WO2016024920A1

WO2016024920A1 - Skis and snowboard with specific sidecuts

Info

Publication number: WO2016024920A1
Application number: PCT/SI2015/000020
Authority: WO
Inventors: Andrej GRABAR
Original assignee: Grabar Andrej
Priority date: 2014-08-14
Filing date: 2015-05-22
Publication date: 2016-02-18
Also published as: SI24780A

Abstract

The invention relates to skis and snowboard for a new way of skiing and snowboarding. The skis and snowboard are characterised by a sidecut defined by two straight lines forming an angle at their junction and which sidecut is either shortened or extended or shifted differently on the left and the right side of the ski / snowboard. Different skis and snowboards are provided for left and right push- off leg. The possibility of use of ski pairs consisting of two skis with different sidecut angles is given. New concept of ski use is provided where four different ski pairs can be assembled by combining two skis for left and two skis for right push-off leg (slalom, giant slalom, left push-off leg, right push-off leg).

Description

SKIS AND SNOWBOARD WITH SPECIFIC SIDECUTS

DESCRIPTION

Technical field

[0001] The systems and methods described herein relate to sporting equipment, specifically skis and snowboards, in particular isocentric skis and isocentric snowboard for a new way of skiing and snowboarding.

Background of the invention

[0002] Today skis and snowboards generally use a circular sidecut with a radius typically between 10 m and 24 m that enables riding on the edges in circular turns without slipping. At high velocities extreme accelerations of several G can be achieved which result in enormous centrifugal forces applied on the skier. These often result in severe injuries, especially of the knees and the spine and can lead to long-term fatigue of joints and back. Furthermore, with today's skis and snowboards riding on the edges without slipping is possible only when the radius of the turn is equal to the radius of the sidecut - when this is not the case, slipping occurs and the skier / snowboarder must compensate the loss of balance by increasing tension of the body while losing speed due to increased friction (stick-slip motion).

[0003] Generally, due to the high centrifugal forces and the enforced driving radii, the skis with circular sidecut are very aggressive towards the human body at the same time lacking in flexibility and manoeuvrability on the account of stronger edge grip. This is why in recent years both in recreational and competitive skiing the sidecut radii have been getting larger and one of the reasons why in recreational skiing the classical "carving" skis are not as popular anymore and have been to a large extent replaced by new types of skis such as rocker skis, free ride skis, all mountain skis, etc.

Summary of invention

[0004] The invention relates to skis and snowboards, in particular isocentric skis and isocentric snowboard for a new way of skiing and snowboarding. The isocentric skis and isocentric snowboard enable a constantly adjustable effective radius of the sidecut; constant re-centring of the moving centre of the turns; skiing / snowboarding adjusted to natural body movement, different for the right and the left side of the body. The invention provides a new way of ski use by combining two left and two right skis into four different ski pairs, each suitable for a different style of skiing (slalom, giant slalom, left push-off leg, right push-off leg).

[0005] The technical problems solved by the invention are improved manoeuvrability and responsiveness of the skis / snowboard, higher achievable velocity of the skis / snowboard, higher stability and easiness of skiing / snowboarding and extremely decreased forces applied on the skier / snowboarder.

[0006] The purpose of the invention is to provide safer, healthier and more enjoyable experience of skiing and snowboarding and at the same time improve the performance possibilities of skis / snowboards.

Brief description of drawings

[0007] The invention provides the concept of isocentric skis and isocentric snowboard. It will be described in detail on the basis of embodiments, which are presented in the attached drawings showing:

Fig. 1 Top view and cross-section A-A of the left push-off leg ski

Fig. 2 Top view and cross-section A-A of the right push-off leg ski

Hg. 3 Top view and cross-section A-A of the left push-off leg snowboard

Fig. 4 Top view and cross-section A-A of the right push-off leg snowboard

Fig. 5 Different sidecut vertex positions (shown for right push-off leg ski)

Fig. 6 Linear angular sidecut under loading conditions

Fig. 7 Top view of the left push-off leg snowboard with different sidecut angles

Fig- 8 A pair of skis with different sidecut angles (for left push-off leg)

Fig. 9 Assembly of different ski pairs, concept of ski combination Detailed description of embodiments

