Ski boot providing longitudinal torsion

A ski boot comprises an essentially stiff outer boot and a soft inner boot or inner lining for receiving the foot of a skier. The sole of the outer boot is made of an essentially rigid material, preferably plastics, comprising an elastic zone in the metatarsal region of the sole. The elastic zone divides the sole into front and rear sole portions. An intermediate upper shell portion is provided between the front and rear shell portions of the outer boot, which is designed such that front and rear shell portions are pivotable with respect to each other. The heel portion and rear sole portion are designed to be in an essentially rigid relationship such that a maximum force can be applied to the elastic zone of the boot. When the skier leans forward the front and rear shell portions pivot relative to each other. Due to the attachment of the lower leg to the rigid spoiler shaft, the ankle of the skier is braced securely to not flex or bend and the center of gravity of the skier can therefore remain in its most favored and athletically efficient position.

This application is the U.S. national phase of international application PCT/US01/16768, filed May 23, 2001, which designate the U.S., the entire contents of which is hereby incorporated by reference

FIELD OF THE INVENTION

The present invention relates to a ski boot that allows bending about a transverse axis, and torsion of the rear boot portion with respect to the front boot portion about the longitudinal boot axis.

PRIOR ART

German patent DE-OS-3343077 discloses a sole for a sports shoe, e.g. ski boot, which becomes stiff upon exertion of an external force. The upper shell of the ski boot should be construed such that a force exerted by the lower leg can be directed via the shaft, ankle and heel portions into the ski. However, as to the technical features of the upper shell the mentioned DE-OS-3343077 is silent.

U.S. Pat. No. 5,746,016 discloses a ski boot with pivotable toe cap and shaft. The toe is designed to be movable during walking, but fixed during skiing. For this reason the upper shell comprises a transversal opening with a cover. A tongue integral with the cover extends below the shell. The tongue can be blocked by means of a lock biased with a spring. In the blocked position, which is selected for skiing, pivoting of the toe cap is not possible. For skiing the shaft as well as the toe cap are stiff.

WO-A-91/16957 relates to an improved set comprising a ski, a ski boot, ski binding and a fulcrum element. WO-A-91/16957 proposes to use a ski boot wherein the toe cap is pivotable with respect to the rest of the boot. In particular, the toe cap is connected to the rear part of the boot by means of a hinge. The fulcrum element is located along a central section of the ski between the front and the rear bindings. When the ski boot flexes or pivots, force is directly applied via the fulcrum element to a central section of the ski to cause the central section to bow under such force.

In recent times, telemark skiing has experienced a renaissance. As to the equipment, telemark skiing differs from downhill skiing in the ski bindings and boots used. In contrast to a downhill ski binding the telemark ski binding has no fixed heel binding, but allows lifting the heel portion so that the rear sole portion (17) is almost at 90° to the ski and the knee of the skier can touch the ski in front of the binding. Consequently, the telemark ski boot must have a very flexible and soft sole which has essentially no tendency to rebound. In addition, the ankle in the telemark boot is not fixed but moves forward and backward when the heel portion is lifted. A telemark boot is therefore very difficult to use when the heel is fixed to the ski.

OBJECT OF THE INVENTION

It is therefore an object of the present invention to provide a novel ski boot which reduces stress to the skier's anatomy and allows a better control of the ski. Another object is to provide a ski boot which allows the skier to maintain a more natural position when skiing. A further object is to provide a ski boot which allows the skier to direct more force into the ski than with conventional boots. Yet a further object is for the ski boot sole to more closely mimic the bending and dynamic response characteristics of the ski directly under the ski boot sole. Yet another object is for the ski boot sole to absorb strain forces effectively and enable the skier to more functionally use the proprioceptive nerve endings in the soles of the feet to improve sensitivity for better balance and control. According to the invention a ski boot according to the descriptive or designating part of claim1is characterized in thatthe sole of the outer boot is made of an essentially rigid material, preferably plastics, comprising an elastic zone in the metatarsal region of the sole dividing the sole into front and rear sole portions;an intermediate upper shell portion is provided between the front and rear shell portions of the outer boot, which is designed such that front and rear shell portions are bendable with respect to each other;the heel portion, shaft, and rear sole portion (17) are designed to be in an essentially rigid relationship;the attaching or fixing means comprising at least an ankle fixing and attaching means (39) for extending around the ankle region and fixing the ankle and heel into in the rear heel portion, anda lower leg fixing and attaching means for extending around the shinbone-and inner boot shaft and effectively coupling the lower leg to the rear shell shaft, in particular spoiler of the rear shell shaft with little or no play.

By the novel design of the ski boot a force triangle is created that directs all the forces exercised by the skier directly to the elastic bending portion of the sole under the metatarsal area of the foot. The elastic bending portion of the sole is activated in turn by the vibrations and bending activity of the ski. The elasticity of the sole can be designed to respond according to a specific dynamic response that complements the ski's bending and torsional dynamic response qualities. Another advantage of the novel ski boot is that due to the attachment of the lower leg to the rigid spoiler shaft, the ankle of the skier is braced securely to not flex or bend and the center of gravity of the skier can therefore remain in its most favored and athletically efficient position.

