and rigid sole front, there is too little flexibility in the front part of the sole to enable the achievement of a running type of movement in the front part of the metatarsal area and the whole toe area during execution of the kick. Consequently, during the initial phase of the execution of the kick, the ski boot will begin to rotate about the axis. From that moment and until the completion of the kick, the ski boot will be lifted up from the ski due to its rotation about the axis, thereby losing its contact and force against the ski and the surface, which means that the resultant force during this final part of the kick is pointing upwards relative to the ski and away rom the snow surface.

Furthermore, with the aid of the inbuilt spring in a ski, the ski's grip-waxing portion is lifted up from the snow, i.e. the grip in this crucial part of the kick disappears. This means that the last an important part of the kick, which could have provided increased acceleration and increased length of stride by means of the major muscle, is lost since groups of the calf, thigh and gluteal musculature cannot be utilized. In short, the kick becomes less efficient since the movement is not completed, as is natural during walking and running.

The term "to complete the movement" is widely used in sport. It is commonly understood that in order to achieve the best possible effect from a movement it must be completed in a natural way and not interrupted prematurely. Well-known examples of such "complete movement" are running and walking, golf, tennis, throwing, shot put, boxing, kicking a football, etc.

The above description of a truncated kick in today's cross-country sport indicates that it is a contributory factor to the steadily increasing use of the arms in cross country skiing, and long touring events are often won today by racers who do not perform a single kick, despite the fact that arm strength normally constitutes only about 20% of the total leg strength. For the average skier who is not able or willing to develop extreme arm strength, this kind of extensive use of the arms is not an alternative.

Recent development within the ski boot and ski binding area has introduced a new type of connection between a binding and a ski boot sole, where the skiers or athletes are given the possibilities of providing a longer and more powerful kick, resulting in a more efficient technique, greater speed and a longer glide and rest phase per stride during diagonal stride and ski skating and also when double poling with heel rise. Such solution provides also a ski boot sole that is pliable in the longitudinal directional of the toe portion and the metatarsal area of the sole, while at the same time providing a sole with a sufficient torsional and transversal stability and rotational stiffness in order to give the skier better control over the skis under all conditions and particularly when skiing downhill. According to such development of combined binding and ski boot, the attachment and pivot point, i.e. the axis around which the boot is rotating, is arranged direct in front of the skier's toes. Such new development is disclosed in the applicants own publications WO 2013/008079, WO 2015/159163 and NO 20161543.

WO 2013/008079 describes a ski boot sole and a ski binding. The sole consist of a front part, a toe part, a metatarsal part next to the toe part, a rear part extending from the metatarsal part to the rear part of the ski boot sole. The front part extends from the front of the toe part to the extreme front part of the ski boot sole. The front part includes of a ski binding attachment consisting of a sideways extension in the form of a clamping bar which is to be locked into a slot on the binding in order to secure that forces are absorbed in the binding. The clamping bar is arranged transversely with respect to the longitudinal, main direction of the sole. The binding consists of a base plate, a positioning channel, a slot in the ski binding's side walls and centre axis. A locking mechanism is attached to the base plate. A ski boot attachment consists of a clamping bar and a clamping arm with hinged connection to the base plate. Clamping arms which is hinged in base plate has a point of rotation located immediately above the base plate. At this point of rotation the lever arm is located which is connected to a point of rotation on the locking plate. The locking plate in turn is arranged to a point of rotation on the base plate. When closing the binding, the locking plate will transmit forces via the lever arm and clamp the clamping arms down around the extensions.

WO 2015/159163 describes a ski binding system intended for arrangement of a ski boot having a boot tip that is flexible in the longitudinal direction and equipped with a transverse locking pin in the forward part of the boot tip, and which is wider than the boot tip such that the locking pin protrudes outwards on each side of the boot tip. The ski binding is suitable for cross-country, classic style, skating/freestyle and roller skies. According to this solution the axis of rotation will be in the order of 25 to 30 mm in front of the position of the big toe (hellux) inside the boot.

A problem identified with a sole as discloses in WO 2013/008079 and WO 2015/159163 is that a residual tension in the front part of the sole, due to the 2-3 cm distance between the transversal pin and the toe position on the sole (and the upper) were experienced, introducing a disturbance at least during the last part of the kick.

EP 1559337 relates to a tread sole has a rear section (1 1 ) with heel (13) and a slightly dish-shaped front section which at least on the shaft side is continuously smooth and with an unchanged predetermined overall thickness at least in the region of the metatarsal zone (M) has a considerably reduced thickness (d) which is preferably 30 to 35 % and maximum 50% of the overall thickness (h) of hard and soft material. An outsole cover can be welded or stuck onto the tread side of the tread sole.

