CROSS REFERENCE TO RELATED DOCUMENTS

[0001] The present invention claims benefit of priority to U.S. Provisional Patent

Application No. 62/917,748 of Daniel POST, entitled "SKI BOOT WITH A CONTOURED SPRING FOR ELASTIC ARTICULATION," filed on 27 DECEMBER 2018, now pending, the entire disclosure of which is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

[0002] The present invention generally relates to ski boots, and more particularly to a rear entry articulated lever-type ski boot with a contoured spring along the front to provide enhanced comfort and performance, and conservation of energy for the skier.

DISCUSSION OF THE BACKGROUND

[0003] Over the years, various vintage and current rear entry ski boots have been designed to offer relative comfort and ease of entrance and exit. However, rear entry ski boots are reputed to be inferior to front entry ski boots for performance. The combined qualities of excellent comfort, ease of entrance and exit, and excellent performance are sought by the skiing public and the ski industry. In addition, easy and rapid fitting of boots to the skier, advantageously, would be beneficial at ski shops, rental shops, and for individual skiers.

SUMMARY OF THE INVENTION

[0004] Therefore, there is a need for a method and system that addresses the above and other problems. The above and other problems are addressed by the illustrative embodiments of the present invention, which teach the construction of rear entry ski boots with unique contoured spring arrangements that enable elastic articulation, while preserving an unencumbered form and attractive appearance of the ski boot. Illustrative implementations also feature enhanced leverage and amplified edging action from the prior art. The material for the contoured spring can be unidirectional carbon fiber composite, advantageously, employed for its exceptionally high strength, its high stiffness and its low weight. The present invention also specifies a unique rear closure for rear entry ski boots, such that ease of entry and exit is greatly enhanced. Additionally, the rear closure arrangement allows diverse designs of ski boot liners that would not otherwise be applicable. The present invention also specifies easy and rapid means of adjustment. The major benefits include enhanced skier performance, significantly reduced skier effort and fatigue, comfort, and ease of entry/exit, all achieved with an unencumbered and attractive shape of the ski boot. [0005] Accordingly, in illustrative aspects of the present invention there is provided a rear entry ski boot for a ski, providing elastic articulation, including a shoe to hold a foot of a skier; an articulated lever extending upwards to an upper portion of a lower leg of the skier, connected to the shoe; a stiff yoke attached to an upper portion of the articulated lever; and a flexible strap attached to the yoke to engage a calf of the skier and encircle the leg of the skier, and having a contoured spring of high stiffness, positioned substantially along the front of the ski boot. The contoured spring engages the ski boot at an upper location on the lever and at a location in a front portion of the shoe, and is substantially free of contact and friction along its length.

[0006] The ski boot further includes an articulated rear closure attached to the shoe.

[0007] The yoke is an integral part of the lever.

[0008] The ski boot further includes a shallow yoke pad attached to the yoke to engage a front of the leg of the skier.

[0009] The contoured spring has a hinged end at both the front portion of the shoe, and at the upper location on the lever.

[0010] The contoured spring has a fixed end at both the front portion of the shoe, and at the upper location on the lever.

[0011] The contoured spring has a fixed end at the front portion of the shoe, and a hinged end at the upper location on the lever.

[0012] The contoured spring has a fixed end at the front portion of the shoe, and a free end at the upper location on the lever.

[0013] A cross-section of the contoured spring is substantially uniform along its entire length.

[0014] A cross-section of the contoured spring is not uniform along its length.

[0015] The contoured spring is protected by a cover.

[0016] The contoured spring is positioned substantially along the front of the ski boot and lies inside the ski boot.

[0017] The contoured spring is positioned substantially along the front of the ski boot and lies outside the ski boot.

[0018] The contoured spring is made of multiple elements, positioned substantially along the front of the ski boot.

[0019] The ski boot further includes an instep strap to hold a heel of the skier in a heel pocket of the ski boot. [0020] Tension on the instep strap is adjusted by instep pads of various thicknesses.

[0021] An adjustable strap engages a rear closure of the ski boot and the lever to fasten the rear closure in a closed position.

[0022] The ski boot further includes a rotate-and-lock device that adjusts tension on an instep strap of the shoe to maintain a heel of the skier in the heel pocket of the shoe.

