At present snowboards are normally designed with a flat sole surface between the tips at both ends. For steering the board is edged and the weight distributed between the feet in the two bindings.

Alpine skiing is a field which is related to snowboarding. In Alpine pair skis it is known to have the sole surfaces designed with angled portions in partial areas of the sole surface.

Thus in Norwegian patent 172 170 there is disclosed an Alpine pair ski, which on a maximum 20 cm long front portion has a sliding surface which diverges upwards when the steel edge diverges outwards from the ski's longitudinal axis. The object of this ski is to turn with the least possible loss of kinetic energy. In PCT/N095/00030 there is disclosed an Alpine pair ski, which on a portion which is longer than 20 cm has a sliding surface which diverges upwards when the steel edge diverges outwards from the ski's longitudinal axis. The object of this ski is to turn with the least possible loss of kinetic energy, but in this case with a more harmonious design than in that which is described in Norwegian patent 172 170.

In Norwegian patent no. 301 964, which corresponds to EP 748245 there is disclosed an Alpine pair ski with a flat first sliding surface and lateral surfaces provided with an almost continuous concave inward curve between a first transition line which defines the transition from a tip portion to a front portion and a second transition line which defines the transition from the main portion to a rear portion. The lower lateral edge between the transition lines describes an almost continuous curve. The sole on both sides of the first sliding surface comprises further sliding surfaces, which extend upwards from the edge of the first sliding surface to the lower lateral edges of the ski with an upward curve. The additional sliding surfaces extend in the

longitudinal direction of the ski, at least from the first and second transition lines respectively towards a transverse line behind the middle of the ski and in the portion of the ski where the binding is attached, the width of the ski at the transverse line being equal to the least width of the ski between the transition lines. The upward curve in the lower lateral edge on the additional sliding surfaces increases substantially with the ski's increasing width in the direction of the two transition lines.

An Alpine ski as described in this publication has been shown to be very well suited to Alpine events and the angled sliding surfaces, which even with a relatively slight edging of the ski can be pressed into contact with the base, giving improved turning technique and grip on the base.

The present invention is based on the development of Alpine skis which is described in Norwegian patent no. 301964. Even though both skis and snowboards are used for downhill skiing and turning in Alpine terrain, there are nevertheless significant differences. This difference is based both on the difference in design of the two products and on the manner in which the product manoeuvres. In skis the weight is distributed with a foot in a binding in the central portion of each ski and the ski, which is elongated and relatively narrow, at least for most of its length, will, when a pressure load is applied in the central area, be able to be forced to assume different positions against the base. In the case of a snowboard the performer stands with both feet on a substantially wider board and he will steer the board by bodily movements and by distributing his weight between the front and the rear of the board. Since the board is wider and shorter and the weight distribution different the board will not only be more rigid than a ski but will also be steered in a different way.

In the present invention it has been found that a number of the principles which have been developed in connection with the ski according to Norwegian patent no. 301964 in modified and developed form can be employed for further development of a snowboard, resulting in a marked improvement in their handling characteristics.

On this basis, therefore, it is the object of the invention to provide an improved snowboard. This is achieved by means of a snowboard which is characterized by the features which will be presented in the patent claims.

The snowboard according to the present invention differs from the above- mentioned, known ski designs in the requirement, amongst other things, that the secondary lateral areas of the board should be substantially twisted. By twisted it should be understood that the angle of the lateral area against the base, viewed in the transverse direction of the board, increases from the central portion up to the front area at the tips.

From the dynamic point of view a snowboard differs from a ski in many ways, for reasons of both design and mode of application, as indicated above.

A ski with a certain inward curve will be twisted upwards at the tip and rear tip when edged, since the skier presses with his foot in the middle of the ski and the counter-forces from the base will twist the ski, reducing the aggressiveness at the front and the rear due to the fact that the sole is flatter against the snow at the front and the rear than in the middle. In contrast with this the performer on a snowboard will stand with both feet placed not so far from the tips, with the result that in relative and absolute terms the snowboard has less length than the ski to generate a twisting moment. It will therefore not be so easy to twist the snowboard. It is therefore absolutely necessary to give the snowboard a dynamically correct shape at the manufacturing stage. This is achieved according to the invention by combining dimensions which are specific to the snowboard with selected features which are known to be employed in connection with skis, since these selected features together will give the snowboard an optimal dynamic adaptation. Thus it is the combination of the features indicated in the patent claims which make it possible to utilise the features known from skis for an improvement of an alternative product, viz. a snowboard.