US 2008/047168 relates to a Nordic ski boot support and attachment mechanism having a toe piece that slidably engages a ski, a lever that is pivotably attached to the toe piece, a rigid forefoot support that is fixedly attached to the lever, a heel support that is pivotably attached to the forefoot support, and an ankle support that is pivotably attached to the heel support. The lever engages the toe piece at the left and right side, including a moment arm therebetween that is at least one half inch long. The lever may include a recess that engages a rearward projection on the toe piece. A heel piece is also slidably disposed on the ski providing a second projection. The heel support includes an engagement member that engages the second projection when the lever is in the down position.

WO 2013/058658 relates to a ski shoe sole comprising a sole core, outer sole portions, wholly or partially surrounding lip portions, and binding attachment means. The ski shoe sole comprises a sole core that forms a frame structure and at least one further sole element which is designed to interact with the frame structure.

It is experienced that there is a need for lifting the foot sole of the skier or athletes up, slightly above the binding. There is also a need for a sole that is better adapted to the foot curvatures of the skier, and still improvement of the skier's control of the ski, in particular when the skier's foot is resting on the ski.

Moreover, there is a need for a solution supporting a "complete movement" at the end of the kick.

NO 20161543 describes a ski boot sole and a ski binding. The sole comprises a structural element made of fibre, where the structural fibre element is provided with a front part, a toe part, a metatarsal part forming a continuation of the toe part towards a rear end and possibly a rear part extending from the metatarsal part towards the rear end of the ski boot sole system. The structural fibre element includes a fixing element arranged at the front of the front part, forming an integrated part with the fixing element, being suitable for fixing the ski boot sole system to the binding, the fixing element being in a form of a transversally arranged pin. The front part with the pin forming the fixing element and the front of the big toe position on the toe part of the sole coincide both in height and longitudinal position along a

longitudinal direction of the sole system.

A problem identified with a sole as discloses in NO 20161543 is that the transversal pin protruding/extending sideways out from the front part is vulnerable to external forces leading to bending of the pins, hence making fixing the sole system to the binding difficult or impossible.

There is thus a need for a solution protecting the pin in a better way and still maintaining the short distance of a user's big toe with the axis of rotation and the upper surface of the ski.

Summary of the Invention

The main principle applied according to the present invention is to allow the skier to complete the kick movement fully out with the entire ski length still in full contact with the supporting snow, even during the round off part of the kick. In this respect the position of the rotating axis with respect to the position of the big toe grip on the upper sole surface, and the mechanical properties of the ski boot sole in this front region are of essence and importance. The present invention is based on the principle that the sole is made bendable in longitudinal direction in areas where the foot also is bendable, i.e. following the anatomy of the human foot. This means that the front of the sole, i.e. the area closely associated with the rotating axis and the toe part of the sole, and in particular, the big toe (hallux), is made bendable to cater for the required corresponding bendability of the toe region of the skier's foot, thus allowing the kick to be more effective. Regarding the metatarsal and the part towards the rear end, the sole may be made more rigid, since this part of a human foot is less bendable.

The main object of the present invention is to provide a ski boot sole

arrangement securing a "complete movement", i.e. securing that the force from the skier's kick during the last part of the kick is transferred down into the ground, avoiding or at least substantially reducing the lift off of the a substantial part of the ski during the last part of the kick. Moreover it is an object of the present invention to exploit the resistance of a plate shaped body against rotation around its three principal axes, establishing and maintaining a locking effect between a ski boot sole and a ski binding against rotation during the stage where the ski boot is in a locked position, pressed down onto the binding.

An object of the present invention is to provide a ski boot sole system that is flexible and bendable in the region where the human foot is flexible and bendable, i.e. in the toe region and the front part of the metatarsal region, and more rigid in areas where the human foot does not require a corresponding flexibility or bendability.

Yet another object is to provide a ski boot sole system where the pressure exerted by the skier during the kick is directed down into the supporting surface.

An object of the invention is to provide a ski boot sole which offers the skier the possibility of a longer and more powerful kick. This will result in a more efficient technique, greater speed and a longer glide and rest phase per stride during diagonal stride and ski skating. This entails a more efficient use of the major muscle groups, with the calf muscles also coming into play.

Another object of the invention is to provide a sole for a ski boot which gives the skier good control of the skis under all conditions, particularly but not exclusively downhill.

Another object of the present invention is to provide a ski boot sole where the toes, and in particular the first toe, i.e. the hallux (the big toe), is as close to the pivot point of the sole both in vertical and horizontal direction of the ski boot sole as possible.

Yet another object of the invention is to provide a ski boot sole that is configured not to touch or interfere with the side walls of the ski track as this will have a braking effect.

