Abstract: The present invention provides a kind of skate, including a boot and a skating device connected to the boot, wherein the skating device is arranged along the width direction of the boot. The skate further includes a skating device mount for mounting the skating device to the boot, wherein the skating device can rotate 360 degree under the boot. The transverse skating device under the boot enables the sideward sliding direction, which bring more fun to the skaters. When the skating device is rotated to an angle and locked, the skate can slide inclinedly, which bring more challenges to the skaters. The skating device can rotate 360 degree freely or rotate different angle from two boots under the boot, which can cancel the shift of the knock-knee. The skating device can also be adjusted to be in line on the longitudinal direction as a traditional roller skate or ice skate.

Abstract: An article of footwear comprising a pliable upper component and a molded unitary support structure formed of a plurality of wall stuctures and methods of manufacturing are disclosed. Some embodiments include a sole and first and second side wall structures extending therefrom and partitioned from one another. The sole and the first and second side wall structures may be in part or entirely constructed of multiple layers of fibers having different orientations from one another and disposed in a hardened resin matrix. The pliable upper component comprises outer and inner panels that overlap the inner and outer surfaces of one or more of the side wall structures and are conjoined thereto.

Abstract: A replaceable blade system for ice skates is provided with a rotary retention latch located within an enclosed chamber of the holder of the skate. The rotary retention latch is configured with a release lever that is adapted to be accessed through an aesthetic aperture in the holder.

Abstract: An ice skate strip-blade holder that provides a means to remove, replace, tension, and maintain tension in a strip-blade fastened and tensioned on the holder. In a preferred embodiment, the strip-blade holder assembly includes a front segment fixed to the skate plastic superstructure; a latched, pivoting rear segment arranged to apply and maintain tension in the strip-blade. In a preferred embodiment, the pivot and latch are positioned such that the pivot carries the majority of the tensile load maintained in the strip-blade and the latch carries a minor component of this tensile load. This arrangement provides for easy latch release. The latch provides release of the rear segment for subsequent pivoting and unhooking of the strip-blade for replacement.

Abstract: The present disclosure is directed to an ice skate including a boot, a separately formed casing, a blade, and a fastener. The boot includes a boot chamber for receiving a skater's foot. The casing includes an upper portion, a sole plate, and a blade holder. The upper portion defines a casing chamber for receiving the boot. In one example, the casing is plastic. The sole plate includes abutting toe, arch and heel areas and has a cantilevered connection to the blade holder. In this cantilevered connection, the toe and arch areas of the sole plate are supported by the blade holder and the heel area is unsupported by the blade holder. The blade holder defines a slot for selectively receiving the blade. The fastener removably secures the blade to the blade holder. In one example, the blade further includes a toe pick for use in figure skating.

Abstract: An ice skate assembly for attachment to a boot has a skate blade and a blade heating arrangement mounted within a blade support. The blade is heated by resistive heating wire attached along a groove on each side of the blade. The blade is mounted in the support by an over-molded plastic strip which engages into a slot in the support as a wedged fit. A control circuit board is encapsulated on the top edge of the blade and connects to a battery pack is carried in the rear tower of the support. The blade is attached to the support by a screw for pulling the blade longitudinally of the blade and to draw an inclined wedge member formed by the over-molding into its receptacle.

Abstract: An ice skate assembly for attachment to a boot has a skate blade and a blade heating arrangement mounted within a blade support. The blade is heated by a row of field-effect transistors carried on a circuit board or another type of heating element encapsulated on the top edge of the blade in an over-molded plastic strip which engages into a slot in the support as a wedged fit. The blade is attached by an inclined wedge member a screw for pulling the blade longitudinally of the blade and to draw the inclined wedge member into its receptacle. The battery pack is carried in the rear tower which is sealed against moisture penetration and includes two proximity switches for actuation.

Abstract: A composite ice blade may have a metal ice edge bonded to a metal foil. The metal foil may be bonded to a plastic core to form a composite sandwich having a center plastic core and metal sides. The ice edge may be bonded to the foil by welding or brazing, then formed into shape to accept the plastic core. The plastic core may be injection molded directly into the formed metal structure, or bonded to the metal components in a secondary operation.