[0023] In a further illustrative aspects of the present invention there is provided a rear entry ski boot for association with a ski, including a shoe portion of a ski boot having a rear portion that is open at and above a level of a footbed of the shoe; and an openable rear closure having padding that forms a portion of a heel pocket of the shoe and that lies at and above the footbed and is hinged to the shoe.

[0024] The openable rear closure is fastened and locked to the shoe by an adjustable strap.

[0025] The openable rear closure is fastened and locked to the shoe by a latch.

[0026] The ski boot further includes a rotate-and-lock device that adjusts tension on an instep strap of the shoe to maintain a heel of the skier in the heel pocket formed by the rear closure and a rear portion of the footbed.

[0027] Still other aspects, features, and advantages of the present invention are readily apparent from the following detailed description, by illustrating a number of illustrative embodiments and implementations, including the best modes contemplated for carrying out the present invention. The present invention is also capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

[0029] FIG. 1 shows an illustrative schematic exterior view of an illustrative implementation in which the contoured spring for elastic articulation is installed in the interior of the ski boot;

[0030] FIG. 2 shows an illustrative cross-sectional view through the flexible strap near the top of the ski boot; [0031] FIG. 3 shows an illustrative partial cross-sectional view along the front of the ski boot representing a contoured spring with hinged end conditions, where the contoured spring is located in the interior of the boot;

[0032] FIG. 4 shows an illustrative partial cross-sectional view along a horizontal plane that passes through an upper part of the boot, illustrating the contoured spring located under a ridge that extends along the length of the spring;

[0033] FIG. 5 shows an illustrative view of the force vectors that act on the contoured spring;

[0034] FIG. 6 shows an illustrative view indicating the forces exerted on the lever by the skier and by the contoured spring;

[0035] FIG. 7 shows an illustrative view of all the forces acting on the lever;

[0036] FIG. 8 shows an illustrative view of the forces exerted on the shoe by the contoured spring and the lever;

[0037] FIG. 9 shows a graph of the suggested force vs. displacement parameter at a point near the top of the lever;

[0038] FIG. 10 shows an illustrative partial cross-sectional view of the contoured spring designed for a preload;

[0039] FIG. 11 shows an illustrative view indicating the deformation of the contoured spring;

[0040] FIG. 12 shows an illustrative view of the contoured spring under fixed/hinged end conditions;

[0041] FIG. 13 shows an illustrative view of the contoured spring under fixed/fixed end conditions;

[0042] FIG. 14 shows an illustrative view of the contoured spring under fixed/free end conditions;

[0043] FIG. 15 shows an illustrative partial cross-sectional view along the front of the ski boot for an illustrative implementation, where the contoured spring, under hinged/hinged end conditions, is installed on the exterior of the ski boot;

[0044] FIG. 16 shows an illustrative partial cross-sectional view of a channel that protects the exterior contoured spring;

[0045] FIG. 17 shows an illustration of diverse cross-sections for a contoured spring including multiple elements; [0046] FIG. 18 shows an illustrative, schematic, composite, exterior view of a rear entry ski boot in which the portion of the heel pocket above the footbed is built into the rear closure;

[0047] FIG. 19 shows an illustrative, schematic, exterior view of another rear entry ski boot in which the portion of the heel pocket above the footbed is built into the rear closure;

[0048] FIG. 20 shows an illustrative, schematic diagram of a rotate-and-lock device, located in the hollow rear sole of the ski boot, employed for adjustment of the instep strap; and [0049] FIG. 21 shows an illustrative, schematic diagram of another rotate-and-lock device, located in the hollow rear sole of the ski boot, employed for adjustment of the instep strap.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] A rear entry ski boot designed for alpine skiing was introduced by one company in

1980. It became extremely popular, known for its good comfort and reasonably good skiing performance. That same year, another company introduced a front-entry ski boot that became the boot of choice for downhill racers. Advertisements and views expressed by ski experts and pundits favored the higher performance front-entry boots. The high-performance argument prevailed and succeeded in the market, and that fashion persists. In the last three decades, front entry racer style ski boots have dominated, pushing rear entry ski boots to near extinction.