[0008] Isocentric skis and isocentric snowboard have, instead of a radial sidecut, a linear angular sidecut (Fig. 1 to 4). The angle of the sidecut (Φ1) is lower than 180 degrees and is symmetric or asymmetric (according to the horizontal line). The sidecut vertex (5) is positioned in the middle of the ski / snowboard (waist) or closer to the tip or the tail of the ski / snowboard (Fig. 5). Sidecut vertex (5) is shaped as a point (sharp edge), an arc (soft edge), a straight line, a polygon, a polyline or any freeform shape that breaks a linear line into an angle. The width of the ski / snowboard linearly increases from the narrowest part, the sidecut vertex (5), towards the widest part of the tip (6) and the tail (7) (Fig 1 to 4). [0009] Under loading conditions the linear angular sidecut forms a triangular arc that defines the comparable sidecut radius - wide angles of the triangular arc are comparable with larger sidecut radii and narrow angles of the triangular arc are comparable with smaller sidecut radii. Skier / snowboarder can control the triangular arc (comparable sidecut radius) by controlling the force applied on the ski: the larger the force applied on the ski, the narrower the angle of the triangular arc (i.e. smaller comparable radius). The range of achievable comparable sidecut radii is very large. This enables turns with changeable radius without slipping or losing edge contact with the snow surface (as is the case with carving skis where the fixed sidecut radius defines and enforces the radius of the turn). Due to the decreased friction losses the achievable velocities are higher. At the same time the responsiveness of the ski / snowboard is higher and skiing / snowboarding more flexible and more easily manoeuvrable.

[0010] Linear angular sidecut grips the surface primarily with three points: a point on the front sidecut line (T1), a point on the rear sidecut line (T2) and a third, mobile point (T3) in between (Fig. 6). Positions of the front (T 1) and the rear (T2) points depend on the force applied on the ski, while the position of the third mobile point (T3) changes according to the skier's / snowboarder's balance point and is independent of the front (T1) and the rear point (T2) positions. Under loading conditions sidecut vertex (5) is pushed towards the snow surface which consequently pushes the points (T1) and (T2) towards the tip and tail respectively (Fig. 6). This extends the length of the effective edge, i.e. the length of the edge in contact with the snow surface, which in combination with variable angle of the triangular arc (i.e. comparable radius) reduces micro-vibrations (high-frequency / low amplitude); they are significantly lower in comparison with those of skis with radial sidecut. Because the sidecut does not grip the surface equally strong along the entire sidecut length, riding is more stable and results in fewer vibrations overall.

[0011] The three grip points of the linear angular sidecut enable continuous re-centring of the constantly moving centre of the turns, i.e. the isocentre. This enables a new way of skiing / snowboarding where the centre of the turns is not fixed by the sidecut radius but is continuously readjusted according to the skier's body movement. [0012] Linear angular sidecut decreases the centrifugal forces on the skier / snowboarder. In turns the force is transferred from the front half of the ski / snowboard to the vertex (5), where the force is further dissipated into the rear half of the ski / snowboard - crosswise from the left side to the right side and from the right side to the left side. Due to the smaller forces exhibited on the body, skiing / snowboarding is easier and at the same time more responsive and skilful. Smaller loading of the body prevents from injuries, damages and fatigue of joints and back (especially of the lumbar region). [0013] Linear angular sidecut promotes natural body movement: skiing / snowboarding is easier since the skier / snowboarder does not need to adapt his body movement to the fixed and often rigid properties of the ski / snowboard, but is due to the flexibility, responsiveness and balance of the isocentric skis / snowboard able to move more freely and naturally.

[0014] Characteristic of the isocentric skis and the isocentric snowboard is (i) sidecut shortened and extended differently on the left and the right side of the ski / snowboard or (ii) sidecut shifted differently on the left and the right side of the ski / snowboard. [0015] (i) Length of the sidecut on the left and the right side of the skis (Fig. 1 and 2) is determined with navigation arc (1), (4) that shortens the sidecut on the left and the right sides of the ski (inversely at the tip and the tail - when the left sidecut is shortened at the tip, the right sidecut is shortened at the tail and vice versa) and with a straight line (2), (3) that extends the sidecut on the opposite sides of the ski: when sidecut is shortened with the navigation arc at the tip (1), it is extended with a straight line at the tail (2); and when it is shortened with the navigation arc at the tail (4), it is extended with a straight line at the tip (3).

[0016] When the navigation arc at the tip (1) falls from left to right, it shortens the right sidecut (Fig. 1) and when it rises from left to right, it shortens the left sidecut (Fig. 2). When the navigation arc at the tail (4) falls from left to right, it shortens the left sidecut (Fig. 1) and when it rises from left to right, it shortens the right sidecut (Fig. 2).

[0017] The length of the sidecut on the left and the right side of the skis determines the style of skis: shorter sidecuts (i.e. longer navigation arcs) are suitable for shorter turns, while longer sidecuts (i.e. shorter navigation arcs) are suitable for longer turns. Navigation arcs can be shaped as circular arc, polyline, polygon, straight line or a free-form shape.

