US20030006584A1

US20030006584A1 - Snow skis having asymmetrical edges

Info

Publication number: US20030006584A1
Application number: US10/155,756
Authority: US
Inventors: Scott Carlson
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-09
Filing date: 2002-05-24
Publication date: 2003-01-09

Abstract

Snow skis having asymmetrical edges to make turning easier while telemark or alpine skiing. Each ski has concave, curved lateral edges. These lateral edges are asymmetrical, in that the medial edge of each ski is substantially longer than its outer edge. In addition, the point of maximum side cut on the outer edge is adjacent to the toe area of the skiers boot, while the point of maximum side cut on the medial edge is adjacent to the middle of the ski boot to facilitate easier turns while telemark skiing.

Description

RELATED APPLICATION

The present application is a continuation-in-part of co-pending U.S. patent application Ser. No. 09/626,318, filed Jul. 25, 2000, titled SNOW SKIS HAVING ASYMMETRICAL EDGES, which will issue on May 28, 2002, and claims the benefit of U.S. Provisional Patent Application No. 60/152,981, titled TELEMARK SKI, filed on Sep. 9, 1999.[0001]

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of snow skis. More specifically, the present invention discloses snow skis having asymmetrical lateral edges.

2. Conventional Types of Skis

A variety of types of skis are currently in use. The present invention is intended primarily for telemark skiing, although it can be readily adapted for other types of skis, including the following types of skis in common use:

The “alpine ski”, or fixed hell ski, is characterized by its utilization rather than its design. The binding by which a skier's boot is attached to the ski secures both the toe and heel of the ski boot to the ski simultaneously. This method of binding characterizes the use of this ski as “alpine.” In alpine skiing, both skis are generally maintained parallel to one another. The skier turns by shifting weight to the medial edge of the outside ski (i.e., the ski farther from the center of the circle describing the turn).

The “telemark ski”, or free heel ski, is similarly characterized by its utilization rather than its design. The binding by which the skier's boot is attached to the ski causes only the toe component of the ski boot to be fixed to the ski, while leaving the heel free to rise off the ski. Other than the binding, the ski is essentially the same as an alpine ski. Turning in telemark skiing is quite different than in alpine skiing. The skier positions the inside ski (i.e., the ski closer to the center of the circle describing the turn) behind the outside ski, so that the heel of the inside boot is raised off the inside ski. Any pressure applied by the skier to the inside ski is exerted via the toe area of the boot (i.e., the general area between the ball of the skier's foot to the lip of the boot. In contrast, the outside boot remains flat against the outside ski, so that pressure is exerted on the ski over the entire area of the ski boot. When the inside boot is raised and the outside boot remains flat, a “telemark posture” is attained.

In telemark skiing, the points of applied pressure (resulting from the skier's application of weight and resulting additional forces) exist at different locations along the longitudinal axes of each ski. The inside ski (i.e., the ski closer to the center of the circle describing the turn) receives the application of pressure at the toe area of the attached boot. The outside ski receives the application of pressure along the entire bottom of the boot's sole.

The “active edge” refers to the edge of each ski closer to the center of the turn being executed, i.e., the inside edge of the turn. By tilting the ski and applying pressure on the active edge, the active edge of each ski engages the underlying snow surface causing the ski to turn.

The “cross-country ski” is similar to the telemark ski, except that it is designed for flatter terrain. Cross-country skis tend to be narrower and lighter than telemark skis.

The “randonée ski” is a hybrid of free heel and fixed heel skis, wherein the heel binding can either be fixed or free at the option of the skier.

3. Prior Art

The prior art in the field includes the following:



Inventor	Pat. No.	Issue Date

Staufer	4,377,297	Mar. 22, 1983
Meatto et al.	4,688,821	Aug. 25, 1987
Gauer	4,705,291	Nov. 10, 1987
Fagot	4,971,350	Nov. 20, 1990
Floreani	5,301,965	Apr. 12, 1994
Petkov	5,405,161	Apr. 11, 1995
Nelson	5,603,522	Feb. 18, 1997
Karlsen	5,876,056	Mar. 2, 1999
Richmond	4,895,388	Jan. 23, 1990

“Open the Toy Box,” Skiing Trade News, page 20 (January, 1997)