Similarly, it is an object of the invention to provide a ski boot sole which together with the binding system, provides a robust and reliable connection between ski binding and ski boot sole.

It is also an object of the invention to reduce the weight of ski boot.

Yet another object of the present invention is to provide a solution protecting the pin in a better way and still maintaining the short distance of a users big toe with the axis of rotation and the upper surface of the ski.

The objects of the present invention are obtained by means of a ski boot sole system as further defined by the independent claim, while alternatives, embodiments and variants are defined by the dependent claims. According to the invention it is provided a ski boot sole system suitable for being fixed to a ski by means of a ski binding, the ski boot sole system, comprising a structural element made of a fibre material, where the structural fibre element is provided with a front part; a toe part; a metatarsal part forming a continuation of the toe part towards a rear end and a rear part extending from the metatarsal part towards the rear end of the ski boot sole system, the structural fibre element also being provided with a fixing element arranged at the front of the front part, forming an integrated part with the fixing element, suitable for fixing the ski boot sole system to the binding, the front part (FP) with the pin forming the fixing element (13) is placed in a recess located in the middle of the front part (14) of the structural element (1 1 ) and the ski boot sole, extending from front (F) into toe part (TP) and the front of a big toe position on the toe part (TP) of the sole (10) coincide both in height and longitudinal position along a longitudinal direction of the sole system (10).

In addition, the fixing element may also be in a form of at least one, preferably two transversally arranged pins arranged in front of the ski boot sole system. The front part of the ski boot sole with the pin formed fixing element and the front of the toe part coincide both in height and longitudinal position along a longitudinal direction of the sole system.

According to one embodiment, the structural fibre element may preferably be embedded in a flexible rubber or plastic material covering the structural fibre element on all sides.

The shape of a lower surface of the ski boot sole system may be made complimentary to a shape of an upper surface of a binding, the bottom surface of the ski boot sole element and preferably also the corresponding width of the structural fibre element may, at least along the front part, have a transversal width substantially corresponding to the width of the binding. According to one embodiment, said transversal width of the may generally be uniform at least along the toe part.

According to one variant, the transversal width may generally be uniform from the toe part at least to the middle region of the metatarsal part.

The embedded structural fibre element may in the end region of the metatarsal part be provided with a part projecting laterally sideways with respect to the front area, the transition from the front area to the laterally sideways projecting part being curved. Moreover, the sideways projecting part may preferably, but not necessarily, be arranged at the end of the generally uniform part, the sideways extending part of the fibre sole insert preferably extending outwards on the outer side of the foot. In addition, the front part of the fibre sole insert may be configured to be complementary to an upwards facing surface of the binding..

Moreover, the ski boot sole may at its front end, be provided with an upwards projecting lip, preferably formed of the same rubber or plastic material as the ski boot sole, intended to form a cushion against the binding when the boot is pivoted around a centred placed pin.

Said lip may be structurally supported by an upwards extending extension of the reinforcing fibre element insert, extending upwards inside the lip and embedded in a rubber or flexible plastic material

According to the present invention the upper surface of the ski boot sole, i.e. the surface intended to be in contact with the foot blade of the skier, is configured and positioned in such way that touching point of the skier's big toe onto the sole surface when the boot is put on the skier's foot, will for all practical purposes be at the point of rotation of the ski boot around the pivot axis formed by centred placed transversal pin attachment at the front of the sole. Moreover, the referenced big toe will also for all practical purposes, be in immediate or close contact with the sole surface at the axis of rotation of the boot with respect to the binding. In such way it is secured that all the forces in the kick will be directed down into the ground, exploiting the forces of the skier, since the toe and in particular the big toe and first part of the metatarsal part of foot are the parts forming the main basis for the kick,.

According to the present invention, the vertical distance between the upper surface of the binding surface and the center of rotation for the sole, should preferably be as little as possible, preferably in the range between 1 mm to 10 mm, preferably in the order of ± 4 mm, i.e. as small as practicably possible, while the distance from the centerline of the transversal pin, to the front tip position of the big toe (hallux) on the sole, should be as small as practically possibly and preferably in the range of 5 to 15 mm. Moreover, the distance between contact surface for the tip of the big toe on the sole surface and the center of rotation of the sole should likewise be as small as possible, closer to 5 mm than 15 mm. Such distances form the bases for an effective kick, directing the forces applied by the skier more or less directly downwards into the ground.

A major advantage is the resistance of the sole, at least in the toe part and the metatarsal part to bend sidewise around the longitudinal axis of the sole, but still being bendable or pliable in a lateral direction. Due to this property, possibly combined with the use of the laterally extending fins, configured to fit into

corresponding slots or recesses in the binding, a stable solution is provided when the boot sole is resting on the ski. This property gives the skier an enhance control of the ski when running downhill or when passing curves.

