BACKGROUND ART AND PROBLEMS The need of quickly being able to change bindings on a ski has increased as a consequence of the latest development. On one hand it has for a time in the ski rental business, which has experienced a continued increased number of users, which probably depend on the increasing number of different skis to choose from in combination with the, in many cases, high price for new skis. On the other hand there is a new kind of need because of the latest progress in the ski field. The reason is that telemark skis of today has become close to identical with an alpine ski. It therefore becomes more and more common that if you want a good telemark ski, you buy an alpine ski and mount a telemark binding on it. Consequently there is today the possibility to use the same ski for both alpine skiing and telemark skiing, but there is no good solution for quick change of binding on a ski for alpine skiing to a ski with telemark binding. Since a binding intended for telemark skiing differs essentially from a binding for alpine skiing, there has to be a complete switch of bindings to change from one to the other.

Consequently there is a need of an easy and quick way to perform a change of bindings.

From EP 437 172 there is known a fastening device for a ski binding, comprising a front attachment and a rear attachment which are intended to be fixed to a ski and a longitudinal base plate for attachment of a ski binding, wherein said base plate is provided with the first connection means for turning fixed attachment of the base plate with the interacting second connection means at said front attachment respectively third connection means at said rear attachment and wherein said base plate by means of a looking means is non fixed attachable to one of said attachments but provided

longitudinal movable at the second attachment, to make the base plate easy to move in and out of interaction with said attachments and quick and easy to fix respectively release with said looking means.

A solution according to EP 437 172, however, presents a number of disadvantages.

Firstly the design of the attachment of the base plate is less desirable from a strength point of view, since the attachment use protruding tabs at the ends of the base plate, which tabs cause low torsional stiffness of the attachment of the base plate. Since there can be a very high torsional force between ski and boot during alpine skiing and it is extremely important that the skier can control the movements of the ski, this is an essential disadvantage. Furthermore the design make the production of the base plate relatively complex and thereby expensive. Further, the attachment of the binding comprises a non desired large number of different details, which have to be assembled at mounting/changing of the ski binding unit including base plate. In addition the complex/detailed design will make it relatively expensive and heavy, which of course is not desirable.

BRIEF DESCRIPTION OF THE INVENTION The object of the invention is to eliminate or at least minimize the disadvantages mentioned above. This is achieved by a fastening device for a ski binding as defined above, wherein said first connection means has the same cross sectional shape along the entire base plate and said second connection means has the same cross sectional shape as said third connection means, and that said connection means are positioned both front and rear to interact close to the longitudinal edges of the base plate.

Thanks to the solution according to the invention there is provided a new kind of fastening device for a ski binding, which enables a user to quickly and easy change from one pair of bindings to another. Consequently it is hereby achieved that in a simple way the same ski can be used for alpine, telemark and/or randonnée. In addition the solution according to the invention is very cost efficient. Hereby are new possibilities for ski rentals created, more models of alpine and/or telemark skis can easy and cost efficient be offered to customers. The solution imply not only cost advantages from production point of view but also cost efficiency according to handling because of its simplicity.

For the individual user it gives additional possibilities of simplification and cost saving, since users who hitherto needed to bring two or more pair of skis with purpose to practise different kind of skiing now just need to bring one pair of skis and a desired number of bindings.

BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in detail by way of example to the accompanying drawings, in which: Fig. 1 shows a top view of a ski provided with a preferred fastening device for a ski binding according to the invention, Fig. 2 shows a cross sectional view of a rear attachment according to Fig. 1, Fig. 3 shows a cross sectional view of a front attachment according to Fig. 1, Fig. 4 shows an exploded view of a fastening device for a ski binding according to Fig.

1, Fig. 5 shows a fastening device for a ski binding according to Fig. 1 provided with a telemark binding, Fig. 6 shows a fastening device for a ski binding according to Fig. 1 provided with an alpine binding, Fig. 7 shows a modification according to the invention referring to the fixation of the base plate, Fig. 8A and 8B shows modifications according to the invention related to the connection means between the base plate and attachment elements, Fig. 9 shows a first modified embodiment of the invention, and Fig. 10 shows a second modified embodiment of the invention.

According to additional aspects of the invention apply that: -Said base plate has same cross sectional shape along the entire length, and is preferably produced by extrusion, -Said base plate comprise edge portions that are extending across the plane in which the base plate generally extend, these edge portions helps to increase the strength of the base plate.