Advantageously, the shaft, heel and rear sole portions of the outer boot are made of essentially non-flexible or unyielding plastics such that the heel portion, shaft and rear sole portion form a rigid or essentially non-flexible assembly. This allows the user to apply more force and more directly into the ski than with conventional boots with pliable or yielding shafts. The shaft and spoiler supports the ankle and the lower leg in its strongest position with the stiffest possible support, while the sole bends and rebounds under the forefoot. When the ankle does not have to flex then the knees do not have to flex more than minimally either and therefore also remain in the strongest and most stable position, which can be demonstrated in x-ray motion video. In essence the invention moves the important flex elements from the ankle to the ball of the foot area and the metatarsal heads.

Advantageously, the elasticity of the elastic zone is such that the bent sole has a tendency to flex back and rebound into the neutral plane position. By flexing and rebounding in harmony with the ski the user is able to feel proprioceptively and to coordinate effectively with the ski's most favorable behaviors. Preferably, the elastic zone allows bending about a transverse axis in the metatarsals. This enables the foot to bend naturally while skiing as it does in walking and hiking boots. According to a preferred embodiment of the ski boot the elastic zone is designed such that in addition to bending about a transverse axis a precisely managed torsion of the rear sole portion with respect to the front sole portion about the longitudinal boot axis is possible. Substantial resistance to sole and shaft torsion is favored to the inside for the precise transferring of steering and edging forces from the lower leg shaft over the medial edges, while allowing liberal torsion over the outside edges to permit natural and dynamic alignment of the lower leg anatomy and control of balance at all times.

Advantageously, either the intermediate shell portion or the sole comprises a guide or deflection means for causing a torsion of the front and rear boot portions about the longitudinal boot axis when they are bent with respect to each other. By this means the forces exerted by the skier can be directed most effectively e.g. to the medial side of the ski in order to support edging when most needed in difficult snow and terrain. The guide means can be one or more transverse beams formed in the sole and/or one or more transverse cuts in the intermediate shell portion. The beams may extend at an angle to the longitudinal boot axis.

Preferably, the guide means are arranged such that the rear boot portion is deflected laterally relative to the front boot portion. This allows for a natural and dynamic alignment and adaption of the lower leg for maintaining balance and control. There may be flex cut adjustment or blocking means provided for insertion into the transverse cuts to limit or adjust the maximum relative flexing or reduction of the opening between the front and rear boot portions. This allows the ski boot to adapt naturally to the individual skills of the skier. The adjustment or blocking means can be plugs, bolts, retaining plates or the like. In order to prevent opening of the flex cuts in the intermediate shell portion, a connecting means can be provided for interconnecting shell portions located in front and behind the cuts or openings.

Advantageously, the intermediate shell portion extends from the front shell portion forming the toe cap to the shaft and preferably comprises an opening at least in the metatarsal area. An opening in the metatarsal area is a simple means for creating a boot whose front and rear shell portions are bendable relative to each other. Preferably, the opening in the outer boot shell extends from the instep towards the sole. The opening in the metatarsal area may be V-shaped, round or oval or can be designed as longitudinal cuts or slots. It is to be understood that the opening may extend even as far as to the shaft without compromising the advantages of the novel boot.

If cuts are provided in the shell, then they can extend from the instep in a curve forwards and downwards (curved cuts). Instead of providing an opening or cuts, the intermediate shell portion may be made of a flexible material which is foldable or compressible to allow as much as about 15 mm reduction over the metatarsals to allow the bending between the front and rear parts of the ski boot sole.

According to a preferred embodiment the elastic zone comprises an elastic, preferably removable insert. Alternatively, the sole may comprise in the longitudinal direction areas of different elasticity so that the desired bendability of the sole is achieved. Another embodiment provides that the elastic zone comprises a structurally engineered elastic inner shell reinforcement frame insert permanently embedded in the outer boot. The elastic frame insert may comprise an easily bendable corrugated section in the metatarsal area. Said corrugated section may be sandwiched between a flat upper layer and a flat lower layer which bond the corrugations to create the desired dynamic response and elasticity in bending and torsion. It is desirable that the range of bending motion downward is limited to a maximum 3 mm from the neutral plane of the sole and that at the same time the tendency for any bending motion upward is blocked. An adjustment system can be provided so that the bending motion of the sole can be regulated to about 3 mm according to the skier's weight and ability level.

Advantageously, the outer boot comprises an inner shell frame that allows downward bending in the metatarsals while blocking tendencies to bend upwards. If a inner shell frame is provided, then the outer boot shell plastics can be thinner and flexible as the desired technical features are incorporated into the inner shell frame. The inner shell frame may be spoon shaped in the metatarsal area so that downward flexing is possible but upward flexing blocked. According to another embodiment the inner shell frame comprises corrugations in the metatarsal area that allows downward flexing but block tendencies of the boot sole to flex upwards. According to a still another embodiment the sole comprises a rigid leaf type spring imbedded in the sole plastic to allow a designated range of bending and dynamic response downward. The advantage of a leaf type spring is that its dynamic properties can be easily designed and controlled. It can be incorporated in the sole at a favorable price.

Preferably, the insert is designed as a flex and torsion box, or two opposing leaf springs, positioned under the imbedded reinforcing frame that is open at both sides of the sole to allow a designated amount of downward bending elasticity and blocked from upward bending, with the respective dynamic rebound response of both the top and bottom surfaces. Advantageously, the flex and torsion box connects the top and bottom surfaces of the sole with a vertical reinforcing I-beam membrane positioned in the sagital plane so that bending pressures on the top surface are transferred directly to bend the bottom surface to create a more effective bending and torsion box zone. This vertical I-beam or other effective material and shape can be snap fitted into position when desired and avoids deformation of the torsion box when flexing, retaining the optimum strength and dynamic properties of the torsion box. Other torsion box adjustment inserts, such as blocks made of assorted material properties, can also be used.