There is therefore a fundamental difference between ski and board, and in the invention it has surprisingly been shown that by means of adaptation and modification of features known from the field of skis with regard to the design of twisted surfaces, it has been possible to develop a snowboard which is adapted to the dynamics which apply to skis.

When the twisted board according to the invention is placed on the snow, it can already have a better dynamic shape than the surface the board is capable of achieving, since the board according to the invention is produced with a twisting of the sole adapted to where the weight is actually placed on the board, with regard to the ideal twisting which is desired.

It has further been shown that there are significant safety aspects associated with a specific design of raised sliding surfaces with regard to landing after jumping with the snowboard. It is a fact that falls with snowboards result in many injuries, which are far more serious than the speed would indicate. The snowboard according to the present invention is also designed to increase safety in landing after a jump, due to the fact that it is not so aggressive in the edge area during landing.

The more curved the steel edge in the snowboard's edge area is, the greater tendency it has to cut away in an uncontrolled fashion when landing after a jump, especially when making an almost flat landing. The invention will therefore provide greater safety benefits the more inward curve the snowboard has. By allowing the board to be almost flat along its entire width from the central portion a reasonable edge grip can also be secured when the board is flat against the snow. On the front and rear portions of the board the right and left parts of the sole are twisted upwards, thus providing a less aggressive steel edge, but at the same time the board has to be formed in such a manner that it has a good edge grip when turning. Thus a boat shape, in which the cross section shows curved lines near the steel edge will be unsuitable, since the angle at the steel edge will then be too large to give a good edge grip. The snowboard described with a cross section in the front and rear portions consisting of three straight lines (fig. 2) will ensure both a less aggressive edge grip during landing after a jump and adequate edge grip during turning.

The width is a further significant difference between ski and snowboard. A narrow ski can easily be edged 45°. The much wider snowboard is usually run much flatter than a ski. A great deal of edge grip will therefore easily be lost with a snowboard when the secondary surfaces are too acutely angled relative to the first sole surface. The invention solves this special problem for snowboards by means of the special design of raised lateral area from the following criteria: 1. The secondary lateral area must have a certain minimum width which is greater than for most skis, thus achieving a greater uplift with less angling of the secondary lateral area relative to the first sole surface.

2. The secondary lateral area is raised from the plane of the first sole surface by being twisted upwards when moving from the middle towards the tips.

3. The cross section shows the sole as three substantially straight lines in those parts of the board where there are secondary lateral areas.

The invention will now be illustrated in more detail by means of the embodiments which are presented in the drawings, in which: fig. 1 illustrates the underside of a snowboard according to the invention, fig. 2 is a cross section of the snowboard in fig. 1, viewed across the board in the areas indicated by A, B C, fig. 3 is a variant of the embodiment in fig. 1, fig. 4 is a third embodiment of the invention, fig. 5 is a variant of the embodiment in fig. 1, fig. 6 is a variant of the embodiment in fig. 5, fig. 7 is a further variant of the invention, fig. 8 is a further variant of the invention, figs. 9 and 10 illustrate the snowboard according to the invention, viewed from the side and from one end.

Fig. 1 illustrates the underside of a snowboard. The hatched sole surface 1, called the first sole surface, is completely flat when the board is pressed against a flat base. The secondary lateral areas 2a and 2b in line 5a-5b form zero degrees with the first sole surface, and up to line 4a-4b form a substantially increasing angle with the first sole surface, viewed in cross section as shown in fig. 2. In the same way the secondary lateral areas 2c and 2d in line 7a-7b form zero degrees with the first sole surface, and up to line 8a-8b form a substantially increasing angle with the first sole surface. The secondary lateral areas 2 therefore appear to be twisted, if not over their entire length, to such an extent that they have the function of a twisted surface. The front tip 3a and rear tip 3b and central transversal axis 6a-6b are also shown.

Fig. 2 illustrates three cross sections of the snowboard in fig. 1, taken directly across from fig. 1. In order to illustrate the increasing angle from line 5a-5b to line 4a-4b the angles are slightly exaggerated, thus making it easy to see that there is a larger angle nearest line 4a-4b. In cross section the sole surfaces are shown to be completely straight, even though in the transition between first sole surface and the secondary lateral areas there may be a certain degree of rounding.