-Said first connection means comprise a inwardly open, longitudinal groove in each longitudinal edge of the base plate.

-Said second connection means and said third connection means comprise male element intended to be provided inside said groove.

-Said male element are provided at a distance sufficient from the upper surface of the ski to leave an open space between the upper surface of the ski and the lower part of the base plate, to avoid direct contact between the base plate in the area of the attachments and the ski.

-At least one of said attachments, preferably both, is made of injection moulded plastic, preferably POM.

-Said base plate is made of metal, preferably aluminium.

-Said stop means is a screw.

DETAILED DESCRIPTION OF THE INVENTION In Fig. 1 there is shown a preferred embodiment of a fastening device for a ski binding according to the invention shown, seen from above. There is shown a base plate 1, which is fixed in a front 2 and a rear 3 attachment on the upper side of a ski 4. It is depicted that the front attachment 2 is provided with a stop means 28, which define the stop/fixed position of the base plate in relation to the front attachment 2. Further it is shown that the plate 1 is provided with a relatively short crosswise narrow slot 19 approximately at the middle of the plate, which function is to easy and safely position the attachment 1, 2,3 in desired position in relation to the ski (e. g. just above the centre of the ski mark) and also the binding/boot (which also usually has a middle marking) in relation to the plate 1. This marking on the plate enables that all bindings will be mounted in the same position on different plates and in this way will be in correct position regardless on to which ski it is mounted.

Fig. 2 shows a cross section of a rear ski binding attachment according to Fig. 1. It is shown that the rear attachment 3 is screwed onto the ski with a plurality of screws 31. It should be noticed that these screws are positioned at a relatively large distance from each other, with purpose to give optimal strength to the attachment. Between the screws there is a plane portion 32 with a lower surface, which is in contact with the upper surface of the ski 4. This plane portion 32 change, on the opposite side of the screws, to an upwardly portion that present outwardly protruding lips 33,34. These lips 33,34 are provided inside the grooves 14A, 14B, which shape are adopted to the lips 33,34 to get a fitting relatively free from play, at the same time as there is enough play for a easy translation of the plate. The grooves 14A, 14B are provided in each longitudinal edge portion 13A, 13B of the base plate 1. The base plate 1 is in contact with the attachment 3 with horizontally provided surfaces 16A, 16B close to the edge portions 13A, 13B.

These surfaces 16A, 16B interact with the upper surfaces 33A, 34A of the lips 33,34.

The grooves 14A, 14B in the base plate 1 has a kind of U-shape, so the lower part of the base plate is formed by the edge means 15A, 15B that surround the lips 33,34. The lips 33,34 are provided at a distance enough above the ski to create a space 35A, 35B between the lower portion of the base plate 1 in relation to the ski 4 in connection with the attachment 3. The base plate 1 is in connection with this, rear attachment 3, not fixed but can move lengthwise, which on one hand has the purpose not to affect the properties of the ski in a negative way and on the other hand to imply less stress for

parts comprised in the binding attachment. In this regard it is an advantage that spaces 35A, 35B exist between the ski and the base plate 1, to eliminate undesired pinching forces to occur.

Fig. 3 shows in cross section a rear attachment with base plate according to Fig. 1. It is shown that the base plate 1 also in this cross section has exactly the same shape as the backend. According to the preferred embodiment the base plate 1 is produced by extrusion, which imply that the base plate get exactly the same profile in cross section along the entire length. It is also shown that the profile of the front attachment 2 essentially, regarding the interaction with the base plate 1, has exactly the same shape as the rear attachment 3, i. e. with protruding lips 23,24 which position the base plate by means of insertion in the grooves 14A, 14B. As a difference in relation to the rear attachment there is though a central protrusion 27 provided with a coaxially arranged hollow shaped space for a nut 22. Further there is a hole 11 for a screw 12 which is intended to interact with the nut 22. When the screw 12 has been tightened to the nut 22, the base plate is fixed in this position. Further, above the base plate 23 of the attachment there is a protruding stop means 28 provided in the front portion of the front attachment 2, which stop means 28 defines the position for the base plate 1, when this is in position to be fixed with the screw 12.

Both the front attachment 2 and the rear attachment 3 are preferably made of plastic, preferably POM and are preferably produced by injection moulding/moulded casting.

One advantage for this kind of material in the attachments is that a low coefficient of friction is obtained in combination with good abrasion resistance.