Another embodiment of the sole provides that the reinforcement of the torsion box insert may be designed such that the superior surface closest to the metatarsal bones is thinner and flexible, while the distal surface is made completely rigid to resist all bending forces. In this embodiment just the front and rear shell portions pivot relative to each other but not entire sole itself. The properties of the insert may be premolded with assorted dynamic response qualities. Although the insert is preferably integrated into the sole of the shell it can also be molded into detachable toe and heel walling sole plates, that are attached to the shell's sole, e.g. by screws or snap-fitted over respective retainers molded into the shell's sole.

According to a preferred embodiment the outer boot comprises an inner shell frame extending in or on the sole and also upward to form a part of the heel and ankle shaft. This design has the advantage that medial and lateral flexibility, and torsional rotations of the lower leg can be managed intentionally by design. Advantageously, the inner shell frame comprises on the medial side a shaft that extends a designated height above the medial and lateral ankle bones, and wraps around the heel area as an interconnected and stabilizing heel counter. Thereby the desired control of both medial and lateral shaft torsion, and the respective internal and external control of the lower leg shaft torsion when edging and steering the skis can be achieved. Preferably, the sole, rear and front shell portions are made from one piece.

Advantageously, the sole comprises a detachable lower sole. The lower sole can incorporate the desired flex and torsion characteristics so that the qualities of the ski boot sole can easily be altered according to the skier's weight and ability. Although the lower sole can be made in one piece, the detachable lower sole is preferably made in at least two separate portions, namely a toe and a heel portion. Said portions may be attached and secured to shell's sole by screws, bolts, snap-on connections and the like.

Like conventional boots the ski boot according to the invention can comprise an outer boot shell, preferably made of an unyielding plastics, and a soft inner boot or lining. Preferably, the inner boot is removable or retractable from the outer boot.

In order to provide a good hold of the ankle in the ski boot, ankle fixing and attaching means are provided which extend from the medial (inner) side of the outer boot to the lateral (outer) side and embrace and pull the ankle and heel of the skier back into the heel portion of the shell and inner boot. Preferably, flexible and essentially non-stretchable strap means are used as fixing and attaching means. The closures may be any of the known closure means known in the art. Advantageously, the ankle fixing and attaching means are arranged at an angle greater than 120 degrees, preferably at an angle between 130 and 145 degrees with respect to the sole for pulling the ankle of the skier's foot back into the heel portion.

According to a preferred embodiment of the invention the first or top lower leg fixing and attaching means are flexible but essentially non-stretchable strap means attached to the spoiler of the shaft. Said first strap means can be a part of the outer boot shell plastics or separate textile or plastic straps. It is of importance that the first strap allows to couple the inner boot and leg shaft effectively and with minimal or no play to the outer boot shaft or spoiler. The top lower leg strap may extend inside the outer boot shaft for embracing the inner boot and lower leg shaft directly with no outer boot shell plastics between strap and inner boot shaft. Preferably, the top leg fixing and attaching means are attached or fixed to the shell shaft spoiler a short distance from the top of the shaft end for coupling the upper inner boot and lower leg shaft end with a minimal or no play between the shaft and spoiler, respectively. This ensures that a maximum momentum can be applied to the elastic zone through the rigid shaft and spoiler portion. There may be provided second and third lower leg fastening and attaching means in the shaft portion which can be part of the outer boot shell plastics. Advantageously, foot fastening means are provided in the metatarsal region of the outer boot. Advantageously, foot fastening means are provided in the metatarsal region of the outer boot for user friendly adjustability.

It is of importance that the instep portion of the outer boot above the ankle fixing and attaching means is compressible or yielding so that the ankle can effectively be embraced by the ankle strap means. Flexible and elastic strap means have the advantage of adapting more readily to variables in foot volumes, shapes and adaptive activity, while also allowing for natural motions without losing support or control.

Object of the present invention is also a ski boot characterized in that the sole of the outer boot is made of an essentially rigid material, preferably plastics, comprising an elastic zone in the metatarsal region of the sole dividing the sole into front and rear sole portions; and an intermediate upper shell portion is provided between the front and rear shell portions of the outer boot, which is designed such that front and rear shell portions are bendable or pivotable with respect to each other, and wherein the front sole portion and the shaft are interconnected by at least a cable extending from the boot shaft to the front sole portion. By this design the elastically bendable toe cap is coupled with the rigid shell spoiler shaft so that forward knee motions that activate the force triangle cause increased tension of the cable and immediately increase both the sole's resistance to bending and it's rebound rate, and proportionately to the amount of forward motion force applied by the skier. The same effect occurs when the bending and vibrational forces of the ski activate the sole and the cable tension respectively. Preferably, tensioning adjustment means are provided for the selected tensioning of the cable. Tensioning means can be a lever, knob or the like which cooperate with one end of the cable. Advantageously, the cable extends in grooves provided in the sole.