By reducing the position of the laterally extending pin from 2.5 -3 cm in front of the position of the tip of the big toe to more or less to the front tip of the big toe, the possibilities of fatigue at the ski boot tip is reduced. Moreover, rupture or breakage as a consequence of a fall down hill is also reduced.

By having a ski boot with not parts extending out in front of the tip of the upper of a boot, the possibility of stumbling or damage to the ski boot tip is also reduced. At the same time the exposure to wear and tear is likewise also reduced.

Another advantage is that the tip of the boot rotates together with the direction of motion of the skier's foot, eliminating bending during normal use and also in case of a fall, for example at large speed downhill. Moreover, tests have shown that such solution provides a better contact between the boot and the ski, giving the skier a better feeling, better stability, and ski control during skiing.

The proposed position of the point of rotation just in front of the big toe and more or less just above the binding is also more in harmony with the human anatomy.

Yet another advantage according to the present invention is that the ski boot sole offers the skier the possibility of a longer and more powerful kick, enabling the skier to more fully flex the foot in a continuous curve in the last part of the kick, where inter alia the calf muscles contributes in the pressing of the toes downwards and backwards - a vital phase of the kick. The resulting effect is increased stride length and acceleration without to any substantial degree increasing the total lactate production of the skier. Moreover, this will result in a more efficient technique, greater speed and longer glide and rest phase per stride during diagonal stride and ski skating.

Brief Description of the Drawings

Exemplified embodiments of the present invention will now be described, by way of example only, referring to the reference where:

Figure 1 shows schematically a view seen from below of an exemplary embodiment of a ski boot sole for the left foot according to the present invention;

Figure 2 shows schematically in perspective a view of the sole disclosed in Figure 1 , seen from above;

Figure 3 shows schematically a front view of the ski boot sole disclosed in

Figure 1 ; Figure 4 shows schematically a view seen from below of an alternative embodiment of a ski boot sole for left foot according to the present invention, showing transversally arranged pins projecting sideways out of the front part;

Figure 5 shows schematically an alternative embodiment of the ski boot sole according to the invention, showing a sole provided with sideways extending or projecting fins ;

Figure 6 shows schematically a horizontal view of one embodiment of the structural element to be embedded in the ski boot sole;

Figure 7 shows schematically another embodiment of the structural insert to be embedded in the ski boot sole;

Figure 8 shows schematically another embodiment of the structural insert to be embedded in the ski boot sole; and

Figures 9a-9c shows schematically a side view of the front of the structural insert, indication possible positions of the structural fibre plate with respect to the centre of the transversal pin.

Detailed Description of Exemplified Embodiments disclosed in the Figures

The following description of the exemplified embodiment refers to the accompanying drawings. The drawings illustrate exemplified embodiments of the invention configured to be integrated with the upper boot configuration of a ski boot and further configured to be attached to a ski by means of a binding fixed to the top surface of the ski. The exemplified embodiments disclosed in the drawings should not be understood as a limitation to the scope of protection of the invention.

The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention.

Instead, the scope of the invention is defined by the appended claims.

In the drawings only the sole system is disclosed. It should be noted, however, that the sole will be fixed to an upper, i.e. the part of the boot above the sole, such upper may be of any suitable and known type without thereby deviating from the inventive idea.

Reference throughout the specification to "one embodiment" or "an

embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout the specification is not necessarily referring to the same embodiment. Moreover, when reading this document it should be appreciated that when the ski boot sole 10 is mention, it refers to the entire sole, made as an integrated unit including an insert 1 1 of a fibre material with an inherent flexibility in the longitudinal direction of the sole and less flexibility in lateral direction, i.e. a direction perpendi- cular to the longitudinal direction. Further, the insert 10 may be made of a reinforcing material, such as glass fibre, carbon fibre, thermoplastic carbon fibres or other types of fibre having more or less the same properties, or basalt fibre. The surface of the sole 10 may be provided with a texture or a thin additional layer for securing proper frictional grip without deviating from the inventive idea. Said surface may also be provided with a purpose designed profile, mirroring a corresponding surface on the binding to be used.

In principle the sole 10 comprises a non-rigid sole configured to fit a ski binding, the sole 10 being made of a pliable and bendable material with certain inherent stiffness and mechanical properties and/or possibly also combined with a ribbed surfaces, elements, or the like, proving the required stiffness and mechanical properties. The sole 10 also comprises an embedded insert 1 1 made of carbon fibre, basalt fibre, glass fibre or any other type fibre material contributing to the mechanical and/or strength properties as further discussed below.