[0018] (ii) Vertex (5) is shifted from the default waist position towards the tip (5A) or the tail (5B) on one side of the snowboard, or is shifted in opposite directions (tip / tail) on the left and the right side of the snowboard (Fig. 3 and 4). When the vertex is shifted, the entire sidecut is shifted for an equivalent amount; thus the endpoints (6), (7) are equivalent^ shifted towards the tip (6A), (7A) or the tail (6B), (7B). With the shift of the vertex the line between the vertexes on the left and the right side of the snowboard is not horizontal, but forms an angle (Φ2) with the horizontal (the angle ranges from 0 to 90 degrees). This creates a third point of balance that provides additional stability to snowboarding, resulting in a smoother and straighter ride. The concept of different shift of vertex (5) on the left and the right side of the snowboard is applicable also to skis. [0019] Because the push-off leg is always stronger and more stable than the non-push-off leg, skiers / snowboarders ride the push-off leg turn using more force than the turn with the non-push-off leg. For the right-handed push-off leg is normally the left leg, while for the left-handed push-off leg is normally the right leg. The existing skis and snowboards are designed symmetrically for the left and the right side of the body - since less force is applied to the non-push-off leg ski, the turn with the non-push-off leg is different, which enforces unsymmetrical riding and establishes unnatural body balance. Different sidecut on the left and the right side of the ski / snowboard enables different loading of the left and the right ski: with the push-off leg larger force can be applied due to the extended rear sidecut line on the inner side of ski (at skiing the inner sidecut is normally more loaded than the outer sidecut, especially the rear part of the sidecut) and with the non-push-off leg lower force can be applied (to achieve the same result as with the push-off leg) due to the shortened rear sidecut line on the inner side of the ski. The result is equal (symmetrical) response of the left and the right ski regardless of the different loading of both skis - the skis nullify the effect of different strengths of the push-off and the non- push-off leg.

[0020] Adapted for different push-off legs there are two versions of the ski: (i) left push-off leg ski (Fig. 1), and (ii) right push-off leg ski (Fig. 2); and there are two versions of the snowboard: (i) left push-off leg snowboard (Fig. 3) and (ii) right push-off leg snowboard (Fig. 4). [0021] On the left push-off leg ski the right sidecut is shortened at the tip with the navigation arc (1) and is extended at the tail with a straight line (2); while the left sidecut is shortened at the tail with the navigation arc (4) and is extended at the tip with a straight line (3) (Fig. 1).

[0022] On the right push-off leg ski the right sidecut is shortened at the tail with the navigation arc (4) and is extended at the tip with a straight line (3); while the left sidecut is shortened at the tip with the navigation arc (1) and is extended at the tail with a straight line (2) (Fig. 2).

[0023] On the left push-off leg snowboard the vertex (5) is shifted towards the tip (5A) on the right side of the snowboard and towards the tail (5B) on the left side of the snowboard (Fig. 3). The sidecut angle on the left side of the snowboard is smaller or equal to the angle on the right side of the snowboard: Φ1 L≤ Φ1 R (Fig 7).

[0024] On the right push-off leg snowboard the vertex (5) is shifted towards the tail (5B) on the right side of the snowboard and towards the tip (5A) on the left side of the snowboard (Fig. 4). The sidecut angle on the right side of the snowboard is smaller or equal to the angle on the left side of the snowboard: Φ1 R < Φ1 L.

[0025] A pair of skis consists of two different skis with different sidecut angles: one for push-off leg (Φ1Ρ) and one for non-push-off leg (Φ1 ) (Fig. 8). Sidecut angle of the push- off leg ski (Φ1Ρ) is smaller or equal to the sidecut angle of the non-push-off leg ski (Φ1Ν): Φ1Ρ < Φ1Ν. Due to different sidecut angles tip-waist-tail geometry of push-off and non- push-off leg skis is different: it is wider for push-off leg and narrower for non-push-off leg. Skis differ in one geometry - width of tail, two geometries - widths of tail and tip, or in all three geometries - widths of tail, tip and waist. [0026] For people with equally strong left and right leg a pair of skis with equal sidecut angle for push-off and non-push-off leg skis is appropriate: Φ P = Φ1 N.

[0027] By combining two left push-off leg skis and two right push-off leg skis four different ski pairs can be assembled, which provides a new concept of ski use (Fig. 9). Currently, the skis available on the market are sold as indivisible pairs, while the isocentric skis will be available also as single skis where the user will choose his own pair.

[0028] Two right push-off leg skis (RR) and two left push-off leg skis (LL) enable assembly of four different ski pairs (RR), (LL), (RL) and (LR) and four different styles of skiing. Three individual skis enable assembly of three different ski pairs (RR), (RL), (LR) or (LL), (LR), (RL) and three different styles of skiing. Two different skis enable assembly of two different ski pairs for two different styles of skiing (RL), (LR). Two identical skis make an asymmetrical pair (RR) or (LL).