Yet another object of the present invention is a system comprising a ski boot, as described above, a ski, and a ski binding comprising front and rear binding parts for receiving and fastening the front and heel boot portions, i.e. toe cap and heel of the boot. Advantageously, an replaceable or adjustable elastic or spring-based suspension element is provided which is mounted under the boot sole between the front and rear binding parts. The elastic suspension element assists the front and rear binding sole supporting platforms in transferring and absorbing the bending and vibrational forces from the ski to the boot sole, as well as from the boot sole to the ski, and help to amplify the tactile messages between the sensitive proprioceptive nerve sensors in the soles of the feet so that the skier may respond proactively and quickly to the constantly changing relativity between the skier, the skis and the snow surfaces. An adjustment screw system enables the skier to tighten or loosen the elastic or spring based suspension element to control the dynamic response and rebound rate of the elastic sole. The elastic suspension element assists the front and rear binding sole supporting platforms spacers in absorbing and transferring the bending and vibrational forces from the ski to the boot sole, as well as from the boot sole to the ski. This helps to amplify the tactile messages between the ski and the sensitive proprioceptive nerve sensors in the soles of the feet, so that the skier may respond proactively and quickly to the constantly changing relativity between the skier, the skis and the snow surfaces.

According to another embodiment of the system a curved leaf-type spring suspension element is mounted on the ski ahead of or under the front binding parts and behind the rear binding parts, by passing through hollow binding elevators, such that the curved spring element can cooperate with the boot sole surface when attached in the bindings. This is advantageous as the force exerted by the skier on the leaf spring suspension element effectively transfers forces from the skier ahead of and behind the bindings, for added influence over the skis, as well as working with the dynamic response of the sole in attenuating the high frequency vibrations and resonances that are generated and cannot be absorbed by the skis, and especially shorter length skis.

In theFIGS. 1 to 14different embodiments of ski boots11according to the invention are shown. The characteristics of the novel boot are an essentially rigid rear boot portion and a front boot portion being bendable or elastic with respect to the rear boot portion. In particular, the ski boot11has a sole13comprising an elastic zone15, where the metatarsus of the foot received in the boot will be located, dividing the sole13into a rear sole portion17and a front sole portion19. The rear sole portion17is integral with a rear shell portion21comprising a heel portion23and shaft25extending upwards from the circumference of the rear sole portion17. The front sole portion19is integral with a front shell portion27extending upwards from the circumference of the front sole portion19. Between front and rear shell portions21,27an intermediate shell portion29is located which extends from the shaft25to the front shell portion27. The front shell portion27essentially corresponds to the toe cap of the boot. Rear and front shell portions21,27are bendable relative to each other due to the elastic design of the sole13in the metatarsals and the intermediate shell portion29of the ski boot which is foldable or compressible at least in the region located above the elastic zone15.

According to the first embodiment shown inFIGS. 1 and 2the intermediate shell portion of the ski boot11comprises an opening31in the shell plastics extending behind the front shell portion27or toe cap. The opening31has a pear-like shape. The edges33of the opening31extend approximately from the rim edges of the instep portion a distance downwards to the sole, then parallel to the sole and again upwards to the rim edges of the instep. Due to the deep opening31in the metatarsal area the shell plastics presents essentially no obstacle to the bending of the front boot portion when the skier is walking or is pressing the knees forward when skiing. The opening31is usually covered by a more elastic and impermeable cover35which prevents the intrusion of snow and water.

According to a second embodiment shown inFIGS. 3 and 4the opening31is more apparent than in the first embodiment. The opening31extends not only just above the elastic zone15but from the deepest point of the opening31at an angle towards the shaft25leaving the shell more open. This is of importance for more effectively supporting the foot in the ski boot and in eliminating the infringement of the instep by the overlapping shell plastics. The space created is replaced with soft and pliable plastic parts that serve to insulate against snow and water, and to eliminate the transfer of unwanted forces between the skis and the front of the lower leg, and also to create a most efficient force triangle effect.

According to a third embodiment shownFIGS. 5 to 9the opening31is reduced to transverse cuts91a,91b. The cuts91a,91bare formed in the side panels of the intermediate shell portion29, which can overlap as in conventional ski boots. The cuts91a,91bare rounded and extend from the edge of the side flaps131,133or panels in a curve towards the sole13. The side flaps are covered by elastic and impermeable covers35a,35b. The covers are fixed to the intermediate shell portion29by rivets36and the buckle base plates38. Adhesives can also be used. InFIG. 8the reduction of the cuts91a,91bis illustrated when the shaft is bent forward.

Common to all embodiments is that the shaft of the lower leg is coupled with the liner against the rear spoiler shaft25, rear side shell portions40,42and rear sole portion to form an essentially stiff ensemble so that a force triangle is created. The force triangle as schematically illustrated inFIG. 10allows the user to apply a maximum lever to the metatarsal sole portion where the elastic zone15is located. The rear side shell portions40,42may be designed as reinforcements of the outer boot shell as illustrated inFIGS. 54 and 55. They can be designed as reinforced shell plastic sections that extend from the upper shaft at an angle downwards to the mid-foot area behind the elastic zone.

