The present invention relates to a ski and ski binding according to the preamble of claim 1 and a ski according to the preamble of claim 12. Preferred embodiments are stated in the dependent claims. It is well known that skis for cross-country competition skiing and ski touring is performed with a flex, i.e. the ski bends longitudinally, and is highest in the mid-region. The area under the mid- region of the ski is typically prepared with a grip wax, and brought into contact with the below surface by stride, when the user transfers all his or hers weight to the one ski with which he or her pushes down during each stride. During glide passages the user stands with the weight distributed on both skis and presses down the flex of the skis much less than during stride, so the grip wax will not contribute much to the friction.

In difficult and changing conditions, however, the fact is that despite this simple and elegant solution, it is difficult to obtain sufficient grip particularly in steep uphill slopes and for users who have not developed optimal skiing technique. A number of measures have therefore been tried and proposed to provide better grip during difficult conditions without negatively affecting the glide properties.

It has previously been proposed to make skis with improved glide and grip properties. Such a ski is disclosed in Norwegian patent No. 309928 and in EP 2295120.

One measure that has been proposed is to make the ski base movable under the binding / user's foot, so that it under certain conditions can be brought better in contact with the below surface, regardless of the user's skill level.

One example is shown in WO Publication No. WO 85/02550, which discloses a ski where there is a connection from the front part of the binding, below the boot toe-cap to the ski sole part by a rod which affects the ski sole part so that this moves downwards when the boot is lifted as typically done during stride. The system shown in this publication seems difficult to accomplish in practice, partly because the whole structure as it is shown in the figure, occupies more than half the thickness of the ski and thus necessarily reduces the ski strength. In addition it comprises a plurality of compression springs, presumably to compensate for the fact that the movement down of the sole would otherwise be too extensive, since the movement of the boot is substantial, whereas the movement that is desired to the sole merely is of few millimeters. According to another variant of WO 85/02550, a mechanism of several joints is used for transmitting movement from below the mid-region of the user's foot, but still involving use of large compression springs against the ski sole part, requiring recesses which occupy far more than half the thickness of the ski, which will dramatically reduce the ski strength and affect the ski properties. Norwegian patent application No. 841621 describes another system for the same purpose, in which a part of a ski sole is movably arranged in response of foot movement in a binding. In this case only the mid- lateral part of the sole is movably arranged, while the flanks of the sole are fixed in the entire longitudinal direction. An advantage compared to the solution described above is that the system does not impair the ski construction, but a disadvantage is that the ski sole is divided and there is a risk that snow slips into the longitudinal slot that occurs when only the central, lateral part of the sole flexes down at each stride. If even a rather small amount of snow enters this slot, the sole will not be able to flex back to its original position and cause friction also when you want maximum glide. Boot movement in the binding will affect the ski base directly without any modification or attenuation other than the material stiffness of the flexible elements used, which will change character due to aging and partly with temperature. It will therefore be difficult to get a consistent behavior of the equipment over time and under varying conditions.

Objects

It is thus an object of the present invention to provide a ski and ski binding which enables better grip during stride without changing the ski properties substantially and above all without impairing the ski structure with large cavities.

It is a further object to achieve this by simple means which allow a precise and limited transfer of motion to the ski base without the use of compression springs or other means which will typically change the properties over time or change the properties with varying temperatures. The present invention

The above objects are achieved by the ski and the binding according to the present invention as defined by claim 1.

According to a particular aspect, the present invention relates to a ski as defined by claim 12.

Preferred embodiments are disclosed by the dependent claims. According to the present is provided a ski with flexible under side of the grip zone, where the flexible bottom is pressed down into a convex shape during stride, which gives increased friction against the surface. During the glide stage the flexible underside of the grip zone is again lifted up into a concave shape which reduces the friction against the surface.