Fig. 3 illustrates a design in which the secondary lateral areas are terminated reasonably parallel to the steel edge.

Fig. 4 illustrates a design in which the secondary lateral areas are widest at the transition to the tips at lines 4a-4b and 8a-8b respectively, gradually narrowing as one approaches lines 5a-5b and 7a-7b respectively. In this embodiment the degree of twisting will be less than in the other embodiments which are illustrated.

Fig. 5 illustrates approximately the same design as fig. 1. Here the board is envisaged moving straight ahead with the board completely flat against a hard base. Only the steel edges outside the first sole plane 1 are then in contact with the snow, while the performer's weight is envisaged evenly distributed over the entire length of the first sole plane. As an illustration we have chosen to let the central portion of the snowboard be the same length as the sum of the length of the secondary lateral areas on the same side. Thus the lengths 4a-5a and 7a-8a are here equal to 5a-7a, and correspondingly on the opposite side. F/2 is the force from the base on the steel edge over half the length of the board, while d/2 is the average distance from the centre 6 of the performer to the force's point of attack on one side. M indicates torque.

Fig. 6 illustrates the same design as fig. 5, but with a completely flat sole. F is the force from the base on the steel edge along the entire length of the board, while d is the average distance from the centre 6 of the performer to the force's point of attack on one side. M indicates torque.

Figures 7 and 8 illustrate two further examples of snowboards designed according to the invention. In the embodiment according to figure 7 the hatched sole surface, i. e. the first sole surface is designed with equal, relatively narrow width along the whole board, but has a central portion at line 6-6 which makes a"soft"transition into the lateral areas. A certain

degree of asymmetry in the secondary areas is indicated, even though symmetry is preferred. In the embodiment in figure 8 the hatched first sole surface is designed narrowing from line 6-6 to end lines 4-4 and 8-8, which is first illustrated from lines 5-5 and 7-7. The portion of the first sole surface between these two lines is continued right out to the edge. In all embodiments the lateral areas are designed in a twisted form.

The illustrated examples will provide boards which have different handling characteristics, but will all provide the special advantage which is achieved by means of the invention.

Finally, figures 9 and 10 illustrate the snowboard according to the invention, viewed from the side and from one of the ends. On this scale the angles had to be exaggerated relative to the preferred angle in order to clearly illustrate the principle. In figure 10 the twisting of the lateral areas can be seen indicated on the underside, with the maximum angle in the transition to the tip.

Four tables are now presented illustrating the twisting angle for the lateral areas in the snowboard according to the invention. Thus table 1 gives four examples of snowboards with a constant cross section for the first sole surface. Table 2 exemplifies an embodiment with constant width for the secondary lateral areas, while table 3 gives the angle for boards with variable width for the first sole surface in the secondary lateral areas. Table 4 illustrates an example of an asymmetrical snowboard.

The tables are only intended as a demonstration of the increasing angle against a flat base from a cross section at the central area to cross sections at regular intervals distributed in the direction towards the ends of the board.

It should be obvious from the above that despite the choice and combination of special features which are partly known from ski technology, many modifications are possible. Further development according to the invention is based on the combination of selected features in such a manner that a result is obtained which is unique for snowboards. In the invention a selection of features and dimensions have been made which together provide an improvement.

Table 1. Four examples of a snowboard with a constant width of the first base surface.

For simplicity we use in these examples snowboards with circular sidecut, and symmetry along both the longitudinal and transversal central axis.