Abstract: A method of making an ice skate blade that comprises providing an upper member made of aluminum and a bottom member made of stainless steel. The upper member has a bottom portion comprising one of a recess and a projection and a top portion having attachment portions for allowing attachment of the upper member to a blade holder. The bottom member has a top portion comprising the other one of a recess and a projection and a bottom portion having a surface for contacting ice. The method further comprises joining the upper member and the bottom member together by registering the one of a recess and a projection of the upper member with the other one of a recess and a projection of the bottom member for making the blade.

Abstract: A runner and method of making a runner for mounting on a snow ski including a runner body fabricated of one piece of stamped metal which includes a central base portion and a pair of longitudinally extending runner portions which are bent downwardly from the base portions in laterally spaced relationship to one another. Carbide wear strips are secured to the lower edges of the runner portions, while the base portion 18 is fitted with mounting structure 48 which extends upwardly from the base portion and does not extend into the channel 36. The mounting structure 48 may be formed as one piece with the runner body 16 of the same material, has one or more tab features, and may be threaded and/or pierced to accommodate an associated net or mounting pin as desired for mounting the runner.

Abstract: A blade holder for holding an ice skate blade and for attachment to a skate boot. The blade holder comprises a body having a top portion for attachment to a skate boot and a bottom portion for receiving an ice skate blade. The body is at least partly made of clear material and defines a cavity. The blade holder also comprises a graphical element inside the cavity and visible through the clear material. An ice skate comprising such a blade holder and a method of customizing the appearance of the blade holder are also provided.

Abstract: A goalie skate having a skate boot comprising a thermoformed outer shell with a sole and an ankle portion for receiving the ankle of the foot, the ankle portion comprising medial and lateral sides for facing the medial and lateral malleoli respectively, the medial side comprising an upper edge that is a first distance away from the sole and the lateral side comprising an upper edge that is a second distance away from the sole, the first distance being greater than the second distance. By having a goalie skate boot that has the lateral upper edge located below the medial upper edge, the lateral outward flexion of the foot is eased when the goalie skate is in an angled position. The invention also relates to a goalie skate with a skate boot comprising an outer shell that is thermoformed such that it comprises an integrated toe portion, thereby eliminating the traditional toe cap.

Abstract: An exercise weight for a skate comprising a pair of similar elongated weight pieces. The skate comprises a boot, an elongated blade holder having spaced posts and a runner. The blade holder is secured to an underside of the boot and the runner is secured to blade holder. The weight is configured to be cooperatively releasably attached to the blade holder in a manner such that the weight pieces mateably conform to and engage with opposed side portions of the spaced posts below the boot and above the runner.

Abstract: A stabilizing training device suitable for use on an ice-skate is disclosed. The device provides a foot retaining portion and a stabilizing portion directly under the foot retaining portion. The unit is designed to provide at least partial resiliency to permit limited lateral movement in use. The device is positioned about the foot or footwear by positioning the former into the foot retaining area. A base extends between foot retaining members of the foot retaining area. The base contacts the sole of the foot or footwear and has, extending downwardly and outwardly therefrom, arms which provide for the stabilizing aspect when the device is in use.

Abstract: An ice skate strip-blade holder that provides a means to remove, replace, tension, and maintain tension in a strip-blade fastened and tensioned on the holder. In a preferred embodiment, the strip-blade holder assembly includes a front segment fixed to the skate plastic superstructure; a latched, pivoting rear segment arranged to apply and maintain tension in the strip-blade. In a preferred embodiment, the pivot and latch are positioned such that the pivot carries the majority of the tensile load maintained in the strip-blade and the latch carries a minor component of this tensile load. This arrangement provides for easy latch release. The latch provides release of the rear segment for subsequent pivoting and unhooking of the strip-blade for replacement.

Abstract: An ice skate runner for engagement in a blade holder of an ice skate, the blade holder having an opening defined along a bottom edge thereof and fastening means to retain the runner. The runner comprises an upper polymeric portion shaped to be partially received within the opening of the holder and defining a major part of the runner, a lower portion having a greater density than that of the upper portion and defining a lower blade surface for engaging the ice. At least one of the upper and lower portions is shaped to removably engage the fastening means.