The heel of the ski boot sole system 10 may also be provided with a stiffening insert without thereby deviating from the inventive idea.

For clarity and simplicity, the upper is not disclosed and may take any required shape or design without deviating from the inventive idea.

Figure 1 shows schematically a view seen from below of an exemplary embodiment of a ski boot sole 10 for the left foot according to the present invention. The sole 10 comprises a toe part TP, a metatarsal part (MP) under the metatarsal area of the foot, a front part (FP), and a rear part (RP). The sole 10 is given a general shape adapted to the foot print of a foot. In this respect it should be noted that that the general shape of the sole is at certain parts in the longitudinal direction wider that the width of the ski (not shown) and also the binding (not shown). The metatarsal area MP is adjacent to the toe part TP. The rear area RP extends from the metatarsal area MP to a rear end R of the ski boot sole 10. The rear part RP of the boot comprises a boot heel or heel area HR. The front part FP extends from the toe part TP to the tip F of the ski boot sole 10, said two parts coinciding for all practical purposes. The front part FP comprises a ski binding attachment 20 which is attached to a ski binding, which will be described in detail below. According to the exemplary embodiment shown in Figure 1 , the insert or the structural fibre element 1 1 is terminated at the end region of the metatarsal part MP. At its front end F, i.e. the end intended to be fixed to the binding, the insert 1 1 is provided with a slot with a pin 13, preferably of a metal such as steel, the pin 13 being arranged in a transversal direction across the slot. Along its end parts, the pin 13 is embedded in and surrounded by the fibre material forming the fibre insert 1 1 , while the fibre insert with pin is embedded in the sole, thereby securing anchoring of the pin 13 with respect to the fibre insert 1 1 and the ski boot sole 10. According to the embodiment shown, the pin 13 is visible in the slot placed centred at the central of the embedded front part FP, allowing locking to a binding at the mid part of pin 13. The pin 13 may for example be made of metal, carbon fibre, plastic, polycarbonate, POM, PEM, PET, aluminium or composite materials and the part intended to be embedded in the fibre insert may be given a surface or texture providing proper bonding to the fibres and/or matrix used for making the fibre insert. Said pin serve as axis for rotation of the sole with respect to the fixing point on the binding.

Moreover as indicated in the Figure the insert 1 1 is provided with a part 14 having more or less uniform width, such part 14 with uniform width extending from the front F towards and partly past the toe part TP, terminated more or less in the middle region of the metatarsal part MP. In this region the insert 1 1 is provided with an enlarged rounded end 15 extending sideways out from in a direction corresponding to the outside of a human foot, i.e. to the right for the sole the right foot boot and to the left for the left boot when seen from above. One purpose of such lateral extension is to increase the resistance against lateral bending in the plane of the insert 10.

Since most of the bindings available on the marked are provided with vertical ribs or fins extending both upwards and in longitudinal direction of the binding, and since such ribs fins commonly arranged along the outer edges of the binding, and moreover since the total width of the sole 10 in the metatarsal area is wider than the width of the ski and the binding the upper surface of the sole 10 must be lifted up in order avoid contact between the sole and the vertical sides of a ski track. At the same time it is importance to allow the ski boot sole 10 to be in firm contact with the binding, at least during downhill runs. Accordingly, the bottom side of the sole 1 o is provided with a recess 17 at least on both sides of the sole 10 in the region of the toe part TP and at least halfway into the metatarsal part MP. It should be noted that the depth of such recess 17 on both side of the sole 10 corresponds more or less to the height of the upwards extending ribs or fins on the binding, leaving a central part along the corresponding remaining part of the sole 10 being in contact with the binding surface when the ski boot is attached to the ski. Said central part has a width corresponding to the width of the insert having uniform width. It should be appreciated that the invention is not limited to a solution where the insert 1 1 is given a shape as disclosed. It should be appreciated that the insert may extend for example to the heel region HR of the sole 10.

At the front part FP, the sole 10 is provided with a lip 18 projecting upwards from the sole 10, the lip being made of the same material as the sole 10, i.e. a rubber or plastic material. Moreover, a fibre insert is embedded in the lip 18, the fibre insert forming an integral part of the fibre insert 1 1 and configured to reinforce the lip 18 and providing the lop with an inherent flexibility in addition to possible inherent flexibility in the rubber or plastic material used. The purpose of the lip is inter alia to provide a damping effect against an adjacent binding housing when the boot is rotated around the transversal axis.