“All Aboard! Ski and Snowboard Design Rides the Boom into the Backcountry,” Seattle Post-Intelligencer, Getaways, page 8 (Oct. 23, 1997)“Arc Angles: We Test Some Skis You Can Bank On,” Skiing, page 108 (vol. 49, no. 4, December 1997)

“Inbounds Adventure,” Skiing, page 124 (vol. 51, no. 1, September 1998)“A Slice of Heaven,” Skiing, page 156 (vol. 51, no. 3, November 1998)

The article from Skiing Trade News mentions and shows a picture of the “Radarc” skis introduced by Fischer GmBH of Austria. The articles from the Seattle Post-Intelligencer and Skiing also describe the Fischer Radarc skis. The Fischer Radarc skis have asymmetrical side cuts with the longer edges on the outside of the skis, which is opposite from the present invention. The side cut on the outer edge is shifted farther back toward the tail of the ski than the side cut on the inside edge. This arrangement is also backward from the present invention. It appears that the Radarc ski is intended for a specialized style of alpine skiing known as “carving”, in which the skier's legs are spread apart and turns are made by exerting substantially equal force on the active edges of both skis. The active edges make substantially concentric circles for both skis. Therefore, since the outside ski turns with a larger radius than the inside ski when carving, it may be advantageous for the medial edge of the outside ski to have a larger radius than the lateral edge of the inside ski. However, it should be expressly understood that the Radarc ski addresses a completely different problem and teaches away from the present invention.

Meatto et al. disclose asymmetrical alpine skis with offset boot platforms. The medial edges of the skis have side cuts but the outer edges are substantially straight.

Fagot discloses an alpine ski with a symmetrical bottom surface, but having asymmetrical, inwardly sloping sidewalls.

Gauer discloses a short symmetrical alpine ski that is convex from front to rear, and also convex from side to side.

Floreani, Nelson, Karlsen, Petkov, and Richmond disclose other examples of symmetrical skis of various types.

Staufer discloses a symmetrical alpine ski with a series of side cuts along both edges.

In addition to the prior art discussed above, several types of asymmetrical snowboards have been marketed in the past. Snowboard bindings typically hold the rider's feet at a diagonal angle with respect the snowboard. As a result, the center of pressure shifts slightly forward or rearward as the rider transfers his weight to the right or left edges to turn the snowboard. Some snowboards compensate for this axial shift in the center of pressure by placing the point of maximum side cut on the right side of the board further forward than on the left side, for a right-footed snowboarder. This would be reversed for a left-footed snowboarder.

4. Statement of the Problem

Properly designed skis must accommodate a number of concerns in today's highly competitive market. It is particularly important that the skier should be able to execute turns without undue effort, and that the skis should be stable and easy to control. The prior art listed above has several shortcomings, particularly with regard to telemark skiing:

(a) Asymmetrical Edge Pressure Problem With Existing Snow Skis. In the telemark posture, it is difficult to apply a large amount of pressure on the active edge of the inside ski, because the knee over that ski is bent and contact with that ski is only made by the toe area of the boot. Since there is less pressure on the active edge of the inside ski, it is more difficult to turn that ski. However, in the telemark posture, it is comfortable and easy to apply pressure on the active edge of the outside ski, because the knee over that ski is straighter and the contact with the ski is made by the entire bottom of the boot. Since there is more pressure on the active edge of the outside ski, it is easier to turn that ski.

In the utilization of existing telemark ski equipment in the telemark posture, the amount of pressure on the active edge of the inside ski is significantly less than the amount of pressure on the active edge of the outside ski, owing to the different locations of application of pressure for each of the two skis when a telemark posture is employed. In order to best turn both skis together, it would be ideal if the pressure on each active edge were close to equal. The problem with existing skis is that their design results in a substantial disparity of pressure on the active edges.

(b) The Center of Pressure Problem With Existing Snow Skis. As previously discussed, turns are accomplished on skis by applying pressure on the active edge. The active edge turns the ski by virtue of its shape, which is curved inward toward the center of the ski, as shown for example in FIGS. 4 and 5. Since this curvature is achieved by effectively cutting out the side of the ski, it is known in the ski industry as “side cut”. The point along the edge having the greatest side cut can be referred to as “maximum side cut.” Maximum side cut can also be defined as the point along the edge that is furthest from an imaginary straight line running between the two ends of the edge.