Abstract: A skate having a skate boot with a non-lasted boot shell, the shell having a first non-lasted three-dimensional sub-shell and a second non-lasted three-dimensional sub-shell, the second sub-shell being interior to and adjoining the first sub-shell, the first sub-shell comprising a first material having a first density and the second sub-shell comprising a second material having a second density, the second density being less than the first density, the shell being shaped so as to have a heel portion, an ankle portion, a lateral portion, a medial portion, and a sole portion; and a ground-engaging assembly disposed on an underside of the skate. Additional sub-shells are possible. Methods of manufacturing the skate boot shell, including molding and build-up, are also disclosed.

Abstract: An ice skate whose blade is disposed at an angle not parallel to the longitudinal axis of the boot. The blade may be fixed in this position, or it may be switchable between the nonparallel orientation of the present invention and the parallel orientation typical of traditional ice skates. A pair of sideways-moving skates may be propelled by moving them in an oscillating motion.

Abstract: The invention relates to a skating sports device, in particular skating boot, comprising an exchangeable blade holder (14), connected to a boot by means of sole and heel plates (4 and 5). An exchangeable blade (1) may be clipped in the exchangeable blade holder (14), which is held under tension in the front and rear region by locking clip buttons (2) which may be operated without tools. A torsion duplex cross (3), formed by torsion and flexion bars (3a and 3b) absorbs the torsion and flexional forces occurring during skating and neutralizes the same.

Abstract: A skate blade has a front curved section having a front balance point, a rear curved section having a rear balance point, and a middle section having a center balance point. Each balance point is a point on the skate blade over which a skater's center of gravity lies depending on the skater's position. The skate blade is shaped such that the middle section is substantially flat. Additionally, the blade is shaped such that more of the blade extends away from a blade holder at the rear balance point than at the front balance point.

Abstract: A multi-blade ice-skate footwear includes a foot-retaining section with a substantially planar bottom surface, a first blade adjustably connected to an anterior portion of the bottom surface, and second and third blades adjustably connected to a posterior portion of the bottom surface and spaced from the first blade respectively. The ice-skate footwear includes a mechanism for selectively biasing the first blade along a first reciprocating linear path while simultaneously biasing the second and third blades along second and third reciprocating linear paths respectively.

Abstract: A blade for a skate includes a holder, a runner, and an attachment device. The holder includes a front section and a rear section where at least one of the front section and the rear section includes at least two, separate hollow regions and an aperture. The aperture extends through the holder between the at least two, separate hollow regions. The attachment device extends through a substantially solid portion of the holder between the two, separate hollow regions into the aperture and secures the runner to the holder. At least a portion of the attachment device used to secure the runner to the holder is accessible in the aperture.

Abstract: The present disclosure is directed to an ice skate including a boot, a separately formed casing, a blade, and a fastener. The boot includes a boot chamber for receiving a skater's foot. The casing includes an upper portion, a sole plate, and a blade holder. The upper portion defines a casing chamber for receiving the boot. In one example, the casing is plastic. The sole plate includes abutting toe, arch and heel areas and has a cantilevered connection to the blade holder. In this cantilevered connection, the toe and arch areas of the sole plate are supported by the blade holder and the heel area is unsupported by the blade holder. The blade holder defines a slot for selectively receiving the blade. The fastener removably secures the blade to the blade holder. In one example, the blade further includes a toe pick for use in figure skating.

Abstract: A skate boot includes a foot portion configured to receive and secure a foot of a wearer. The skate boot includes a first tendon guard positioned proximal an Achilles tendon of a wearer of the skate boot, the first tendon guard being connected to the foot portion at a first articulation point and adjacent the foot portion along a medial abutment line and a lateral abutment line. The skate boot may optionally include a second tendon guard connected to the foot portion at a second articulation point and to the first tendon guard, the second tendon guard covering the first articulation point. In at least one embodiment, an elastomeric band is connected to the foot portion and to the first tendon guard and configured to bias the first tendon guard to a closed position. In at least one embodiment, an electrical generator is provided to heat an ice skate interconnected to the boot.

Abstract: A skate assembly has a boot having a substantially completely open base with a sole plate of more rigid material than the boot secured over the open base. The base has an opening extending along at least substantially the entire length of the boot from the heel to the toe, with side rims extending along opposite sides of the base opening. The sole plate may be releasably or permanently secured to the boot.

Abstract: A hockey skate includes a system for adjusting the position of a blade holder on the sole of a hockey skate. The system allows for both toe in and toe out adjustment as well as movement relative to the centerline. The system allows a player to try various positions and determine which positions produce superior skating performance relative to his foot, ankle and leg alignment.