For one thing, low friction will facilitate when mounting/dismounting the base plate 1, for another thing it implies that the base plate easy can slide in a longitudinal direction in relation to the rear attachment 3 during use. Further is a acetal plastic, like POM, preferably from the point of view that it can endure very low application temperatures, e. g.-40°C. In addition it implies cost advantages, especially for large batches.

According to a preferred embodiment of a ski binding attachment according to the invention the plate is made approximately 570 mm long and approximately 68 mm wide and with a total height of approximately 12 mm. The weight of the fastening device for a ski binding can be kept on a low level, approximately 300 g/unit, thanks to the choice of material.

Fig. 4 shows an exploded view of a fastening device for a ski binding according to Fig.

1-3. It appears clearly that the lips 33,34 respectively 24,25 extend along the entire

length of respective attachment, to receive large contact surface for the base plate at the same time as a preferably large grip area is obtained from a strength point of view for turning/lifting the base plate 1 in relation to the attachments 2,3.

Fig. 5 shows the fastening device for a ski binding according to the invention with a telemark binding 5 mounted on the base plate 1.. The telemark binding 5 comprises a front attachment plate 5A, a cable part 5B and a heel part 5C provided near the rear part of the cable part 5B. The attachment plate 5A is fixed to the plate 1 in any suitable manner, e. g. with a number of screws recommended according to the manufacturer, that obtain good securing of the aluminium plate 1.

Fig. 6 shows a fastening device for a ski binding according to the invention with an alpine binding 6 mounted on the base plate 1. There is a toe part 6A mounted in a suitable way, preferably with screws, in the front area of the base plate and a heel part 6B is mounted in the rear area of the base plate.

When changing from a telemark binding according to Fig. 5, the user only needs to release the lock screw 12 and then pull the base plate 1 rearward until it is completely free from both the front 2 and rear attachment 3. Next the user can easy mount another pair of bindings, e. g. the one that is shown in Fig. 6, by means of guiding the base plate 1 on from behind, where the grooves 14A, 14B in the base plate 1 engage with the lips 33, 34 in the rear attachment whereupon the base plate 1 quickly and easy can be pushed forward to also be connected with the front attachment 2, in a similar way, until the front edge of the base plate 1 impinge against the stop means 28. Subsequently the stop screw 12 is again put in place and tightened. After that the ski is ready for use, but with another binding.

Fig. 7 shows that instead of a lock screw 12, the front attachment 2 can be arranged with an integrated stop means 12A, which through elasticity can either bring the base plate 1 to lock or to release it.

Fig. 8A and 8B shows that other shapes than the above described preferred embodiment according the integrated connection means can be used in combination with the invention. Fig. 8A shows that male/female elements are in principal inverted in relation to what is described above, but Fig. 8B except in some differing shape, also shows that another location of the lock means 12B, 12B'can be provided.

Fig. 9 shows a first modified embodiment of a fastening device for a ski binding according to the invention. Instead of letting the rear 3 respective the front attachment 2 constitute of separate elements, here is shown that in some applications a longitudinal base plate advantageously can be used where the front 2 respective rear attachment 3 constitute integrated parts of the longitudinal base plate. One advantage of this embodiment is that the base plate 1 will be in engagement with the attachment plate 2,3 along the entire length, which secure that the base plate 2 is completely fixed in relation to the base plate along the entire length.

Fig. 10 shows further a modified embodiment according to the invention, wherein an additional attachment plate 7 is provided between the front 2 and the rear attachment 3.

Like in Fig. 9, a solution according to Fig. 10 provides a safer positioning of the base plate 1 in relation to the attachments. Such a solution can be particularly preferred when the distance between front and rear attachment point is relatively large in relation to the extension of the sole and the ski boot which is applied at the base plate 1.

The invention is not limited to the above shown, but can be varied within the scope of the following claims. Consequently it is for example evident that the shown male/female shape of the integrating connection means can have many different shapes within the range of the ghist of the invention, e. g. a completely inverted shape where male and female switches place from base plate to attachment. Further, horizontal respective vertical surfaces do not necessarily have to be used for the interaction between the connection means, but also inclined surfaces may advantageously be used.

It is also evident that the described choice of materials is no kind of limitation, but that many different kind of metals, plastic and composite materials can be used, separate or in combination. Instead of a slot 19 to facilitate mounting, it is obvious that e. g. a line or other kind of marking can be used for the same purpose.