The center of pressure on a ski is the point underneath the boot denoting the center of downward pressure from the skier onto the ski. On any snow ski, there is a particular point either at maximum side cut, or very close to it, where it is best to have the center of pressure located for optimal turning. Ski manufacturers typically mark that point “boot center”, and bindings are mounted on the ski so that the center of pressure is at that point.

Existing snow skis are constructed so that maximum side cut on each edge is located at the same point along the length of the ski on each side. This symmetrical arrangement of maximum side cuts makes sense for alpine skiing, where the boot is fixed in one place. In telemark skiing, due to the telemark posture, there are two different centers of pressure on each ski. One center of pressure is under the middle of the boot sole when the ski is the outside ski and the boot is resting flat on the ski. However, when the ski is the inside ski, the skier's knee is bent so that the heel rises, and the center of pressure shifts forward and is located under the toe area of the boot. Symmetrical maximum side cuts on existing skis are not well-suited for telemark skiing because they are designed as if there were only one center of pressure. This flaw results in the telemark skier's application of pressure in a location on the inside ski that is not ideal for the physical properties of the curved edge.

(c) Proportional Length Problem With Existing Telemark Skis. Skis are typically designed with predetermined proportions of the ski in front and behind the center of pressure exerted by the skier's boot. For example, many conventional skis are optimal if have approximately 55% of their length is in front of, and approximately 45% is behind the center of pressure. In telemark skiing, the center of pressure for the inside ski shifts forward when turning, as previously discussed. This also shifts the proportion of the ski in front and behind the center of pressure, resulting in less than optimal performance for that ski, and causing a disparity with the proportional lengths of the other ski.

5. Solution to the Problem

The present invention addresses the edge pressure problem discussed above by shortening the active edge of the inside ski. By reducing the length of the active edge receiving less pressure, the lineal force along that active edge is increased so it is brought closer to parity with the lineal force on the active edge of the outside ski. This leads to increased facility and fluidity while turning. In other words, the present invention makes it easier to turn the inside ski by shortening the active edge of that ski.

The present invention also solves the problem of having two centers of pressure in telemark skiing by locating the point of maximum side cut at a point along each edge corresponding to the location of the center of pressure when that edge is the active edge. By locating the point of maximum side cut for each active edge according to that edge's center of pressure, the present invention increases the maneuverability and responsiveness of the skis.

The present invention also solves the proportional length problem associated with conventional telemark skis by using different medial and outer edge lengths.

SUMMARY OF THE INVENTION

This invention provides snow skis having asymmetrical edges to make turning easier. In particular, each ski has concave, curved lateral edges, whereby the medial edge of each ski is substantially longer than its outer edge. In addition, the points of maximum side cut on the ski edges can be asymmetrical with one in front of the other. The point of maximum side cut on the outer edge is generally adjacent to the toe area of skier's boot, while the point of maximum side cut on the medial edge is generally adjacent to the middle of the ski boot to facilitate easier turns while telemark skiing. These and other advantages, features, and objects of the present invention will be more readily understood in view of the following detailed description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more readily understood in conjunction with the accompanying drawings, in which: [0037]
FIG. 1 is a top plan view of a pair of telemark skis consistent with the present invention. [0038]
FIG. 2A is a side elevational view of the [0039] right ski 200 corresponding to FIG. 1.
FIG. 2B is a side elevational view of the [0040] left ski 100 corresponding to FIG. 1.
FIG. 3 is a bottom plan view of the [0041] right ski 200 corresponding to FIG. 1.
FIG. 4 is a top plan view of a pair of telemark skis in a right turn. [0042]
FIG. 5 is a top plan view of a pair of telemark skis in a left turn. [0043]
FIG. 6 is a front perspective view of a right alpine ski embodying the present invention.[0044]