This is according to the invention achieved in that the flexible ski base in the grip zone, the ski base in the grip zone, is connected to underside of the ski boot by pivot arms attached to the sides of the ski. The vertical rotational movement of the ski boot is transmitted to the ski boot attachment device. The ski boot attachment device moves a transmission rod which moves at least one rocker arm. When the ski boot, via rocker arm and transmission rod, is not forcing the flexible base to a convex shape, it is held it up from the below surface in concave shape by suitable means such as return springs. To further enhance the effect of the flexible base, a movable and adjustable wedge member can be positioned between the rocker arm and the flexible base or sole part. This wedge can be moved in the longitudinal direction of the ski by a screw or the like, to make the ski more convex or more concave in dependence of the desire to balance the grip and glide properties, alternatively to compensate the users weight.

By the present invention, a limited and precise transmission of movement to the sole portion of the ski is achieved without the use of compensating compression springs or the like wherein the transmission as such includes a gear mechanism. In addition is achieved that the upper part of the ski, which is the main part of the ski and responsible for the inherent characteristics in terms of flex and strength, makes up most of the ski cross section also in the area below the user's foot. The upper part of the ski is not weakened by large cavities that would changes the ski character. In general one might say that the upper part of the ski in the area under the binding, typically comprising more than half of the cross section of the ski, preferably more than 75% of the ski cross section in this area. Required cavity for housing of the transmission mechanism is limited in width and does not impair the ski's construction or strength noticeably.

According to preferred embodiments, the transmission of movement is readily adjustable as further explained below. In a preferred embodiment, the maximum movement of the sole part of the ski relatively to the upper part of the ski is preset and independent of compression springs or the like.

The sole part of the ski comprises in addition to the ski sole a flexible substrate which is attached to the sole and provides a desired combination of strength and elasticity to the sole part. The substrate may be synthetic or natural based and is preferably selected among materials having relatively low specific density. The sole material or the glide surface as such can be of any suitable material, and is typically made in a synthetic material.

The sole part of the ski is continuous throughout the width of the ski so there is no slot in the sole surface into which snow can penetrate during use.

The fact that the binding has a substantially firm attachment to the ski means it is firmly attached to the ski during normal use. However, it can very well be arranged so as to allow being disengaged from the ski when the ski is not in use.

When referring to the "flex" of a ski in the present description, we generally refer to the height of the mid-region ski part over a flat surface when the front and rear ends of the ski rest on the same surface. "Flex" can also refer to the force required to depress the mid-region part of the ski to the ground. In the context of the present description, the term is used in such general terms that there is no need to distinguish between flex in terms of height and flex in the form of force.

Detailed description of the present invention. In the following the invention is described in more detail with reference to the drawings, in which: Figure 1 shows a mid-region section of a ski with movable sole part.

Figure 2a and 2b illustrate the effect of movable sole part in two positions.

Figures 3a and 3b show the present invention in the two positions shown in Figures 2a and 2b. Figure 4 is an enlarged view of Figure 3b.

Figure 5a shows an alternative detail variant with respect to the embodiment shown in Figures 3a, 3b.

Figure 5b shows yet an alternative detail variant with respect to the embodiment shown in Figures 3a, 3b.

Figure 6 shows an alternative variant of the invention.

Figure 7 shows a detail of the present invention relating to all previous versions.

Figure 8 shows a detail with replaceable sole part.

Figure 9a, b show details of a possible attachment mechanism for a ski binding that can be used with the present invention.

Figure 10a, b show details of a possible attachment mechanism for a boot which can be used for the binding shown in Figures 8a, b.

Figure 1 shows the general principle of allowing a mid-region sole part lib of a ski be free from the upper part 11a of the ski, so that it under certain conditions can move away from the upper part of the ski to thereby achieve particular properties, such as extra good grip in uphill slopes without impairing the downhill glide. This principle is as such well known, such as e.g. from .. Figure 2a shows the ski in a situation where the user's weight is on the heel of the boot and preferably his own weight relatively equally distributed between both skis. The ski now describes a curved line that is highest in the middle, under the boot where the grip wax is located, due to inherent flex of the ski,. The ski behaves like any other touring or competition ski in such a situation, and provides desired low friction against the surface. While a conventional ski has a fixed thickness, one might say that the ski with movable sole part in this position is "thin".