The thickness of the insert may be more or less uniform along the entire length of the insert 1 1 . Alternatively the insert 1 1 may be given a varying thickness in longitudinal direction, configured to vary the rigidity or bendability as and if required. The thickness may preferably be in the order of 0.5-1 .5 mm, the variation being achieved by adding additional ayes of fibres and/or thicker layers of fibres. The invention comprises a fibre sole as illustrated in Figure 1 , with a transversal extension in the front part of the tip of the fibre insert 1 1 . The extension may be between 200% and 800% thicker than the remaining part of the insert 1 l and it protrudes outwards on each side of the sole's 10 front part FP. The fibre insert 1 1 substantially determines the ski boot's mechanical properties. The fibre insert 1 1 may extend along the whole length or a part of the sole 1 1 and the of the ski boot and forms an integrated part of the boot's bearing element together with the part into which the fibre insert is embedded. Hence, when reading this document it should be understood that when one mentions the ski boot's sole, reference is made to the ski boot's fibre sole and the rubber or plastic part into which the fibre insert 1 1 is embedded. The ski boot will may also be provided with a wear surface or may be provided with a surface texture, but this is very thin and will be so pliable that it will not contribute to any significant extent to the ski boot sole's mechanical properties. The wear sole should therefore be regarded as an addition to the ski boot sole according to the present invention.

The sole's 10 front portion has a complementary shape of a binding's guide channel and the fibre insert goes directly into a binding's attachment device, and the fibre insert 1 1 therefore constitutes the mechanical connection between ski boot and binding. The invention exploits a property of oriented fibre layers. In an oriented fibre layer, all the fibres lie in one direction and the modulus of elasticity is generally twice as large along the fibres compared to across the fibres. In combination with a variation of the number of fibre layers in the sole's different zones, this can be exploited in the construction of a ski boot sole where the desired moduli of elasticity are modelled in the sole's different zones both in the longitudinal direction and transversal direction.

The fibre insert may also be constructed with a layer of braided fibres, or designed as a combination thereof. In a braided fibre layer, the fibres are lying braided with the fibres at an angle of for example 15, 45 or 90 degrees to one another. Layers of braided fibres have slightly more rigid properties than oriented fibres.

The fibre insert is relatively flexible in the sole's longitudinal direction, from the ball of the toe up to the portion in front of the toes, while it is relatively stiff from the heel and up to the ball of the toe. At the same time the sole is relatively rigid towards torsion.

It should be appreciated that the insert may be reinforced in lateral direction by mean for example of additional bundles of fibres (not shown) forming an integrated part of the insert 1 1 , arranged across the insert 1 1 and spaced apart, thereby enhancing the resistance of bending in the plane of the insert, while maintaining the bendability in longitudinal direction.

Figure 2 shows schematically in perspective a view of the sole disclosed in Figure 1 , seen from above. In order to fit an upper (not shown) and enable assembly with the upper, the side edges may be provided by curved inner surfaces along the rim or periphery of the sole in order to provide proper glued connection between the sole 10 and the upper. As indicated in Figure 2 an upwards projecting lip 18, more or less arranged at an orthogonal angle with the main direction of the sole 10 is arranged. The lip 18 has a concave surface facing inwards, i.e. the surface intended to be more or less in contact with the toes, while the surface facing outwards, i.e. intended to be in contact with the binding is convex. The upper edge of the lip 18 is preferably curved. As indicated the lip is for all practical purposes arranged close to and above the pin 13. Further, as shown in Figure 2 the sole 10 is also provided with a downwards protruding heel element 19.

Figure 3 shows schematically a front view of the ski boot sole disclosed in Figure 1 showing the upwards extending lip 18 and the transversally arranged pin 13 placed in centred slot at the front of the sole 10, immediately beneath the lip 18.

Figure 4 shows schematically an alternative embodiment of the ski boot sole 10 according to the invention, showing a sole 10, wherein the fixing element 13 being extended with fixing element 13, projecting sideways out of the front part of the sole. Figure 5 shows schematically an alternative embodiment of the ski boot sole 10 according to the invention, showing a sole 10 provided with sideways extending or projecting fins 20. The fins 20 may be configured so as to fit into recesses or indents in longitudinally arranged ridges or fins on the top surface of the binding. The length, thickness and the width of the fins or lips on the bottom surface of the ski boot sole 10 is sufficient to at least partly fit into the referenced recesses, slots or indents on a binding ridges, enabling the ski boot sole 10 to be locked when the skier presses the boot downwards onto the ski. As indicated in Figure 5, also the insert 1 1 is provided with such fins or lips, coinciding with the corresponding lips in the rubber or plastic material of the sole 10, thus reinforcing said fins in the rubber sole 10.

In order to reinforce or strengthens said ribs 20 further, transversely arranged bundles 24 of carbon or basalt fibres may be arranged crosswise, with their ends fixed to the fins. Alternatively, said bundles 24 of fibres may constitute the fins 20. The number of fins 20 may be one or more.