[0051] In 2017, SIA (Snowsports Industries America) reported two issues concerning skier participation: (1) too many new skiers drop out after their first day, and (2) experienced older skiers drop out prematurely. The present invention includes recognition that both problems of retention relate largely to ski boots. For example, for many beginners, the racer style ski boots are uncomfortable and unforgiving. Older experienced skiers want high performance boots, but with their loss of flexibility and strength, they find it torturous to put the racer style boots on and to take them off.

[0052] Current pundits and opinion leaders recognize that recreational skiers of diverse abilities are seeking greater comfort, i.e., the comfort offered by rear entry boots. They recognize, too, that the recreational skiers want enhanced performance together with comfort, and attractive physical design.

[0053] Since the mid-1980s ski boot manufacturers concentrated on front entry boots with articulated (hinged) upper cuffs, facilitating forward movement of the knee and lower leg. However, the present invention includes recognition that elastic articulation, wherein energy expended in this forward movement is recovered as the skier returns to the neutral position, has been woefully neglected. For example, without elastic articulation, energy is lost to friction and hysteresis.

[0054] Whereas all vintage and current rear entry ski boots offer relative ease of entrance and exit, the present invention includes recognition that further improvement of ease would be a valuable asset, especially for older skiers. In addition, easy and rapid fitting of boots to the skier would be beneficial at ski shops, rental shops, and for individual skiers.

[0055] Referring now to the drawings, like reference numerals designate identical or corresponding parts throughout the several views, and wherein elements of an illustrative implementation are shown schematically in FIGs. 1 through 4. These elements are a shoe 1 suitable for mounting on a ski; a lever 2, having high forward, lateral, and torsional stiffness comparable to that of a rigid body, attached to the shoe by pivot 3 providing a hinged joint, and rising along the front of the leg to a level above the calf of the leg essentially at the knee joint; a flexible strap 4 to engage the calf of the lower leg; a rear closure 5 attached to the shoe by pivot 6 and secured to the lever by strap 7; and instep strap 8, which retains the heel of the foot firmly in the heel pocket inside the shoe. Projection 9 is a stop that limits the forward articulation of the lever; rearward motion is limited by stop 10, which is a protruding ridge along each side of the shoe that abuts the lever when in its neutral position. A ridge 11, of varying height, extends along the front of the lever and continues along the shoe.

[0056] A lining in the form of an inner boot, or equivalent padding, not shown in FIG. 1, fits inside the lower shell (parts 1 and 5). This insulating lining can be made firm and snug along the sides of the forefoot, but otherwise can be made soft and comfortable. The soft lining, in cooperation with the rear closure 5, can be made loose enough that it does not restrain rotation of the lower leg, the rotation that induces amplification of edging action.

[0057] Instep strap 8 can lie between the shell of the shoe and the lining, or it can lie between the lining and the foot of the skier. With the rear closure 5 secured to the lever by strap 7, cable 12 together with instep strap 8 presses the heel of the foot into the heel pocket of the shoe. For accurate fit, turnbuckles or other known means can operate in series with cable 12 to adjust the tension on the instep strap 8. In addition, or as an alternative, pads of suitable thickness and stiffness can be inserted to adjust the tension on the instep strap. For designs in which the instep strap lies between the shell and lining, the pads would be adhered or otherwise attached to the lining in the region of the instep. For designs in which the instep strap lies between the lining and the foot, the pads would be attached to the instep strap itself, to lie between the strap and the foot. In either case, pads of various thicknesses can be used for an accurate fit; multiple thin pads can be provided to be combined as a laminate to achieve the accurate fit, that is, to achieve the optimum tension on the instep stra p. Thus, the heel and forefoot are firmly positioned in the shoe for accurate steering of the ski. When the rear closure is opened, cable guide 13 is lowered, which relieves the tension on the cable a nd instep strap, thus allowing easy entry and exit of the foot. Internal guides in the shoe, not shown, align the cable for smooth action.