Figure 2b shows the ski in a situation where the user is about to make a stride. It is illustrated as taking place uphill, but the same will take place on flat ground. Firstly, the weight of the user is positioned on the foot making the stride. This makes the ski curvature less curved and possibly even straight, which again is just like with any touring or competition ski. In addition is achieved the effect that the sole part of the ski in the area under the user's foot moves away from the upper part of the ski.

The ski becomes thicker in the area under the user's foot. This allows better contact between the sole part comprising grip wax and the below surface than what is achieved solely by transferring weight from two feet to one foot and moving weight from heel to toe. Still, however, this is a feature generally known from WO 85/02 550.

Figures 3a and 3b show details of the specific solution that constitutes the present invention and which allows a fine tuned and not exaggerated movement of the movable sole part lib of the mid-region part of a ski. Figure 3a shows a toe binding comprising a first binding part 12a which is adapted to be secured to the ski upper part 11a in any suitable manner, and a second binding part 12b which is hinged to the first binding part with a hinge 13 having a horizontal axis at across the longitudinal direction. From the second binding part 12b a rod 16 extends down to a transmission mechanism which in the shown illustration has the form of a rocker arm 15, having a first arm 15a and a second arm 15b, the rocker arm being hinged about an axis parallel to the axis of the hinge 13.

More specifically, the rod 16 is attached to the first arm 15a while the second arm 15b is adapted to directly or indirectly affect the sole part lib of the ski when the rocker arm is moved. It will be appreciated that the rod 16 is pivotally attached to both second binding part 12b and to first arm 15a of the rocker arm 15. Figure 3a also shows a heel plate 17, the function of which simply being to support the heel region of the boot in a known manner, vertically and optionally horizontally.

The boot shown with dotted lines in Figures 3a and 3b is not part of the present invention, and the manner by which it is fastened to the toe binding, is not essential. A variation of an attachment mechanism is described further down.

Figure 3b shows the same device as Figure 3a, but in a position where the heel is lifted from heel plate, i.e. in the execution of a stride. Please also refer to Figure 4, which shows the same as Figure 3, but magnified. As further apparent from Figures 3 and 4, this implies that the rod 16 is lifted and pulls up the first arm 15a of the rocker arm 15, while the other arm 15b of the rocker arm moves down. It appears that the first arm 15a is longer than the second arm 15b. This means that the movement of the outer end of the second arm 15b is smaller than the movement of the attachment between the rod 16 and the first arm 15a. One thus obtains thus a "downshift" of the movement, so that a given movement of the second binding part 12b causes a smaller movement of the second arm 15b of the rocker arm and thus a smaller movement of the sole part lib of the ski. This downshift is partly determined by the ratio of the length B along the first arm 15a and the length B along the second arm 15b of the rocker arm. It is furthermore affected by the ratio of the length A from the hinge 13 on the binding to the attachment point 16a for the rod 16 to the second binding part 12b and the length B from the axis 15c to the attachment point 16b for the rod 16 to the first arm 15a of the rocker arm.

Finally the downshift is affected by the fact that the second arm 15b of the rocker arm at the outset is at a given angle relative to the sole part lib of the ski 11, so that only the vertical component of the motion of the second arm 15b of the rocker arm contributes to the movement of the sole part lib of the ski. This last factor implies a safeguard against overloading the sole portion lib, since the selection of an appropriate angle of the second arm 15b results in a given, calculated maximum movement of the sole part at which the second arm 15b is at a vertical position. Any continued movement of the second binding part 12b and rocker arm 15 beyond this point will allow the sole part to move up again instead of being pushed farther away from the upper part of the ski.