Although the shaft25may be made of one piece, the shaft25can comprise a cuff37being connected to the rear shell portion21. Unlike conventional ski boots the cuff37of the novel ski boot is connected to the rear shell portion21such that rear shell portion21and cuff37are rigidly interconnected. Reference numeral50designates the spoiler extending above the shaft25and/or cuff37, respectively, at their rear side. By way of example, the cuff37can be fixed to the rear shell portion21by at least two rivets46on both sides of the boot. The more rivets46that are used to fasten the cuff37to the shell shaft25the more supportive and rigid the shaft25and cuff system37become. The rivets46can be selectively added or withdrawn on either side of the cuff and shaft to create the desired amount of resistance torsion to the medial and lateral sides respectively and according to the skier's preferences. The rear shell portion21, shaft25and the cuff37are designed such that they are in a rigid relationship to more effectively brace the ankle from forward flexing motion. By this means the skier is able to introduce a force directly into the elastic zone of the sole13via the boot shaft25. If the skier exerts a force on the shaft parallel to the boot axis by bending forward with the knee, then a vertically downward directed force component (arrow26) results in the bending of the metatarsal sole region. This effect is illustrated inFIG. 10. As the sole13can be elastically deformed, the ankle essentially does not flex and the center of gravity of the skier can therefore be easily maintained in its most favored and balanced position. According to the conventional ski technique using a rigid sole and flexible or pivotable cuff shaft the ankle of the skier articulates and moves forward and backward when the skier bends forward or backward. Although not apparent at first, the novel design of the ski boot11, which is contrary to the design of presently commercially available ski boots, the important flex element has been moved from the ankle and leg shaft to the ball of the foot. This allows for better control as the forces can be applied more directly into the skis, without the usual deformation of the shell plastics with bending which causes a loss of stability and control, respectively.

For an optimum control it is of importance that the lower leg and ankle of the skier are attached to the shaft25with a minimum play by pulling the leg shaft back and fastening it against the spoiler with the power strap, before the cuff is closed with the closure fastening system. Until now the cuff closures were closed first and before the power strap, which was then closed on the outside and in front of the cuff. For this reason it is preferable that the outer boot is easily deformable or compressible at the instep and metatarsal portion29. In order to achieve this the opening31of the rather hard outer shell plastics preferably extends to the shaft25so that an ankle fastening means, e.g. a strap39, extending from the inner side of the boot to the outer side can embrace and more effectively pull the ankle and heel of the skier back into the heel portion23. The ankle of the skier is thereby essentially immobilized—unlike in conventional boots where the adaptability of the shell plastics is noticeably limited and often not effective in pulling the ankle and heel back into the heel portion. As the sole of the ski boot11can bend, there is also no tendency of the skier's ankle and heel to move forward or backward.

A first lower leg or shaft fastening means, e.g. a strap41, extending around the upper cuff or shaft portion is adapted to secure the lower leg of the skier to the shaft25with a minimum play. As can best be seen fromFIGS. 1 to 6and13and14the first shaft strap41is attached to the spoiler50so that inner and outer boot shafts are coupled at their upper ends. This allows the skier to apply a maximum force to the metatarsals by means of the rigid shaft and cuff portions. Optionally, second and third shaft fastening means, e.g. plastic straps or buckle fasteners43and44, can be provided along the outer boot shaft. The second and third straps may be integral with the outer boot shell plastics. Using two or more shaft straps41,43,44is optional and allows the skier more leverage in closing the cuff37and shell shaft25to support around the lower leg and ankle, and permits a more uniform and comfortable distribution of closing pressures. A foot fastening means, e.g. a strap or buckle fastener45, in the metatarsal region serves for the fixation of the forefoot. It is understood that a strap in terms of the present invention can be any of already known closures used with ski boots.

According to a fourth embodiment shownFIGS. 13 and 14the opening31is increased to significantly reduce the amount of shell plastic surrounding the foot and metatarsal bones. In contrast to the embodiments discussed above the fourth embodiment has an outer boot shell made of one piece. The outer boot comprises an essentially open shell47in which the inner boot49is received. The opening31extends from the toe cap27to the upper shaft end51. The ankle strap39is arranged at about 40 to 50 degrees to the vertical such that the ankle of the skier can be effectively fixed in the heel portion23. The inner boot49exceeds the edges33of the opening31so that the straps41and39cooperate directly with the inner boot49.

The straps39,41,43,45can be fastened to the outer boot by means of ordinary buckles53(FIG. 5), ratchet buckles55(FIG. 1), Velcro fastening means57(FIG. 13) etc. or the like.

InFIG. 14a cavity59is shown in the metatarsal region of the sole13. In the cavity59plastics plates61with different elasticity coefficients may be inserted and fastened so that the flexing characteristics of the sole13can be varied depending on the weight and ability of the skier, the equipment used etc. The foot strap45is mounted in the forefoot region directly on the upper surface of the sole of the inner boot and crosses on the instep portion of the inner boot49to act as a supportive closure system. This is the preferred forefoot closure and adjustment system in the shell embodiment depicted inFIGS. 3,4, whereby the crossing of the velcro supporting straps normally needs only one adjustment and fine tuning to the foot for the best support.

FIGS. 15 to 18show different embodiments of the elastic sole13. As illustrated inFIG. 15a first embodiment of a sole13has a reinforcement body63embedded in the sole13. The reinforcement body63provides for the desired flex and torsion qualities of the sole in order to control downward and to block upward sole elasticity, dynamic response and torsion. Alternatively, the reinforcement body63can be built into a replaceable toe and heel walking plates97,99which allow for adjustment of the sole elasticity to combine the boot sole elasticity and rebound qualities.

FIG. 16shows a further embodiment of an inventive sole comprising a leaf spring65embedded in the sole under the forefoot region. The leaf spring65can also be imbedded permanently into the shell sole or into detachable toe and heel walking soles97,99(FIG. 18). Various leaf spring properties and combinations, such as opposing leaf springs, can be predetermined and exchanged according to the demands of the skier's weight and ability.