[0058] FIG. 2 is a schematic cross-sectional view through calf strap 4. Here, the hatched arc represents a yoke, which can be an upper portion of lever 2, as shown, or a separate stiff yoke, with stiffness similar to that of the lever, attached to the lever; flexible strap 4 is attached to the yoke, attached, for example, by Velcro (hook and loop) tape; the strap extends to encircle a skier's leg and extends further over the front of the yoke where it is fastened by means of a large area of Velcro tape. A shallow yoke pad 21, shallow to engage only 20% to 30% of the circumference of the leg at the level of the calf, is attached by double sided adhesive tape, or other means, to the inside surface of the yoke, to cushion the front of the leg and transfer the motion of the front of the leg to the ski boot. The pad 21 can be contoured to match the shape of the contacting part of the leg. The rear portion 22 of flexible strap 4 can be lightly padded, although experience has shown that no padding need be employed to support the skier comfortably and effectively in sit-back maneuvers. The calf strap 4 and the shallow yoke pad 21 can be raised or lowered along the height of the lever to fit the anatomy of the skier. Note that pad 21 is the only element that engages the lower leg along the height of the lever. This assures that the force applied to the lever by the lower leg is concentrated at the height of pad 21.

[0059] FIG. 3, which is a partial cross-sectional view along the front of the ski boot, illustrates the contoured spring 31, located inside the ski boot for this illustrative implementation. The material for the contoured spring can be a unidirectional carbon fiber composite. The spring is abutted at the bottom by a socket 32 in shoe 1 and abutted at the top by a similar socket 33 in lever 2. The distance between the top end and bottom end of the contoured spring becomes shorter when the lever is pressed forward during skiing. Note that the shortening is a consequence of the geometry of the ski boot. Thus, the spring is compressed by forces exerted at sockets 32 and 33. Significant contact of the contoured spring with the shoe and lever occurs only at these sockets. The end condition described here is called a hinged joint. No bending moment ca n exist at a hinged joint; the bending moment is zero at the top end and the bottom end of contoured spring 31. [0060] Sockets 32 and 33 have a semicircular shape in the contact area in order to reduce the stress concentration and the ends of the spring have a corresponding semicircular shape. As an alternative, the spring can be made with square ends and filler members 34 can be provided to engage the semicircular root of each socket.

[0061] FIG. 4 illustrates ridge 11 that extends along the boot and covers the contoured spring 31. In region 35, FIG. 3, where the lever shell overlaps the shoe shell, the ridge in the lever is enlarged to accommodate the overlap. This represents an illustrative implementation, but viable alternate designs can eliminate the ridge.

INTERNAL FORCES

[0062] FIG. 5 illustrates the contoured spring 31, where its end points are denoted by a and b. As the skier presses on the lever and advances it forward, distance ab is decreased; thus, the contoured spring is compressed by forces Q, as indicated by vectors. These forces lie along line ab, since a hinged joint cannot sustain a moment, and since the summation of moments (force times distance) about any point is zero.

[0063] FIG. 6 illustrates lever 2, now pressed forward as the skier exerts force F on pad

21, where the line of action passes through point c. The spring exerts force Q on the lever at point a. Force Q is divided into its vector components Q' and Q", which are parallel and perpendicular respectively to the line of action of F. Hinge 3 is denoted as point d. The angle between lines ab and ad is denoted by Q.

[0064] FIG. 7 illustrates the forces acting on the lever, where:

Q' = Q sin Q

Q"= Q cos Q

[0065] For equilibrium, the summation of moments about d equals zero, providing

Q' = F (cd/ad)

where cd is the distance between points c and d, and similarly for distance ad. Thus, the compressive force on the spring increases with F as:

Q = (cd/ad) (1/sin Q) F

[0066] Then the balance of forces parallel to F gives:

F' = Q' - F

[0067] At hinge point d, the forces that act on each side of the lever are Q"/2 and F’/2.

[0068] FIG. 8 illustrates the reactive forces that act on one side of shoe 1, again with half the total acting on each side of the shoe at point d. Additional forces acting on the shoe include the tension in cable 12, the weight of the skier, and forces exerted at contact points with the ski bindings and the ski.