Again with reference to Figure 4 the second binding part 12b exhibits a plurality of attachment points at various distances from the hinge 13 so that the attachment point 16a for the rod 16 can be moved as desired in order to achieve a greater or lesser effect on the rocker arm 15. Similarly, the first arm 15a of the rocker arm 15 is shown having a plurality of attachment points at various distances from the axis 15c, so that the attachment point 16b can be moved as desired to thereby obtain a different ratio between the movement of the second binding part 12b and the movement of the sole part lib of the ski 11. It will be appreciated that the rocker arm 15 and rod 16 are hidden in the recesses in the ski 11 and hardly visible. The upper part of the rod 16 will protrude through or beside the first binding part 12a, and thus be visible.

Figure 5a shows an embodiment wherein a pressure-distributing plate 18 abuts against the ski sole part lib in the area where the second arm 15b abuts against the sole part lib of the ski. This entails in less wear on the sole part, and secondly it ensures a smoother transition or a larger radius of curvature that occurs on the sole part of the ski when the rocker arm presses the sole part down.

Figure 5b shows an alternative to the embodiment shown in Figure 5a, the pressure distributing plate 18 'shown in Figure 5b being slightly wedge-shaped and located in a recess 19 in the ski sole part having essentially the same shape as the lower part of the pressure-distributing plate. As indicated by the dotted arrow, the pressure-distributing plate can be arranged to move forward in the running direction to an area where the recess 19 is less deep. In such a case the second arm 15b will sooner engage with the pressure-distributing plate, and will sooner start to move the sole part of the ski away from the upper part of the ski when the second binding part is lifted. This may come as an alternative to, or an addition to, adjustments that can be made by moving the attachment points 16a, 16b at respective ends of the rod 16.

Figure 6 shows a particular variant of the present invention where the regulation of the movable sole portion lib of the ski is done solely by moving or positioning such a wedge-shaped plate positioned between the ski upper part 11a and its sole part lib. The figures show how an operating device located at the ski's upper side is arranged to move the wedge-shaped pressure- distributing plate 18' forward or backward via a spacer 20, for example of sheet steel, which is placed in a channel 21 adapted therefore through the upper part 11a of the ski. In use, it is conceivable that the wedge-shaped plate is moved forward when a climb is to commence, to improve the grip, and moved back when running downhill so as to minimize friction and minimize wear of the wax.

Figure 7 provides an illustration of how the upper part 11a and the sole part lib can be arranged to be held tightly against one another when pressure is not exerted to the sole portion by the rocker arm 15, and to quickly reposition the sole part in the desired position when such pressure ceases. A resilient body 23 is attached to the upper part 11a of the ski with a fastener 24 while a corresponding means 25 is attached to the sole part lib of the ski by a fastener 26, One or both of the cooperating means 23, 25 must be resilient. The skilled artisan will understand that the exact design and the exact number of such cooperating means may vary.

Figure 8 shows a ski according to the invention seen from the side and from below, the movable sole portion lib being replaceable and attached to the upper part of the ski by clips or the like, allowing replacement in case of wear and/ or replacement during change of skiing conditions. For example, one type of movable sole part may be used for dry wax, another one for sticky wax and still another having wax-free, shell patterned ski base.

Figure 9a and 9b show a possible embodiment of a toe binding which can be used in the present invention and in this case will be a part of the second binding part 12b shown in Figures 3 and 4. Figure 9a shows the binding from above and Figure 9b shows a side view. The binding comprises a plate 29 which is provided with two locking tabs 27 and a guiding peg 28.

Figures 10a and 10b show a sole plate 30 for a shoe intended for use with the binding shown in Figures 9a, b. As will be appreciated the boot is fixed by lowering the boot at an angle relative to the binding, so that the broad areas of recesses 31 move down over the respective locking tabs 27. Then the boot is rotated until it is parallel with the ski and in this position it is locked. As a security element locking tabs 27 with a given tensile strength may be used, which will break when a force exceeding the breaking strength is applied. This ensures that the boot is released from the bond before there a major strain occurs on the user's feet or joints. It should be noted that the invention in its general form can be used by per se known toe bindings and in principle with any conceivable binding that allows the user to lift the heel from the ski. The particular variant shown in Figure 10a, b is independent of type of binding.