FIGS. 18aand18bshow a leaf spring reinforcement insert sole with replaceable toe and heel walking sole plates that can be attached either by bolts or a plastic snap-on system that fastens onto premolded shell retainers. The replacement sole parts can also incorporate select dynamic properties to match the skier's weight and ability, and can also incorporate various degrees of sole angles relative to the horizontal plane to adjust easily for the biomechanical peculiarities of each lower leg alignment anatomy.

FIGS. 17aand17bshow the leaf spring system in neutral and unloaded position (FIG. 12a) and again in the dynamic loaded position (FIG. 17b). In this embodiment the sole has a concave surface67so that the sole's dynamic bending does not extend below the horizontal plane of the sole (FIG. 17b).

InFIG. 18a detachable sole13ais shown. The detachable sole13ais secured to the boot sole13with a bolt69and a screw71, which are inserted into a hole73in the soles13,13a. An alternative attachment system is shown with the heel17which is attached and fastened by a snap-on system73where the rear heel portion slides onto it's premolded notch75aand the forward heel portion is levered and stretched forward over the forward premolded notch75bwith a leverage tool or screw driver.

In order to control the flex and torsion characteristics of the inventive ski boot, the outer boot shell may comprise an essentially rigid reinforced inner shell frame77(FIGS. 19 to 21). The inner shell frame77is made of reinforced injection molded plastics or composite plastics and preferably from one piece. Preferably the frame is engineered such that it can control downward flex and torsion, and block upward flex of the sole. On the inner side the shell frame77has an upward extending ankle spoiler79in order to provide an optimum hold for the ankle, and to control both bending and torsional resistance between the horizontal plane of the sole and the medial side vertical plane of the shell shaft. The inner shell frame wraps around behind the heel and along side the lateral ankle to form a strong and stable heel counter to support the integrity of the sole and medial shaft relationship. In the forefoot region the frame77has a concave shape81and vertical extending side walls83a,83bthat allows bending downward and blocks bending upward. The inner frame77is fixed to or embedded within the surrounding outer boot shell plastics. The frame77embedded into the boot shell plastics allows controlled dynamic response qualities in downward flex and torsion, and connects the sole directly to the heel counter and medial aspect of the shell to eliminate unwanted distortion during the steering and edging of the skis.

FIG. 21shows a further embodiment of the imbedded inner shell frame77where corrugations85are used to allow controlled forefoot bending in the desired axis, while eliminating any sole torsion tendencies.

In order to achieve the desired boot sole characteristics reinforcing beams can be provided within or on the outside of the shell sole (FIG. 22). In this case a transverse beam87runs the entire length between the toe and heel areas of the ISO 5380 boot sole norm, from the medial aspect of the toe plate97to the lateral aspect of the heel plate99to reinforce against the sole's tendency to twist and torque with steering and edging motions of the foot and the leg usually directed at the ski's inside edges.

Another embodiment of a boot sole uses 3 reinforcing beams87a,87b,87cand siping cuts89in the beams87to allow downward bending at specific points in the beams, while restricting upward bending when the siping cuts are squeezed together. The beam87aextends parallel to the longitudinal boot axis on the inner (medial) side of the boot sole13. The second beam87bextends from the outer side of the heel walking plate at an angle to attach to the center of the longitudinal boot axis to the toe walking plate97. The beam87cextends a distance from the toe walking plate97backwards under the midfoot region. The asymmetric beam arrangement controls the sole torsion of the rear boot portion relative to the front boot portion when twisting and edging motions are applied to the sole, and blocks twisting internally to allow more stability and control of the skis, and to allow more pressure to be applied onto the skis inside edges.

FIG. 24shows an embodiment of the ski boot comprising an inner shell frame as illustrated inFIG. 19and siping cuts in the sole beams87. The inner shell frame77extends around the heel counter and the shell shaft. The opening31above the elastic zone in the form of a transverse flex cut91or slit permits the upper shell to close as the sole13bends. The depth of the flex cut91also determines the sole's flexibility combined with the shell's plastic thicknesses, resistance to elongation and the imbedded inner frame when used. The closer the flex cut91comes to the sole13the more bending is possible. The dotted lines show the initial position of the boot and the solid lines show the range of flexing action of the boot in action, where the forward motion of the cuff37causes the bending of the sole13through a force triangle.

FIG. 25shows another means of adjusting the sole bending and dynamic response qualities: In this case rigid composite or metal rods93are inserted into premolded slots95within the imbedded reinforcement and shell plastics. The rods93block the tendency for the sole to flex downward and their predetermined physical properties also adjust the dynamic response qualities.

InFIGS. 26 to 28a cable assembly, protected within the reinforcing beams87of the sole13and covered with the toe and heel walling plates97,99, is looped around a molded mushroom101or stop under the toes and curves through guiding grooves103a,103bwithin the convex external aspect of the imbedded reinforcement. Two cables105a,105bare stabilized through tension guides107under the midfoot and the heel, and continue separately or are joined into one cable109to pull vertically through another cable tension bridge111at the back of the shell. These tension bridges107,111work like the string bridges on a violin. The cable ends loop around another molded mushroom113inside the top of the spoiler, or through a buckle or spool adjustment mechanism115on the back of the shell. Then, when the lower leg flexes and pulls the spoiler forwards, the cable109is pulled and tensioned tighter against the convex surface of the imbedded reinforcement under the forefoot and proportionately increases the stiffness and dynamic response of the sole while the spoiler also restrains the forward motion of the lower leg.