DETAILED DESCRIPTION OF THE INVENTION

Turning to FIG. 1, a top plan view is presented of a pair of [0045] telemark skis 100, 200 embodying the present invention. FIG. 2A is a corresponding side elevational view and FIG. 3 is a corresponding bottom plan view of the right ski 200. FIG. 2B is a side elevational view of the left ski 100 in FIG. 1. Each ski 100, 200 has a front tip 101, 201 and bindings 150, 250 for securing the skier's boots to the skis. Each ski 100, 200 also has a left lateral edge 110, 210 and an opposing right lateral edge 120, 220, respectively.
In the preferred embodiment of the present invention, both left lateral edges of each ski have concave, curved shapes. This is normally referred to as side cut. Although the [0046] left ski 100 is typically a mirror image of the right ski 200, it is important to note that these lateral edges are not symmetrical for each ski. In particular, the left edge 110 of the left ski 100 has a length, L_O, that is substantially shorter than the length, L₁, of its right edge 120. Similarly, the left edge 210 of the right ski 200 has a length substantially longer than that of its right edge 220. Generally, the medial edges 120, 210 of both skis 100, 200 have the same length, L₁, and the outer edges 110, 220 of both skis have the same length, L_O, which is substantially shorter than L₁. In the preferred embodiment of the present invention, the outer edges 110 and 220 have a length, L_O, that is approximately 2 to 14 inches shorter than the length, L₁, of the medial edges 120, 210.
It should be expressly understood that the lateral edges of the [0047] skis 110, 120, 210, and 220 are determined not by the part of the ski that has metal edges, but instead by the curved (i.e., side cut) portion of the side of the ski used for turning. The ends of the lateral edges 110, 120, 210, and 220 are determined by the point at which the side of the ski substantially departs from a concave curve and turns back inward toward the opposing lateral edge. The radius of curvature of the outer edges 110, 220 can either be equal or less than the radius of curvature of the medial edges 120, 210. In contrast, the length of each edge is measured along a line extending parallel to the longitudinal axis of the ski (i.e., L₁, or L_O) as shown in FIG. 1. In addition, it should be noted that an edge does not necessary have a uniform curvature over its entire length and could have relatively straight portions, particularly near the area of maximum side cut.
The [0048] tips 101, 201 of the skis are typically symmetrical about the longitudinal axis of each ski for greater stability, although asymmetrical tips are possible. As shown in the side elevational views provided in FIGS. 2A and 2B, the tips 101 and 201 curve upward to help the skis ride over the surface of the snow. In the preferred embodiment, both the left and right medial edges of the ski begin at substantially the same distance behind the tip of the ski, as illustrated in FIG. 1. However, the longer length of the medial edge 120, 210 results in an asymmetrical tail section 102, 202 for each ski. One possible configuration of the tail section 102, 202, depicted in FIGS. 1 and 3, extends diagonally inward from the trailing end of the outer edge 110, 220 toward the trailing end of the medial edge 120, 210 for each ski. Alternatively, the tail section 102, 202 could be rounded or have any other suitable contour connecting the trailing end of the medial edge 120, 210 with the trailing end of the outer edge 110, 220 of the ski. Each ski typically has a tail section 102, 202 that is a mirror image of the other ski's tail section.
When the present invention is used in telemark skis as shown in FIGS. 1, 4 and [0049] 5, the points of maximum side cut on the medial and outer edges relative to the binding 150, 250 and the skier's boot 160, 260 are significantly different. Please note that the point of maximum side cut 115 on the left edge 110 of the left ski 100 is generally adjacent to the toe area of the skier's left boot 160. Similarly, the point of maximum side cut 225 on the right edge 220 of the right ski 200 is generally aligned with the toe area of the skier's right boot 260. In contrast, the point of maximum side cut 125 on the right edge 120 of the left ski 100 is adjacent to the middle of the skier's left boot 160, and the point of maximum side cut 215 on the left edge 210 of the right ski 200 is adjacent to the middle of the skier's right boot 260. Thus, the locations of the points of maximum side cut correspond to the shifting of the center of pressure exerted by the telemark skier's boot 160, 260 while turning, as will be discussed in greater detail below. The distance between these points of maximum side cut as measured along the longitudinal axis of the ski is in the range of approximately 1 to 10 inches in the preferred embodiment of the present invention.
FIG. 4 is a top plan view of a pair of [0050] telemark skis 100, 200 in a right turn, and FIG. 5 is a corresponding top plan view of a left turn. To execute a turn, the skier positions the inside ski behind the outside ski, so that the heel of the inside boot is raised off the inside ski. Any pressure applied by the skier to the inside ski is exerted via the toe area of the boot. In contrast, the outside boot remains flat against the outside ski, so that pressure is exerted over the entire area of the ski boot. The active or turning edges are the medial edge of the outside ski and the outer edge of the inside ski, as shown in bold lines in FIGS. 4 and 5.