PRELOAD, DESIGN CONSIDERATIONS

[0069] FIG. 9 is a suggested F vs. D profile for typical recreational skiers. D is the forward distance traveled by the lever at the height of point c (FIG. 7); F is the resultant of the distributed force exerted by the skier on pad 21, FIG. 2. The graph indicates a preload force at D = 0 to establish a fixed neutral position for the skier. Thus, the lever does not advance until the force reaches a threshold value. To achieve the preload, the contoured spring is designed as indicated by the dashed lines in FIG. 10. When installed in socket 33, it pushes back on the lever, but the lever is restrained by stop 10; the lever cannot move forward until F exceeds the preload force, FPRE.

[0070] The maximum forward motion is DMAC, which occurs when the lever abuts stop 9,

FIG. 1. FSTOP occurs when the lever first abuts stop 9; subsequent additional force exerted by the skier does not increase the forward motion of the lever and does not increase forces acting on contoured spring 31. For recreational skiers, suggested design parameters are FPRE = 9 pounds (4.1 kg), FSTOP = 45 pounds (20 kg), and DMAC = 1.5 inches (38 mm).

[0071] Materials suitable for the contoured spring 31 include unidirectional carbon fiber composite, titanium, and steel. The maximum stress in the contoured spring is determined by the maximum bending moment, Q (mn), where the moment arm mn (indicated in FIG. 5) is measured when D = 1.5 inches (38 mm).

[0072] Tables I and II provide numerical values for geometric, force, and stress parameters for the contoured spring of FIG. 3, the design profile of FIG. 9, hinged end conditions, and uniform rectangular cross-section for the contoured spring.

[0073] TABLE I

[0074] TABLE II

[0075] The forces reported in Table I are readily accommodated by the structure of the shoe and lever. Table II supports uniaxial carbon fiber composite as an excellent choice of material for the contoured spring.

[0076] When the lever is pressed forward, the contoured spring 31 changes shape; the spring moves away from the shell of the shoe and away from the shell of the lever. Thus, there is no contact, so no contact forces and no frictional forces occur along the length of the spring. FIG. 11 shows trace 111 of the contoured spring in its neutral forward lean position; superimposed is trace 112 for D = 1.5 inches (38mm). The maximum deviation is 0.23 inches (5.8 mm), which occurs near the instep of the foot. The ridge 11 shown in FIG. 1 can be designed to accommodate the deflection of the contoured spring.

[0077] Note that the contoured spring will have a slightly different shape when designed for a preload. Note, too, that the manufacturing tolerance on height, ab, of the contoured spring (and also on the distance between sockets 32 and 33) is not severe; a 0.04 inch (1.0 mm) change of length of line ab (FIG. 5) introduces a change of resistance of only 0.94 pounds (0.43 kg)·

POTENTIAL EN ERGY

[0078] When the leg of the skier presses forward with a force F (FIG. 6), the lever moves forward, at the level of point c, by a distance D. Energy is the integral of force multiplied by distance. Thus, as the boot is flexed, the energy absorbed by the boot is the integral of F times D. If the ski boot is designed for the force vs. displacement profile of FIG. 9, this integral is given by the hatched area under the curve, 40.5 inch-pounds (4.6 Joules) in this case. This is the energy expended by the skier to fully flex the ski boot.

[0079] This energy resides in the contoured spring. Force Q (FIG. 5) acts on the spring as a consequence of applied force F. As the lever articulates, the geometry of the boot assembly requires distance ab (Fig, 5) to decrease by distance d. This energy residing in the contoured spring is the integral of Q times d, which equals 40.5 inch-pounds. Technically, this is called potential energy. The potential energy residing in the contoured spring is equal to the energy expended by the skier to flex the boot.

[0080] Rebound occurs as the skier returns to the neutral position (D = 0), i.e., as the lever pushes back on the leg. Thus, the potential energy is withdrawn from the contoured spring and the energy is returned to the skier. This is conservation of energy. It is a unique benefit of elastic articulation. It prevails in every cycle of flex and rebound. Relative to skiing in conventional boots, the benefit for the skier is reduced muscular exertion and reduced fatigue.