The tension bridge107can be engineered as a cam rod121with a triangular cross-section providing three tensioning positions (FIGS. 29 and 30). The cam rod121has two grooves123a,123barranged at a distance from each other. The grooves123a,123bare guides for the cables125a,125band have different depths so that depending on the flat side on which the cam rod rests selected tensions can be applied to the cable assembly. The rod121can be rotated into one of three positions to apply different tensions to the cables105a,105band109, respectively. The cables105a,105band109control the concave frame ability to bend and alters the spring rate and dynamic response. The tension of the cables105a,105band109can be released by an adjustable buckle or micro adjustment spool125(FIG. 32).

Increased cable tension against the convex surface of the imbedded reinforcement frame, adjusts and increases the resistance of the sole13to bend—as well as—how far the sole can displace downwards and the sole's dynamic response, rebound or spring rate. This enables the skier to adjust the sole13according to weight, ability and energy level and the dynamic response performance of the skis.

The tension adjustment bridge can be inserted into a channel117through the side of the sole. This allows the cable to be positioned on one of several grooves of various depths to progressively increase the cable tension and thereby control the dynamic response of the sole flex.

Drawing26also shows a preferred system for sealing out snow and water from the flex slot between the buckles on the four buckle boot model. The material used is impermeable to snow and water, affected little by changing temperatures, and it is soft and flexes easily.

There may be more than one flex cut91in the instep portion of the outer boot shell. The embodiment of a boot shown inFIGS. 28 and 29has two flex cuts91aand91barranged at a distance from each other in the instep of the outer boot shell. The flex cuts91aand91bextend at an angle with respect to the longitudinal boot axis127. The flex cuts are angled in the same direction so that when flexing begins they deflect the rear shell portion in the same direction. As the lower leg moves forwards the axis of the upper rear part of the outer shell is deflected laterally with respect to the front part of the shell. This causes the front part to effectively increase angulation and will torque the sole medially over the ski's inside edges. This can be a preferred performance quality for advanced and expert skiers to facilitate increasing edging pressure and ski control at high speeds and in complex snow and terrain situations when it is otherwise strenuous and difficult to edge and manage the skis.

As can be seen in more detail inFIG. 29the medial cut91aof the rear shell deflects under the front shell flap131, and the lateral cut91bof the rear shell deflects over the front shell flap133, causing the front part of the shell to deflect downward toward the inside medial edge of the sole and ski edges.

Determining the length or depths of the flex cut depends on the collective response of the shell plastic and inner frame reinforcements to the designer's desired sole flexing behavior. Generally, the longer or deeper the flex slot cut into the shell the softer and deeper the sole flex will become. Consequently, the sole flex can be adjusted by shortening the effective length of the flex slot. The shorter the length of the flex slot the “stiffer” the sole flex becomes.

Flex cut adjustment or blocking means, e.g. plugs, bolts or other inserts, can be provided for adjusting or limiting the maximum relative flexing of front and rear boot portions. According to a preferred embodiment the flex cut adjustment means comprises a longitudinal retaining plate137with a plurality of upwards extending plugs138with external retaining brims139arranged at a distance from each other (FIG. 37). The plugs138can receive a screw141, which, when inserted, blocks and limits the forward motion of the rear shell portion. The retaining plate137can be inserted and screwed into position as shown inFIGS. 35 to 38. The plugs138are seated into the flex cut91and cooperate with the adjacent edges of front and rear shell portions. It is understood that the retaining plate is preferably a premolded rubber like insert made e.g. from rubber or another elastomer unaffected by temperature changes. The stiffest position is attained with all three positions blocked. With one, two or all three positions relieved the flex slot becomes relieved and progressively softer. When the flex cut closes the empty rubber plugs138are compressed easily (FIG. 38b). By adding screws141in the two lower plugs, the plugs can no longer compress and thereby reduce the effective length of the flex cut91and stiffen the sole flex. The skier can adjust the medial and lateral bending resistance separately.

In order to prevent opening of the flex cuts91, e.g. when the skier is leaning backwards, the front and rear shell portions may be interconnected by non-stretchable connecting means143, e.g. a strap, reinforced webbing or the like. By this means the most desirable edging and rotational supportive qualities of a normal ski boot are preserved, while the flex slot can close and reduce as desired. The connecting means143in the form of a reinforced webbing is attached to the upper front and rear shell portion by rivets or bolts145.

When the medial aspect of the rear shell is connected to the toes of the lateral aspect of the shell by a transverse bridge143of reinforced webbing, the opening of the flex cut can be more effectively controlled (FIG. 40). Thereby the webbing strap is anchored in line with the shell deforming torsional forces that result from edging.

FIGS. 41 to 43show an embodiment of an outer boot shell comprising an integrated bridge147molded into the shell for blocking the flex cuts from opening when opening forces are applied. The transverse bridge147is designed soft and flexible enough so that it can bend easily without interfering with the sole's bending qualities (FIG. 43), but can effectively block any further opening of the flex cuts91when the skier leans backwards.

The embodiment illustrated inFIGS. 44 and 45are characterized by a reinforced webbing151which is attached with rivets152to the boot shell. The webbing151extends approximately parallel to the forward flex cut91aconnecting the toe cap with the rear shell portion. Creases153provided in the webbing151for favoring a folding of the webbing151when front and rear shell portions are bent relative to each other.