Abstract: Skate and blade assemblies (31) include a mechanism for the removal of the drag tooth (46) to facilitate replication, during sharpening, of the skating surface's (36) rocker profile throughout its entire length. With primary emphasis in avoiding not only the inevitable progressive degradation of the frontal portion of the skating surface but actual profile mutilation because of the projecting drag tooth. Such mutilation commonplace with large diameter grinding wheel types of sharpeners adversely affects a skater's performance, ruining a career opportunity and inevitably an expensive pair of figure skates. The primary component of the mechanism is an attachable-detachable toe-pick element (33) preferably including all or most teeth required of the toe-pick including the drag tooth. Exacting docking provisions (40-44) are provided for the toe-pick element (33) with the skate structure (32) or blade (62).

Abstract: A method of customizing a blade holder for an ice skate, comprising: (a) providing to a customer a blade holder body being at least partly made of a clear material and comprising a front pedestal with a front inner surface, a rear pedestal with a rear inner surface and a bridge portion interconnecting said front and rear pedestals, the front and rear inner surfaces defining respective front and rear cavities; (b) providing to the customer a plurality of graphical elements; (c) receiving from the customer an indication of a certain graphical element selected from the plurality of graphical elements; and (d) applying the selected graphical element to one of the front and rear inner surfaces such that the selected graphical element is visible through the clear material.

Abstract: A snow-sliding vehicle including a bearing rear runner and a directional front runner to which is connected a steering column pivoting in a sleeve firmly attached to the upper end of a stiff frame connecting both runners, and the lower end of which is attached to a supporting base surmounting the bearing runner and provided for supporting the feet of the user. The front portion of said base is connected to the bearing runner by a mechanical connection providing it with clearance ostensibly perpendicular to said runner controlled by a damping device.

Abstract: An ice skate chassis is configured so that a user can adjust the pitch of the skate chassis between a plurality of discrete pitch positions. The pitch is adjusted by locking the ice blade at a desired angle relative to a bladeholder of the chassis. The blade can be positively locked at a plurality of discrete, repeatable angle positions so that the angle will not slip or creep during skating.

Abstract: A runner and method of making a runner for mounting on a snow ski including a runner body fabricated of one piece of stamped metal which includes a central base portion and a pair of longitudinally extending runner portions which are bent downwardly from the base portions in laterally spaced relationship to one another. Carbide wear strips are secured to the lower edges of the runner portions, while the base portion 18 is fitted with mounting structure 48 which extends upwardly from the base portion and does not extend into the channel 36. The mounting structure 48 may be formed as one piece with the runner body 16 of the same material, has one or more tab features, and may be threaded and/or pierced to accommodate an associated net or mounting pin as desired for mounting the runner.

Abstract: An ice skate assembly for attachment to a boot has a skate blade and a blade heating arrangement mounted within a blade support. The blade is heated by a row of field-effect transistors carried on a circuit board or another type of heating element encapsulated on the top edge of the blade in an over-molded plastic strip which engages into a slot in the support as a wedged fit. The blade is attached by an inclined wedge member a screw for pulling the blade longitudinally of the blade and to draw the inclined wedge member into its receptacle. The battery pack is carried in the rear tower which is sealed against moisture penetration and includes two proximity switches for actuation.

Abstract: An ice skate boot comprising an outer shell made of thermoformable material. The outer shell is thermoformed such that it comprises a heel portion for receiving the heel of a foot, an ankle portion for receiving the ankle, medial and lateral side portions for facing the medial and lateral sides of the foot, and medial and lateral toe portions for covering the toes of the foot. The medial and lateral side and toe portions are thermoformed such that they define medial and lateral skirt portions extending downwardly therefrom and forming together a bottom portion for receiving an ice skate blade.

Abstract: An ice skateboard comprising a skateboard having a top surface, a bottom surface, side edges, and a front and back section, said ice skateboard having an ice blade assembly attached to the bottom surface, said ice blade assembly comprising a mounting plate having at least one integral ice blade that extends outwardly at substantially right angles from said mounting plate.