EN D CONDITIONS FOR THE CONTOURED SPRING

[0081] FIG. 12 illustrates the contoured spring 31 with a fixed end near the toe of the shoe and a hinged end near the top of the lever. At the fixed end 121, the socket is much deeper, the surrounding material is relatively thick and robust, and one or more fasteners 122 are used to contain the spring. The three-dimensional shape at the front of the shoe adds stiffness to the socket, providing a high degree of fixation of the slope at the end of the spring. At the hinged end, the slope is not fixed. For this fixed/hinged combination, experiments with nearly ideal fixation indicate approximately 25% greater stiffness of the contoured spring, compared to the fully hinged spring. Thus, the same F vs. D profile can be achieved with a thinner or narrower spring. In addition, the deflection of the spring will be smaller in the section above the foot of the skier.

[0082] FIG. 13 represents a fixed/fixed end condition. Ideally, the slope of the spring is completely fixed in its sockets at both ends. Experiments with nearly ideal fixation indicated approximately 50% greater stiffness than the fully hinged spring. Again, the spring can be made thinner or narrower.

[0083] FIG. 14 represents fixation at the shoe and a free end condition at the lever. Part

141 is a low friction guide attached firmly to lever 2. When the lever is pressed forward, the top end of the contoured spring slides upward and the gap 142 between the spring and the boot closes. This deformation of the contoured spring is opposite that for hinged and fixed end springs, which move away from the boot shell. Stiffness of the fixed/free combination is relatively low; it is approximately 30% of the hinged/hinged arrangement. Consequently, the thickness required for the contoured spring is substantially greater.

[0084] The fixed/hinged, fixed/fixed and fixed/free end conditions of FIGs. 12, 13 and 14 are viable options, and further illustrative implementations.

EXTERIOR CONTOURED SPRING

[0085] Whereas an illustrative implementation incorporates the contoured spring in the interior, an additional implementation incorporates the contoured spring on the exterior of the ski boot. In that case the contoured spring is attached to the outside of the front of the boot. FIG. 15 is a partial cross-sectional view for this illustrative implementation, in which 151 illustrates the top of shoe 1 and 152 illustrates the front of lever 2, both engaged with contour spring 31 under hinged end conditions.

[0086] FIG. 16 is a partial cross-sectional view illustrating a channel 161 that runs along the top of the shoe and along the front of the lever; the channel protects the external contoured spring 31. The depth of the channel can vary. A cap 162 can fit over the channel and the contoured spring for additional protection. This illustrative implementation also provides elastic articulation with unencumbered and attractive appearance.

[0087] Again, the fixed/hinged, fixed/fixed and fixed/free end conditions of FIGs. 12, 13 and 14 are viable options, and further illustrative implementations.

CONTOURED SPRING DESIGNS

[0088] Contoured springs of uniform rectangular cross-sections have been described.

Additional options include contoured spring designs with cavities, slots, holes, tapered width, tapered thickness, other variations of width or thickness, and combinations of such features. Another family of options is represented by cross-sectional views in FIG. 17; the contoured spring can include two or more elements. In style 171, rectangular elements abut each other; the elements have a circular cross-section in style 172; the elements are separated in style 173; the elements are positioned in an arc in style 174. The elements can be bound by wire, tape, or other means, or they can be unbound. In practice, the number of elements can be varied to suit individual skiers.

OPEN SHOE ARRANGEMENTS

[0089] Vintage and current rear entry ski boots are constructed with the heel pocket incorporated in the shoe of the boot. In contrast, Fig 18 illustrates a construction in which the upper part of the heel pocket is built into the rear closure. The rear closure 181 is depicted, in superposition, in both its closed position and its fully open position.

[0090] In FIG. 18, shoe 182 has an open back; for this open arrangement, line 183 represents the back edge of the upper part of the shoe. Line 184 represents the footbed of the shoe, typically sloped at 4° relative to the bottom of the sole. The leg and foot of the skier is illustrated by 185. Hinge 186 connects the rear closure to the shoe. A comfortable insulating liner or equivalent padding (not shown) fits between the foot and the shell of the shoe; a separate portion of the liner can be adhered to the rear closure. To enter the boot, the foot slides directly into the shoe. Then the rear closure is raised to press the foot forward into the liner and against instep strap 187. The rear closure is fastened in its closed position by strap 188. Once the instep strap is adjusted for optimum fit by rotating shaft 189, the adjustment is semi-permanent; occasional adjustment can be performed.