Common to all embodiments is that the webbing151or connecting means bridge the shell gap or flex cuts above the sole bending area. The webbing151may be riveted into position and even secured by buckle base plates155as shown inFIG. 46. The webbing bends easily to allow for the closing of the shell upper gap or cut91but blocks any tendency for the gap to open, either by backward pressure on the spoiler or driving against the shell's torsional resistance to steering and edging forces.

The embodiments ofFIGS. 47 to 53have a torsion box157built into the imbedded reinforcement frame with a bubble relief156on the superior (proximal) surface of the sole. This allows for a pre-stressed and dynamic bending surface to be created respective to the less bendable lower (distal) surface.

FIGS. 52 and 53show a cross section of the shell and the torsion box157with a flexible superior surface and a fully reinforced inflexible distal surface that cannot be flexed. This means that only the upper opening or slot system and the internal parts of the shell will bend and deform dynamically as needed while the external aspect of the shell sole will not bend or deform at all. This can be important in consideration of the mechanical relationship to some binding functions and the demands of skiers in extreme skiing situations where the forces are very high and the sole bending and rebound qualities must be controlled and finite.

The ski, ski binding and ski boot system shown inFIGS. 54 and 55comprises a leaf-spring type suspension element164mounted under the boot sole13on the ski surface. Reference numeral designates the ski. The suspension element164extends through binding spacers160under the rear and front bindings158,159. A mounting and adjustment plate165provided at the ends of the suspension element164facilitates the attachment thereof to the ski surface. The suspension element164may additionally be in contact with an elastic or spring-based suspension element161mounted under the elastic zone15. The elastic or spring-based suspension element161may comprise a tension adjustment element162. On the upper surface of the leaf-spring type suspension element164may have a mounting and adjustment plate which is in contact with the boot sole13when the boot is mounted in the binding.

FIG. 56shows an embodiment of an inner boot49for use with an inventive ski boot. The inner boot49or liner is constructed with select reinforcement materials169, that are laminated to the outside of the liner or under liner's outer skin materials, or in a combination of both, to create a gentle transition and lamination that complements the hard shell plastic and the supportive padding systems that serve to protect and insulate the foot and lower leg. The reinforcements169can be flexible and thermally moldable, designed and assembled asymmetrically according to the asymmetrical and biomechanical supportive needs of the foot and lower leg, so that they combine to create a combined lamination with the shell plastics to create a sandwich structure stiffening effect. This means that thinner and lighter outer shell plastics can be used, which are also more adaptable and flexible, so that they are more readily bent and layered in combination with the outer shell plastic and uniting to create an effective and adaptable lamination of stiffening and supportive materials. In addition the more flexible shell and liner materials also make the boot considerably more user friendly and comfortable, being also easier to put on the foot, to adjust the closures and then to take the boot off. The inner boot49has a tongue171with optional reinforcements173. A short distance from the top of the inner boot shaft175a strap177is provided. The strap177is preferably a Velcro-strap which can also be used as first lower leg fixing and attaching means when it is fastened to the rear spoiler shaft25of the outer boot. The end of the strap177is held by strap guides179.11ski boot13sole15elastic zone17rear sole portion19front sole portion21rear shell portion2123heel portion25shaft26arrow indicating resulting vertical force component27front shell portion29intermediate shell portion (or instep portion)31opening33edges33of the opening3134transverse axis in the metatarsal region35elastic (rubber) cover covering opening36rivets for fastening elastic rubber37cuff38buckle base plates39ankle fixing and attaching means (ankle strap)40,42medial and lateral rear side shell portions41first lower leg or shaft fastening and attaching means (first or top power strap)43second lower leg or shaft fastening and attaching means (2nd power strap)44third lower leg or shaft fastening and attaching means (3rdpower strap)45foot strap46rivets for fixing cuff47open shell of 4thembodiment49inner boot50spoiler of the outer boot shaft51shaft rim53buckle55ratchet buckle57Velcro fastening means59cavity61plastics plates63reinforcement body65leaf spring67concave surface69bolt71screw73snap-on system75a,75bnotch77inner shell frame79ankle spoiler81internal concave shape of the sole in the forefoot region83a,83bside walls85corrugations87beam89siping cut91flex cut (transverse slit in the outer boot shell above the elastic zone)93metal or composite rod95premolded slots97toe walking plates99heel walking plates101molded mushroom103a,103bguiding grooves105a,105bcables107tension guides109cable111cable tension bridge113another molded mushroom at the top of the spoiler115spool adjustment mechanism117channel for cam rod121cam rod123a,123bgrooves of the cam rod125buckle for tensioning the cables105a,105band109127longitudinal boot axis129arrow indicating lateral deflection of the rear boot portion131front shell flap133rear shell flap137retaining plate138from the retaining plate upwards extending plug139external retaining brim of retaining plate141screw for plug137143connecting means for connecting front and rear shell portions145rivets or bolts for connecting webbing to front and rear shell portions147integrated bridge moulded into the shell plastics151webbing152rivets for fastening webbing153creases155buckle base plate156bubble relief157torsion box system158rear binding159front binding160binding spacers161elastic or spring based suspension element162tension adjustment element for elastic or spring based suspension element163leaf-spring type suspension element164suspension element and boot sole pressure dispersion plate165leaf-spring mounting and adjustment plate169reinforcement materials and sections, respectively171tongue173reinforcements on tongue175inner boot shaft177strap179strap guides