Abstract: A goalie skate having a skate boot comprising a thermoformed outer shell with a sole and an ankle portion for receiving the ankle of the foot, the ankle portion comprising medial and lateral sides for facing the medial and lateral malleoli respectively, the medial side comprising an upper edge that is a first distance away from the sole and the lateral side comprising an upper edge that is a second distance away from the sole, the first distance being greater than the second distance. By having a goalie skate boot that has the lateral upper edge located below the medial upper edge, the lateral outward flexion of the foot is eased when the goalie skate is in an angled position. The invention also relates to a goalie skate with a skate boot comprising an outer shell that is thermoformed such that it comprises an integrated toe portion, thereby eliminating the traditional toe cap.

Abstract: A blade guard for a runner blade of an ice skate. The blade guard includes a channel extending a distance between first and second ends. The channel has an open top and a bottom surface and first and second opposing side surfaces extending from the bottom surface to the open top. The blade guard also includes at least one recess disposed below the channel and extending a distance transverse to the distance of the channel. The at least one recess includes first and second countersink portions at opposite ends of the distance and a center portion. A first shoulder is defined between the first countersink portion and the center portion and a second shoulder is defined between the second countersink portion and the center portion.

Abstract: A method of customizing a blade holder for an ice skate, comprising: (a) providing to a customer a blade holder body being at least partly made of a clear material and comprising a front pedestal with a front inner surface, a rear pedestal with a rear inner surface and a bridge portion interconnecting said front and rear pedestals, the front and rear inner surfaces defining respective front and rear cavities; (b) providing to the customer a plurality of graphical elements; (c) receiving from the customer an indication of a certain graphical element selected from the plurality of graphical elements; and (d) providing one of the front and rear cavities with the selected graphical element such that the selected graphical element is visible through the clear material.

Abstract: A boot which has a tongue structure which includes at least first and second cables attached to the sides of the tongue, a guide channel associated with each cable, and a cable tensioning device connected to the cables and which is movable between first and second positions to respectfully tighten and loosen the cables. The tongue structure acts to maintain the foot in the boot and in a preferred embodiment, the tongue includes an outer somewhat rigid shell and an inner elastic layer.

Abstract: The invention relates to a skating sports device, in particular skating boot, comprising an exchangeable blade holder (14), connected to a boot by means of sole and heel plates (4 and 5). An exchangeable blade (1) may be clipped in the exchangeable blade holder (14), which is held under tension in the front and rear region by locking clip buttons (2) which may be operated without tools. A torsion duplex cross (3), formed by torsion and flexion bars (3a and 3b) absorbs the torsion and flexional forces occurring during skating and neutralizes the same.

Abstract: An ice skate comprising a blade and a blade holder. The blade holder providing decreasing, non rigid, and/or no lateral support in a rearward region of the blade so that it may facilitate increased or freer flexibility of the blade and improved maneuverability. The blade is rigidly laterally supported at a front end section of the blade holder and preferably also at a back end section of the blade holder so that it may facilitate efficient transfer of force between the skater and the blade. One or more non-rigid support members may be employed to control, absorb and/or cushion the flexing of the blade. The ice skate may be tuned to reflect the desired performance requirements of the individual skater and/or use.

Abstract: A method of manufacturing a blade of an ice skate includes the steps of providing a T-shaped stock piece of material having a plate and a leg extending from a center of the plate; machining the plate to form at least one mounting platform for connecting the blade to a skate shoe; machining the leg to form a skate body section that extends from the platform and includes a blade runner holder portion having a diamond cross-sectional shape with a downwardly directed slot. A separate blade runner is fixed to the blade runner holder portion within the slot and positioned for contacting the ice when in use. The blade runner is formed by providing a blade runner-shaped workpiece having a substantially constant thickness; using a vein cutting tool, and machining both lateral sides of an upper edge region of the blade runner-shaped workpiece simultaneously to form a thinner base region. The base region is sized to fit and be secured within the slot.

Abstract: An ice skate comprises a horizontal platform and a pair of opposing side brackets perpendicularly secured to an underside of the platform. A pair of opposing extension arms is pivotally engaged with each end portion of the side brackets, and an extender bracket is engaged with a center portion of the side brackets. Each extension arm has a torsion spring confined and arranged to enable the extension arm to pivot about the center axle within a certain range in tandem with the other of the pair of extension arms. A distal end of each extension arm has an axle non-rotatably engaged with a follower rotatably engaged in a vertical plane. Each follower is engaged with a horizontally elongated hole at front and rear end portions of the skating blade, and the extender bracket provides an additional follower engaged with a vertically elongated hole on a centerline of the skating blade.