[0091] With this arrangement, the heel of the skier is retained snuggly in the heel pocket of the boot, consistently, and very easily. To exit the boot, calf strap 190 and closure strap 188 are opened, the rear closure is lowered, and the foot slides out directly, encountering no obstacles. Thus, by building the upper part of the heel pocket into the rear closure, entrance and exit become extremely easy.

[0092] As a further benefit of open arrangements, new innovative designs of the boot liner become available. Part of the liner can be built into the rear closure, with the remainder located in the shoe. Note that the open arrangement is applicable for other rear entry ski boot designs, in addition to the lever-type boots illustrated here.

[0093] Another embodiment of an open shoe arrangement is illustrated schematically in

FIG. 19. Here, rear closure 191 is hinged and latched to shoe 192. Dashed line 193 represents the edge of the upper part of the shoe; the rear opening in the shoe continues along the bold line at the boundary of rear closurel91. The insert in FIG. 19 represents the top view of the rear closure, illustrated schematically, where hinge 194 joins the rear closure to the shoe and latch pin 195 locks the rear closure to the shoe. When closed and locked, the rear closure, together with its lining (not shown), form the upper part of the heel pocket. For entry and exit, latch pin 195 is raised to unlock the rear closure, the closure is hinged open, and the foot of the skier can slide directly in or out of the boot without encountering any obstacle. Note that various known latching means can be employed.

[0094] Normally, a snow shield would be added, as illustrated by dashed lines in FIG. 19; shown here in its open position, the shield consists of two sheets, 196, of fabric or flexible plastic, attached to each of the two sides of lever 197. I nsulating materials can be attached to shield 196. In use, the two parts are wrapped loosely around the leg, overlapping each other, and held together by mating elements 198 of hook and loop (Velcro) tape. Again, various designs of snow shields can be employed.

[0095] Seals for waterproofing can be provided for open shoe arrangements.

Alternatively, abutting lining materials can serve to block ingress of snow and water.

INSTEP STRAP ADJUSTMENT

[0096] Whereas the instep strap of FIG. 1 is actuated by the rear closure, FIGs. 20 and 21 illustrate versatile options. Referring to FIG. 18, instep strap 187 is tightened (or loosened) by rotation of shaft 189. Shaft 189 is the output element of a rotate-and-lock mechanism. It is located in the hollow rear portion of the sole of the shoe, represented by 201. Rotation of shaft 189 adjusts the instep strap for each skier by actuating cables 202, i.e., the cables that connect 187 and 189.

[0097] The rotate-and-lock mechanism in FIG. 20 is worm and worm wheel assembly 203, which is fixed to the sole; it is actuated by rotating the worm with a n external tool inserted into socket 204. The external tool can be a screwdriver type hand tool. For a ski shop or rental shop, the tool can be a socket head driver bit gripped in a portable electric drill or electric screwdriver, to facilitate quick adjustments. As a variation of this arrangement, a remotely controlled miniature electric motor can be attached permanently to the input shaft of part 203 to operate the mechanism. Note that the worm automatically locks the worm wheel against unintended rotation.

[0098] The rotate-and-lock mechanism in FIG. 21 utilizes slotted flange 211, which is an integral part of shaft 189. For adjustment, setscrew 212 is withdrawn using a socket head bit in an electric drill or electric screwdriver, the shaft is rotated by a socket head wrench or socket head screwdriver inserted in socket 213, and then the shaft is locked by reinserting the setscrew. The electric tools facilitate quick adjustments. FIGs. 20 and 21 illustrate rotate-and- lock mechanisms for adjusting the instep stra p in a ski boot, while other rotate-and-lock mechanisms are also via ble.

[0099] Advantageously, the invention provides a unique contoured spring, loaded exclusively at its ends, with a rear entry lever-type ski boot, in which the contoured spring lies along the front of the tall boot, either inside or outside its shell structure, enabling an unencum bered shape and attractive appearance. The kinetic energy stored in the spring is returned to the skier in each cycle of flex and rebound. The invention also provides a unique feature for entry into the ski boot, wherein an open shoe arrangement enables ease of entry and exit.

[00100] While the present inventions have been described in connection with a number of illustrative embodiments, and implementations, the present inventions are not so limited, but rather cover various modifications, and equivalent arrangements, which fall within the purview of the appended claims.