The present invention recognizes and accommodates this difference in the centers of pressure for the inside and outside skis by aligning the point of maximum side cut [0051] 115, 225 on the outer edge of the inside ski with the toe area of the inside boot, while the point of maximum side cut 125, 215 on the medial edge of the outside ski is adjacent to the middle of the outside boot. In other words, the point of maximum side cut 115, 225 on the outer edge of each ski is in front (i.e., closer to the ski tip) of the point of maximum side cut 125, 215 on its medial edge. This configuration enables the center of pressure for each ski to remain aligned with the point of maximum side cut (i.e., center of curvature) for the active or turning edge for that ski, thereby providing greater stability and ease of turning.
More specifically, please consider the right turn illustrated in FIG. 4. The [0052] right ski 200 is the inside ski, while the left ski 100 is the outside ski in the turn. The skier positions the right ski 200 behind the left ski 100, so that the right knee is bent and the heel of the right boot is raised off the right ski 200. The active edges are the right edges 120, 220 of both skis 100, 200. Any pressure applied by the skier to the right ski 200 is exerted via the toe area of the boot, which is adjacent to the point of maximum side cut 225 on the right edge 220 of the right ski 200. In contrast, the left boot remains flat against the left ski 100, so that pressure is exerted over the entire area of the left ski boot. The point of maximum side cut 125 on the right edge 120 of the left ski 100 is adjacent to the middle of the skier's left boot.
Similarly, in the left turn depicted in FIG. 5, the skier positions the [0053] left ski 100 behind the right ski 200, so that the left knee is bent and the heel of the left boot is raised off the left ski 100. The right boot remains flat against the right ski 200. The active edges are the left edges 110, 210 of both skis 100, 200. The point of maximum side cut 115 on the left edge 110 of the left ski 100 is adjacent to the toe area of a skier's left boot. In contrast, the point of maximum side cut 215 on the left edge 210 of the right ski 200 is adjacent to the middle of the skier's right boot.
FIGS. 1 through 5 illustrate the present invention used in telemark skis. It should be expressly understood that the present invention could be applied to other types of skis, such as alpine, randonee, and cross-country skis. For example, FIG. 6 is a front perspective view of a [0054] right alpine ski 300 embodying that aspect of the present invention relating to different edge lengths. In alpine skiing, the inside or medial edge of the outside ski is used for turning. For example, in a left turn, pressure is applied to the left edge of the right ski. The ideal in alpine skiing is to place nearly all of the skier's weight and pressure on that active edge. In a left turn, the right edge of the right ski is not used. By reducing the length of this superfluous edge, the present invention causes the skis to be lighter. Lighter skis are easier to maneuver and quicker to place on edge.
In addition, the outer edge of the inside ski (e.g., the left edge of the left ski in a left turn) must make a tighter-radius turn if the inside ski is to remain parallel with the outside ski. This is made more difficult by the fact that only a minimal amount of pressure is normally applied to the inside ski. Here again, the present invention addresses these concerns by reducing the length of the outer edge of the inside ski, thereby increasing the lineal force on that edge, making it easier to perform shorter-radius turns. [0055]
The above disclosure sets forth a number of embodiments of the present invention. Other arrangements or embodiments, not precisely set forth, could be practiced under the teachings of the present invention and as set forth in the following claims. [0056]
The intended purpose of the described design includes all types of snow skis, including but not limited to, the types described below: [0057]
Snow Skis [0058]
The “alpine ski”, or fixed heel ski, is characterized by its utilization rather than by its design. The binding equipment by which a skier's boot is attached to the device secures both the toe and heel components of a ski boot to the device simultaneously. This method of binding characterizes the use of this ski as “alpine”. [0059]
The “telemark ski”, or free heel ski, is similarly characterized by its utilization rather than by its design. The binding equipment by which a skier's boot is attached to the device secures only the toe component of a ski boot to the device, leaving the heel component free to rise off of the device. This method of binding characterizes the use of this ski as “telemark”. [0060]
The “randonée ski” is a hybrid of “free heel” and “fixed heel”, wherein the operation of the binding as free or fixed with respect to the heel is selectable at the option of the skier. [0061]
The “snow blade” or “ski board” is a shorter version of the alpine ski often used in half pipes and for performing tricks. [0062]