Abstract: A hard surface slide for use as a recreational entertainment device that includes a slide member having a predetermined shape and a predetermined size. The slide member is formed from a flexible sheet of material having an upper surface and a bottom surface. An attachment device is engageable with the slide member for attaching the hard surface slide to a user's foot. A protective cover is disposed on the bottom surface of the slide member for protecting against mars on a hard surface floor due to friction with the bottom surface of the slide member.

Abstract: A skate boot for receiving the foot, the ankle and adjacent leg section of an intended user. The skate boot includes an upper. The upper defines a dorsal upper section and a substantially opposed plantar upper section, a rear upper section extending outwardly from and substantially peripherally to the plantar upper section and an opening allowing the user to insert the foot within the skate boot. The upper includes a deformable region for facilitating the elastic dorsiflexion of the upper between an initial upper configuration and a dorsiflexed upper configuration wherein the dorsal upper section is closer to the rear upper section than in the initial upper configuration, the deformable region being substantially more elastically deformable than adjacent upper portions of the upper and providing an elastic force biasing the upper towards the initial configuration upon dorsiflexion of the upper.

Abstract: For a glide sport article, especially an ice skate with a shoe body that is located on a chassis and that includes a cap-like shoe tip forming the toe area of the shoe body, a shoe body section forming the heel area and an ankle support, lacing on the shoe body section and a tongue located beneath the lacing, the shoe tip can be adjusted in a shoe body direction relative to the shoe body section on the chassis.

Abstract: An ice skate comprising an ice skate blade holder and an ice skate blade secured in a longitudinal recess of the ice skate blade holder. The ice skate blade has an ice contacting lower and upper curvatures so as to be positionally changeable in one of two alternative working positions with respect to the ice skate blade holder, wherein the ice skate blade is attached. The ice skate blade has also substantially parallel, opposed side surfaces intersected by at least two longitudinally spaced apart apertures coinciding with at least two longitudinally spaced apart, transversal openings in the ice skate blade holder. Use is made of restraining means inserted through at least two longitudinally spaced apart apertures and at least two longitudinally spaced apart, transversal openings, so as secure together the ice skate blade holder and the ice skate blade.

Abstract: A skating blade with a cross-section of three different portions. The upper portion is narrower, the middle portion is wider and the lower portion is trapezoidal to give improved ice penetration at the lower edges. The rocker is formed with two different curves. The front curve is defined by an arc of a circle and the rear curve is obtained by pivoting a radius forwardly along an arc of a circle and rearwardly along the rocker.

Abstract: Skate boot apparatuses, a skate, and a method are provided. A base including an upper face configured to receive a wearer's foot and a lower face configured to structurally support a skate mechanism is provided. An integral upper support is provided, the integral upper support extending upwardly from the base to a point above an ankle of the wearer, the integral support having a varying rigidity decreasing from a high rigidity near the base to a low rigidity near the point above the ankle of the wearer.

Abstract: There is disclosed an in-line skate with an adjustable length. The in-line skate includes a heel support, a toe support, a positioning element, a pushing element, and a switch. The heel support includes two parallel transverse grooves near a flank, a cavity near an opposite flank, a longitudinal groove between the transverse grooves and the cavity, and a slot therein. The toe support includes a slide put movably in the longitudinal groove and a series of pockets in the slide. The positioning element includes a button put movably in the cavity and two latches put movably in the transverse grooves of the heel support for entering a selective pair of the pockets of the toe support, thus keeping the toe support in selective one of several positions relative to the heel support. The pushing element is put movably in the cavity for pushing the button and hence the latches. The pushing element defines a tunnel.

Abstract: A ski having a central core, a lower reinforcement sub-assembly located beneath the core and resting on a gliding sole that is edged with two lateral running edges, and an upper reinforcement sub-assembly located above the core, and coated with a decoration layer, each of the reinforcement sub-assemblies having one or more layers, at least one of the upper reinforcement layers having a central portion, and at least one lateral portion. At least one of the reinforcement layers of the upper reinforcement sub-assembly has an asymmetrical structure in the area of its lateral portions, along at least a portion of its length. The invention also relates to a pair of skis, in which each of the skis is symmetrical to the other in mirror symmetry.