[0029] With a pair consisting of two left push-off leg skis (LL), the sidecut on the inner side of the skis is shortened at the tail for the right leg and at the tip for the left leg, while it is extended at the tip for the right leg and at the tail for the left leg (Fig. 9a). The sidecut on the outer side of skis is shortened at the tip for the right leg and at the tail for the left leg, while it is extended at the tail for the right leg and at the tip for the left leg. Skier skis primarily with the left leg.

[0030] With a pair consisting of two right push-off leg skis (RR), the sidecut on the inner side of skis is shortened at the tip for the right leg and at the tail for the left leg, while it is extended at the tail for the right leg and at the tip for the left leg (Fig. 9b). The sidecut on the outer side of skis is shortened at the tail for the right leg and at the tip for the left leg, while it is extended at the tip for the right leg and at the tail for the left leg. Skier skis primarily with the right leg. [0031] With a pair consisting of a left push-off leg ski and a right push-off leg ski (LR), the sidecut on the inner side of both skis is shortened at the tip and extended at the tail, while the sidecut on the outer side of both skis is shortened at the tail and extended at the tip (Fig. 9c). This combination has the properties of a pair of longer skis (giant slalom skis). [0032] With a pair consisting of a right push-off leg ski and a left push-off leg ski (RL), the sidecut on the inner side of both skis is shortened at the tail and extended at the tip; while the sidecut on the outer side of both skis is shortened at the tip and extended at the tail (Fig. 9d). This combination has the properties of a pair of shorter skis (slalom skis).

Claims

PATENT CLAIMS

1. Isocentric skis and isocentric snowboard (0) defined by a linear angular sidecut (instead of a radial sidecut) with the angle of the sidecut smaller than 180 degrees.

2. Isocentric skis and isocentric snowboard (0) according to claim 1 where a linear angular sidecut is symmetric or asymmetric (according to the horizontal line) and symmetric or asymmetric on the left and the right side of the ski / snowboard (according to the vertical line).

3. Isocentric skis and isocentric snowboard (0) according to claim 1 with the vertex (5) positioned in the middle or closer to the tip (6) or the tail (7) of the ski / snowboard - equally or differently on the left and the right side of the ski / snowboard.

4. Isocentric skis and isocentric snowboard (0) according to claim 1 where the sidecut vertex (5) is shaped as a point (sharp edge), an arc (soft edge), a straight line, a polygon, a polyline or any freeform shape that breaks a linear line into an angle.

5. Shortened and extended sidecut of isocentric skis and isocentric snowboard (0); length of the linear sidecut of the skis / snowboards is determined with the navigation arc (1), (4) that shortens the sidecut on the left and the right side of the ski / snowboard (inversely at the tip and the tail) and with a straight line (2), (3) that extends the sidecut on the opposite sides.

6. There are two versions of the isocentric skis and isocentric snowboard (0) - one for left push-off leg and one for right push-off leg:

- on the ski for left push-off leg (L) the right sidecut is shortened at the tip with the navigation arc (1) and extended at the tail with a straight line (2), while the left sidecut is shortened at the tail with the navigation arc (4) and extended at the tip with a straight line

- on the ski for right push-off leg (R) the right sidecut is shortened at the tail with the navigation arc (4) and extended at the tip with a straight line (3), while the left sidecut is shortened at the tip with the navigation arc (1) and extended at the tail with a straight line (2),

- on the snowboard for left push-off leg the vertex (5) is shifted towards the tip (5A) on the right side of the snowboard and towards the tail (5B) on the left side of the snowboard, and the angle of the sidecut on the left side of the snowboard (Φ1Ι_) is smaller or equal to the angle on the right side (<t>1R),

- on the snowboard for right push-off leg the vertex (5) is shifted towards the tail (5B) on the right side of the snowboard and towards the tip (5A) on the left side of the snowboard, and the angle of the sidecut on the right side of the snowboard (01R), is smaller or equal to the angle on the left side (Φ1 L).

7. Use of ski pairs consisting of two isocentric skis (0) with different sidecut angles; sidecut angle for push-off leg ski (Φ1Ρ) is smaller or equal to sidecut angle for non-push-off leg ski (Φ1Ν).

8. Use of four different ski pair combinations for four different styles of skiing consisting of isocentric skis (0) for right push-off leg (R) and left push-off leg (L):

- two left push-off leg skis (LL) - left-push-off leg natural skiing,

- two right push-off leg skis (RR) - right-push-off leg natural skiing,

- left push-off leg ski and right push-off leg ski (LR) - giant slalom,

- right push-off leg ski and left push-off leg ski (RL) - slalom.