Existing ski designs do not account for the different amounts of pressure applied to each ski. In both telemark and alpine turns, the majority of the skier's weight is on the downhill ski. The reason for this unequal pressure in telemark skiing is primarily due to the asymmetrical body position of the skier, which makes it more difficult to pressure the uphill ski. The unequal pressuring of the skis in alpine skiing primarily results from centrifugal force, which throws most of the skier's weight onto the downhill ski lying on the outside of the turn being made. [0063]
Skis turn differently according to the amount of pressure applied on the turning edge. The unequal forces on each ski cause them to track differently, forcing the skier to exert extra effort to make them turn together. Skiers on existing designs pressure two virtually identical edges with extremely different amounts of pressure and expect both skis to perform in the same manner. [0064]
The inside edge of each ski is used as the turning edge on the downhill ski. The outside edge of each ski is used as the turning edge of the uphill ski. Since the uphill ski has much less pressure applied to it, the correct way to design a ski is to have the outside edge shorter than the inside edge. This increases the lineal pressure on the outside edge so that the lineal pressure on each turning edge is approximately equal. [0065]
There is only one ski that may have a shorter outside edge and that's the “Bigfoot” (Moelg). It appears from examining an actual Bigfoot ski, that the outside edge is shortened in the tip area by less than an inch. The ski has been designed to resemble a human foot in appearance, and the shape of the foot necessitated a slightly shorter outside edge. In order to address the unequal pressure problem, the outside edge must be shortened much more than an inch. Under normal conditions, a skier can detect a difference when the outside edge is shortened a about of 3 inches. No existing ski design has addressed the unequal pressure applied to skis through shortening the outside edge. [0066]
Telemark skiing also has another related problem. Although the uphill skis pressured less as discussed above, it is also pressured in a different location. When the skier raises his heel to pressure the outside edge of the uphill ski, the center of downward pressure on the ski shifts about 5″ forward. Although it may be preferable in alpine as well, it is necessary to shorten the outside edge in the tail area for telemarking. Presently, no skis have shorter outside edges in this manner. [0067]
The present invention makes skiing easier by causing the uphill ski to perform better than it does on existing designs. Ideally, a skier would pressure each ski in the same place with the same amount of pressure. Because this is never the case, it is best to design the skis asymmetrically so that the skis equalize the unequal forces applied by the skier. The present invention accomplishes this primarily by shortening the outside edge. [0068]
Shortening the turning edge (outside edge) of the uphill ski causes the lineal pressure (i.e. pressure per running inch) along that edge to increase and equal that of the turning edge of the downhill ski. By shortening that edge the correct amount, a minimum of effort is required to cause both skis to turn in an identical manner. For any given amount of downward pressure applied to the uphill ski, performance on that ski is improved according to the extent to which the turning edge is shortened. Note: It may be preferable to shorten the outside edge a different amount than what is necessary to make the lineal pressures equal, due to a preferred turn technique or style, skier type, snow conditions, etc. Similarly, it may be decided to shorten the edge the amount necessary to achieve a particular proportion of the edge in front of and behind the center of pressure (i.e. 55/45, 60/40, 85/15, etc.) [0069]
FIG. 7 shows a [0070] right ski 700 having edge ending points A, B, C, and D; and edge lengths L1 and L2. It will typically be advantageous to make L1 shorter than L2, because the outside edge receives less pressure than the inside edge. One way to design the ski is to shorten the outside edge the amount necessary to cause the lineal pressure on that edge to equal the lineal pressure on the inside edge of the opposite ski in a typical turn. By equalizing the lineal pressure on the turning edges, the skis will perform in symmetry without any adjustment by the skier.
There is presently electronic equipment that measures the amount of pressure on each foot in a turn, so that the outside edge may be shortened according to the average skier, or skier type, or even custom designed for an individual skier's form. The goal is to reach lineal pressure equilibrium on the turning edges. [0071]
As shown in FIG. 1, it will typically be advantageous to shorten the outside edge in the tail area so that rearward ending point of the outside edge is in front of the rearward ending point of the inside edge. This is shown in FIG. 1 by B and D, with B positioned in front of D along the ski. To allow straight tracking when the ski is flat on the snow it is easiest if points A and D are substantially planar, however, as shown by [0072] skis 1000 and 1100 in FIGS. 10 and 11, that is not necessary. It may be advantageous to shorten the outside edge in the tip as well, particularly for alpine skiing.