The pin 13 is located and forms an integrated part of the front edge of the sole 10 and is preferably centred relative to the ski sole 10. The pin 13 may for example be in the form of a transversal element integrated in the front part FP of the ski boot sole 10 and centrally placed in slot of the ski boot sole's 10 front part FP. The visible length of the pin 13 may for preferably be between 20 mm and 40 mm. The diameter of the pin on the outside of the plate-shaped sole tip may for example be between 1 mm and 10 mm, preferably between 2 mm and 4 mm. The thickness of the pin in the ski boot sole in the guide channel's side walls may for example be between 1 mm and 16 mm, preferably between 2 mm and 8 mm.

Figure 6 shows schematically a horizontal view of one embodiment of the structural element or insert 1 1 to be embedded in the ski boot sole 10; while Figure 7 and 8 shows schematically other embodiments of the structural insert 1 1 to be embedded in the ski boot sole. Common for the two different embodiments shown is that each insert 1 1 is provided with a laterally arranged pin at the front, extending across the form of the insert and being embedded in the fibre material so as to provide an integrated unit with the fibre material. Moreover the pin 13 is centrally placed in central slot in the front F, configured to be in engagement with

complimentary locking arm on the binding. As indicated in the Figures, the extreme front of the insert is reinforced by additional and/or thicker layers of fibre material.

Another feature in common for the three different embodiments shown is the shape of the insert 1 1.The front part 14 of the structural insert 1 1 , i.e. at least the toe part TP, has a constant width and preferably also a constant thickness, this part 14 being configured to be bendable and flexible allowing the toe part TP to follow the bending of the skier's foot and in particular the bendability of the toe part and at least the front of the metatarsal part of the skier's foot.

In addition, the rear part of the structural insert 1 1 is provided with a part extending sideways to the side intended to be beneath the outer side of the skier's metatarsal part MP. The transition from the part 14 to the bulbous part 15 is curved and continuous without any abrupt transitions on both sides.

The major difference between the embodiment in figure 7 and the two other embodiments in figure 6 and 8 is the fixing element 13 being extended with fixing elements 13 projecting sideways out of the front part of the sole.

The major difference between the embodiment shown in figure 8 and the two other embodiments in figures 6 and 7 is the fins or sideways projections on both sides of the toe part 14, i.e. the part having more or less parallel sides. As indicated, the structural insert 1 1 may as an option be provided with fibre bundle

reinforcements 24 arrange laterally between a pair of fins or projections 20.

According to the embodiment disclosed in Figure 8, two fins or projections 20 are shown on each side. It should be appreciated however, that the number of fin may vary without thereby deviating from the inventive idea. Moreover, the fins 20 may be arranged on only one side or both and may be adapted to the upper shape of the binding.

Figures 9a-9c shows schematically a side view of the front of the structural insert 1 1 , indication possible positions of the structural fibres and fibre mats with respect to the centre of the transversal pin 13. As indicated the structural insert may be embedded where the insert plat portion 14 fins arranged in a tangential relation to the transversal pin 13, tangential to the lower side of the transversally arranged pin 13 or the upper side of the transversally arranged pin 13, ref. Figure 9a and 9b respectively. Figure 9c discloses a variant where the structural insert plate portion 14 is centrally oriented with respect to the transversally arranged pin 13.

The pin 13 and the lip 18 will provide stability for the sole 10 when it is fixed in a ski binding , particularly with regard to lateral movement of the sole 10 relative to a ski binding.

The sole 10 comprises a material in which the longitudinal elasticity in the x- direction, the transversal elasticity in the y-direction and torsional rigidity in the sole 10 are determined by the properties of the fibre layer insert 1 1 . The deciding factor for the rigidity of the sole 10 and/or flexibility in the x-direction and y-direction is determined by the number of fibre layers in the construction of the insert 1 1 , together with the fibres' orientation in the sole's various parts/zones. The ski boot sole's geometrical shape in the different zones of the ski boot sole is also a deciding factor for the flexibility and rigidity.

In general, the rule for fibres is that the E-modulus along the fibres is double that of those across the fibres.

The ski boot sole's outer sole is preferably designed without grooves and preferably comprises a thin wear layer 13 of rubber or the like, with a modulus of elasticity E between 10 MPa and 200 MPa.

A typical range of values for the E-modulus for various fibres is:

Carbon composite, oriented and woven prepreg 45 degrees with modulus of elasticity between 20 GPa and 190 GPa and glass fibre between 60 GPa and 80

GPa.