Total width Total width Length (6)- (8) Length (6)- (4) Sidecut at (8) at (6) radius 290 250 650 650 10573 Distance Total width Width of the 1. Width of each Cross sectional angle between from the tip base surface secondary first base and secondary areas areas 1 2 3 4 0 50 100 150 290,0 80,0 105,0 3,0 1,0 2,0 2,2 200 284,1 80,0 102,0 2,7 0,7 1,9 2,2 250 278,6 80,0 99,3 2,4 0,3 1,8 2,1 300 273,7 80,0 96,8 2,1 0 1,7 2 350 269,2 80,0 94,6 1,8 0 1,6 1,8 400 265,1 80,0 92,6 1,5 0 1,5 1,6 450 261,6 80,0 90,8 1,2 0 1,4 1,4 500 258,5 80,0 89,3 0,9 0 1,2 1,2 550 255,9 80,0 88,0 0,6 0 0,9 1 600 253,8 80,0 86,9 0,3 0 0,6 0,8 650 252,1 80,0 86,1 0 0 0,3 0,6 700 250,9 80,0 85,5 0 0 0 0,4 750 250,2 80,0 85,1 0 0 0 0,2 800 250,0 80,0 85,0 0 0 0 0 850 250,2 80,0 85,1 0 0 0 0,2 900 250,9 80,0 85,5 0 0 0 0,4 950 252,1 80,0 86,1 0 0 0,3 0,6 1000 253,8 80,0 86,9 0,3 0 0,6 0,8 1050 255,9 80,0 88,0 0,6 0 0,9 1,0 1100 258,5 80,0 89,3 0,9 0 1,2 1,2 1150 261,6 80,0 90,8 1,2 0 1,4 1,4 1200 265,1 80,0 92,6 1,5 0 1,5 1,6 1250 269,2 80,0 94,6 1,8 0 1,6 1,8 1300 273,7 80,0 96,8 2,1 0 1,7 2,0 1350 278,6 80,0 99,3 2,4 0,3 1,8 2,0 1400 284,1 80,0 102,0 2,7 0,7 1,9 2,1 1450 290,0 80,0 105,0 3,0 1,0 2,0 2,1 1500 1550 1600 Where the angle is zero, the first base surface extend to the steel edges In these example the width of the first base surface is chosen to be 80 mm, but it could just as well have been set at any value between 40 mm and 160 mm Table 2. Four examples of a snowboard with a constant width of the secondary areas.

For simplicity we use in these examples snowboards with circular sidecut, and symmetry along both the longitudinal and transversal central axis.

Total width Total width Length (6)- (8) Length (6)- (4) Sidecut at (8) at (6) radius.

290 245 650 650 9400 Distance Total width Width of the 1. Width of each Cross sectional angle between from the tip base surface secondary first base and secondary areas areas 5 6 7 8 0 50 100 150 290,0 140,0 75,0 3,5 1,0 2,0 3 200 283,3 133,3 75,0 3,1 0,8 1,9 2,7 250 277,2 127,2 75,0 2,7 0,6 1,8 2,4 300 271,6 121,6 75,0 2,3 0,4 1,7 2,1 350 266,6 116,6 75,0 1,9 0,2 1,6 1,8 400 262,0 112,0 75,0 1,6 0 1,5 1,6 450 258,0 108,0 75,0 1,3 0 1,4 1,4 500 254,6 104,6 75,0 1,0 0 1,2 1,2 550 251,7 101,7 75,0 0,7 0 0,9 1 600 249,3 99,3 75,0 0,4 0 0,6 0,8 650 247,4 97,4 75,0 0,2 0 0,3 0,6 700 246,1 96,1 75,0 0 0 0 0,4 750 245,3 95,3 75,0 0 0 0 0,2 800 245,0 95,0 75,0 0 0 0 0 850 245,3 95,3 75,0 0 0 0 0,2 900 246,1 96,1 75,0 0 0 0 0,4 950 247,4 97,4 75,0 0,2 0 0,3 0,6 1000 249,3 99,3 75,0 0,4 0 0,6 0,8 1050 251,7 101,7 75,0 0,7 0 0,9 1,0 1100 254,6 104,6 75,0 1,0 0 1,2 1,2 1150 258,0 108,0 75,0 1,3 0 1,4 1,4 1200 262,0 112,0 75,0 1,6 0 1,5 1,6 1250 266,6 116,6 75,0 1,9 0,2 1,6 1,8 1300 271,6 121,6 75,0 2,3 0,4 1,7 2,1 : 1350 277,2 127,2 75,0 2,7 0,6 1,8 2,4 1400 283,3 133,3 75,0 3,1 0,8 1,9 2,7 1450 290,0 140,0 75,0 3,5 1,0 2,0 3,0 1500 1550 1600 Where the angle is zero, the first base surface extend to the steel edges In these example the width of the scondary areas are chosen to be 75 mm, but it could just as well have been set at any value between 40 mm and 105 mm Table 3. Four examples of a snowboard with a variable width of the first base surface.

For simplicity we use in these examples snowboards with circular sidecut, and symmetry along both the longitudinal and transversal central axis.