In telemark skiing, where the center of pressure on the outside edge is in front of that of the inside edge, it will typically be advantageous to design the ski so that distance from the rearward ending point of the outside edge to the forward ending point of the inside edge, is less than the distance from the rearward ending point of the inside edge to the forward ending point of the outside edge. This is shown by [0073] ski 800 in FIG. 8, where L1 is the length from B to C and L2 is the length from D to A, whereby L1 is shorter than L2. This causes the outside edge to be shifted forward, correctly adjusting it for the forward shift in the center of pressure in telemarking and possibly alpine skiing. It is not even necessary to shorten the edge for this shift to yield a benefit. For example, FIG. 11 shows ski 1100 having equal edge lengths (L1=L2), but the distance from B to C is less than the distance from D to A.
FIG. 9 shows a [0074] ski 900 with a couple of other possible features. The points of maximum sidecut can be offset to be located at the centers of pressure where the skier actually applies pressure to the ski. For example, the point of maximum sidecut on the outside edge can be located adjacent to the toe area of the boot, whereas max sidecut on the inside edge can be located adjacent to the center of the boot. This is particularly advantageous for telemark skiing where the center of pressure shifts about five inches forward on the outside edge.
Another thing shown in FIG. 9 is that the outside edge can be shortened the amount necessary to cause a particular proportion of edge lengths to occur. For example, in FIG. 9 the outside edge is shortened so that approximately 55% of the edge length is in front of each center of pressure and approximately 45% of the edge length is behind each center of pressure. It is generally thought that 55/45 yields the greatest stability. With existing designs, when the skier's weight shifts forward onto the outside edge, the proportion of edge length in front of and behind the center of pressure changes, leading to suboptimal performance on one ski in every turn. [0075]
FIGS. 10 and 11 show that A and C need not be planar. FIG. 11 also shows that the outside edge need not be any shorter than the inside edge. [0076]
FIG. 12 shows that any of these modifications can be applied to a [0077] ski 1200 without any shift in the points of maximum sidecut. This could be particularly advantageous for alpine skiing, where the center of pressure may stay at the same location along the length of the ski. More research needs to be done to determine if it stays in the same place or shifts as it does in telemark. All of the other diagrams happen to be drawn with shifted max sidecuts, but FIG. 12 represents that they all could be drawn and designed without shifted max sidecuts. In addition, all of the drawings show one ski, but they are equally representative of pairs of skis having the same characteristics.
The edge of the ski is intended to have a broad meaning consistent with the following. Each edge is substantially concave, whereas the ski itself may have any type of camber, such as ordinary camber, double camber, asymmetrical camber, or reverse camber. One definition of edge line has been explained above. Another possible definition for measuring edge length is measuring the length of the edge that is in contact with the snow in a turn. The area not touching the snow that is raised should not be measured, such as the upturn at the tip and the kick at the tail. Still another possible definition for measuring edge length is the ending points of the edge are determined by placing the ski on a hard flat planar surface and tilting it about 45 degrees onto the edge so that the edge makes contact near the tip and near the tail. The forward ending point is determined by moving rearward from the tip and locating the first point along the edge in contact with the plane. The rearward ending point is determined by moving forward from the tail and locating the first point along the edge in contact with the plane. For skis having reverse camber, it may be necessary to tilt beyond 45 degrees to make contact on the edge near the tip and the tail. The length of the edge is a straight line connecting the forward and rearward ending points of the edge. [0078]
The sidecut radii can be the same or different on each edge. The sidecut itself can be an arc or any other substantially concave shape, including what is referred to as parabolic. The sidecut can have any number of straight sections and any number of points of maximum sidecut. For example, when considering the “point of maximum” sidecut, it is understood that on many skis it may be better referred to as the “zone of maximum sidecut”, whereby it is possible to design a ski such that the middle of the general zone of maximum sidecut on the outside edge is located in front of the middle of the general zone of maximum sidecut on inside edge. [0079]

Claims

I claim:

1. A snow ski to be worn primarily on a ski boot, said snow ski comprising:

a concave, curved, outer edge; and

a concave, curved, medial edge having a length substantially longer than said outer edge.