In the invention the insert 1 1 is a composite material comprising layers of carbon fibre, for example oriented carbon fibre or woven carbon fibre of the prepreg type where the layers are placed on top of one another and glued together or fixed with a resin, such as epoxy. Alternatively, the fibre insert 1 1 may comprise glass fibre, for example oriented glass fibre or a combination of carbon fibre and glass fibre, or natural fibre and various types of artificial fibre.

In the present invention the rear part RP is rigid in the longitudinal direction (x- direction) and transversal direction (y-direction) and also torsional rigidity in the longitudinal direction (about the x-axis). The front part FP is flexible/pliant in the longitudinal direction and rigid in the transversal direction and also torsional rigidity in the longitudinal direction. The metatarsal area MP is flexible in the longitudinal direction (x-direction), rigid in the transversal direction (y-direction) and also torsional rigidity in the longitudinal direction. The toe part TP is flexible in the longitudinal direction (x-direction), rigid in the transversal direction (y-direction) and also torsional rigidity in the longitudinal direction (about the x-axis).

A rigid ski boot sole may therefore be considered rigid in the longitudinal direction (x-direction) by an adult of around 75 kg if the sole has the following rigidity:

A force of 12 Newton with 20 mm deflection and a force of 120 Newton with 85 mm deflection and a torque of 1 Nm with a torsional angle of 5 degrees and a torque of 20 Nm with a torsional angle of 40 degrees.

Correspondingly, a pliable ski boot sole will be considered pliable in the longitudinal direction (x-direction) by an adult of around 75 kg if the sole has the following rigidity:

A force of 1 Newton with 20 mm deflection and a force of 32 Newton with 85 mm deflection and a torque of 0.4 Nm with a torsional angle of 5 degrees and a torque of 10 Nm with a torsional angle of 40 degrees. The deflections and the torsional angles indicated above are found by taking force/deflection measurements according to standard procedures for measuring deflection which will be know to a person skilled in the art. The deflection results indicated above were found by a sole being clamped to a bench and a force applied to the sole at a length L = 140 mm from the clamping point, and the deflection caused by the force at L = 140 mm was measured. Similarly, the torsional angle was found by a sole being clamped to a bench and a torque applied to the sole at a length L = 140 mm from the clamping point, and the torsional angle of the sole caused by the torque at L = 140 mm was measured.

It should be mentioned that whether a ski boot sole 10 is considered rigid or pliable is also a subjective assessment which in addition is dependent among other things on the skier's weight and whether the ski boot/binding is used on skis for skating, classic cross-country, Telemark skiing etc. In spite of the indicated absolute physical measurements as a definition of pliability and rigidity, it should therefore be noted that the terms "rigid" and "flexible" as used herein should be interpreted as "perceived as rigid" and "perceived as flexible", depending on the skier's weight, the size of the ski boot, the type of ski discipline, etc.

The same result as indicated above can be obtained using woven carbon fibre or woven glass fibre, or in combinations thereof. There are different weave configu- rations and angles between the fibres, where for example a 45 degree angle may be employed between the fibres.

It should also be mentioned that flexural rigidity/flexible in the longitudinal direction should be understood as flexural rigidity/flexible on deflection about an axis in the transversal y-direction. Correspondingly, flexural rigidity flexible in the transversal direction should be understood as flexural rigidity/flexible on deflection about an axis in the longitudinal x-direction. Torsional rigidity in a longitudinal direction should also be understood as torsional rigidity about a longitudinal axis in the x-direction.

As an alternative to oriented fibres as in the above table, woven fibres may be employed, for example prepreg with a 45 degree angle between the fibres. These are somewhat stiffer and may result in overall fewer layers than appear in the above table. Depending on the thickness of a layer supplied by the producer, the above- mentioned number of layers in the different layers may have to be increased, retained or reduced.

The examples of different layers in the sole are indicated in fig. 10 and in table

1 . Here it can be seen that layer number 2 and 5 are common to all the zones of the sole, FP, TP, MP and RP, thereby providing a continuous sole. Furthermore, it should be noted that the layers may be partially overlapping as indicated in fig. 10, i.e. some layers continue partly into the adjacent sole part, thereby giving a more gradual change in the flexibility of the sole.

Tests have been carried out at Olympiatoppen where the same skier has tested ski boots with a sole according to the present invention and ski boots with NNN and SNs sole system. The test were performed on roller skies on a ski tread mill under the exact same conditions where length of stride and the kick were measured, together with lactate pulse level also were monitored and measured. The following comparative improvements, based on average measurements, were found:

Skating Classic

Improvement Improvement

Double 32 % 14,5 %

Single 10 %

Paddle 5 %

In spite of the improvement, surprisingly both the pulse and the lactate content were more or less unaffected, while longer strive and gliding length were observed. According to experts, this means higher top speed and an improved working economy.