Total width Total width Length (6)- (8) Length (6)- (4) Sidecut at (8) at (6) radius 280 240 600 600 9010 Distance Total width Width of the 1. Width of each Cross sectional angle between from the tip base surface secondary first base and secondary areas areas 9 10 11 12 0 50 100 150 280,0 40,0 120,0 2,0 0,8 1,2 1,8 200 273,6 50,0 111,8 1,8 0,6 1,1 1,6 250 267,8 60,0 103,9 1,6 0,4 1,0 1,4 300 262,5 70,0 96,2 1,4 0,2 0,9 1,2 350 257,8 80,0 88,9 1,2 0 0,8 1 400 253,6 90,0 81,8 1 0 0,7 0,8 450 250,0 100,0 75,0 0,8 0 0,6 0,6 500 246,9 110,0 68,5 0,6 0 0,5 0,4 550 244,4 120,0 62,2 0,4 0 0,4 0,3 600 242,5 130,0 56,2 0,2 0 0,3 0,2 650 241,1 140,0 50,6 0 0 0,2 0,1 700 240,3 150,0 45,1 0 0 0,1 0 750 240,0 160,0 40,0 0 0 0,0 0 800 240,3 150,0 45,1 0 0 0,1 0 850 241,1 140,0 50,6 0 0 0,2 0,1 900 242,5 130,0 56,2 0,2 0 0,3 0,2 950 244,4 120,0 62,2 0,4 0 0,4 0,3 1000 246,9 110,0 68,5 0,6 0 0,5 0,4 1050 250,0 100,0 75,0 0,8 0 0,6 0,6 1100 253,6 90,0 81,8 1,0 0 0,7 0,8 1150 257,8 80,0 88,9 1,2 0 0,8 1,0 1200 262,5 70,0 96,2 1,4 0,2 0,9 1,2 1250 267,8 60,0 103,9 1,6 0,4 1,0 1,4 1300 273,6 50,0 111,8 1,8 0,6 1,1 1,6 1350 280,0 40,0 120,0 2,0 0,8 1,2 1,8 1400 1450 1500 Where the angle is zero, the first base surface extend to the steel edges In these examples the width of the first base surface is chosen to be 40 mm at (4) and (8) and then the width increases towards the middle.

Table 4. An example of an assymmetric snowboard For simplicity we use in these examples snowboards with circular sidecut, Total width Total width Length (6)- (8) Length (6)- (4) Sidecut at (8) at (6) radius.

255 220 750 650 16080 Distance Total width Width of the 1. Width of each Cross sectional angle between from the tip base surface secondary first base and secondary areas areas 0 13 50 Right Left 100 150 255,0 80,0 87,5 2,8 2,4 200 250,5 80,0 85,2 2,6 2,3 250 246,3 80,0 83,1 2,4 2,2 300 242,4 80,0 81,2 2,2 2 350 238,8 80,0 79,4 2 1,8 400 235,6 80,0 77,8 1,8 1,6 450 232,6 80,0 76,3 1,6 1,4 500 230,0 80,0 75,0 1,4 1,2 550 227,6 80,0 73,8 1,2 1 600 225,6 80,0 72,8 1 0,8 650 223,9 80,0 71,9 0,8 0,6 700 222,5 80,0 71,2 0,6 0,4 750 221,4 80,0 70,7 0,4 0,2 800 220,6 80,0 0 850 220,2 80,0 70,1 0 0 900 220,0 80,0 70,0 0 0 950 220,2 80,0 70,1 0 0 1000 220,6 80,0 70,3 0 0 1050 221,4 80,0 70,7 0,2 0 1100 222,5 80,0 71,2 0,4 0,2 1150 223,9 80,0 71,9 0,6 0,4 1200 225,6 80,0 72,8 0,8 0,6 1250 227,6 80,0 73,8 1,0 0,8 1300 230,0 80,0 75,0 1,2 1,0 1350 232,6 80,0 76,3 1,4 1,2 1400 235,6 80,0 77,8 1,6 1,4 1450 238,8 80,0 79,4 1,8 1,6 1500 242,4 80,0 81,2 2,1 1,7 1550 246,3 80,0 83,1 2,2 1,8 1600 Where the angle is zero, the first base surface extend to the steel edges In these example the width of the first base surface is chosen to be 80 mm, but it could just as well have been set at any value between 40 mm and 160 mm