Ballet ski and method of manufacture

Abstract: A ballet ski 10 is provided for achieving enhanced stability when a skier is stationary or moving slowly. The bottom surface 18 of the ski 10 has a planar elliptical portion 42 centrally under the foot of the skier. Remaining portions of the bottom surface 18 are convex from front to rear and convex from side to side. Thus, a skier can easily roll from the planar ellipse 42 and into the curved portion to carry out selected ballet maneuvers. Preferably, the ski is formed from separate components configured to form air pockets 60 that reduce the weight of the ski. The ski may also include chamfers 36, 38 near the rear binding to enable a brake 32, 34 to rotate into the snow. Additionally, hook receiving apertures 40 may be formed through the rear end 14 of the ski 10. A pair of the skis 10 may then be used with straps 82 having hooks 84, 86 engageable in the apertures for conveniently suspending the skis 10 in a carrying position.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention. The invention relates to improvements in the field of ballet skis. The improvements relate to improved stability at low speeds, lighter weight, easier manufacturing, enhanced safety and easier transportation. 2. Description of the Prior Art. The typical prior art snow ski is very long, narrow and thin. In view of their narrow width and small thickness, the typical prior art snow ski has been fairly light weight despite its relatively long length. These prior art skis typically exhibit flexibility along their length, but assume a reversed camber in their unflexed condition. Thus, a ski that has its bottom placed on a flat surface will be supported by the front and rear of the ski. However, portions of the ski between the front and rear will be spaced upwardly from the flat surface. The bottom of the typical prior art snow ski is substantially flat from side-to-side at virtually all locations on the ski. The prior art snow ski originally was made from a unitary piece of wood. More recently, however, skis have been made from laminates, with layers being secured to one another by adhesive activated under significant heat and pressure. The bottom of the typical prior art snow ski includes metallic edges extending along the opposed sides of the bottom. The metallic edges typically have tabs secured by adhesive between layers of the laminate to anchor the edges into the bottom of the ski. Shorter versions of the above described prior art laminated snow skis have been developed primarily for novice skiers and children. These short prior art snow skis have width and thickness dimensions similar to the above described conventional prior art snow skis, and have the above described bottom that is flat from side-to-side. Bindings are used to releasably secure ski boots to the skis. The bindings include a pressure sensitive release that will separate the boot from the ski in response to forces encountered during a fall. The release of the ski substantially reduces the possibility of leg or knee injuries. Most prior art bindings include brakes that bite into the snow when the boot is released from binding. The brakes are located adjacent the top surface of the ski and generally behind the heal of the ski boot when the ski boot is locked into the binding. Upon release of the ski boot from the binding, the brakes move laterally beyond the sides of the ski and pivot downwardly into the snow. The length of prior art skis make them difficult to carry. Some skiers use the brakes to clamp the skis in bottom-to-bottom relationship. The interconnected skis can then be held in one hand while the skier carries additional equipment in the other hand. This interlocking of brakes can be difficult to achieve and difficult to maintain. Even a slight shifting of one ski relative to the other can cause the brakes to disengage and can make the carrying of skis cumbersome. The prior art also includes ski carriers in the form of plastic clamps that lockingly engage around a pair of skis. The clamps include a carrying handle and can greatly facilitate the carrying of prior art skis. However, the carrier must be stored while the skis are being used. Furthermore, the carrier does not avoid the inconveniences attributed to the considerable length of most prior art skis. The prior art also includes elongate flexible straps with metallic rings affixed to each end. Opposed ends of the strap can be looped through the rings, and the loops can be tightened around spaced apart locations on a pair of skis. The strap and skis then can be carried by hand or draped over the shoulder of the skier. These prior art straps are desirable in that they are inexpensive and can readily be collapsed and stored in the pocket while the skis are being used. However, the straps are not stable on the skis and the loops will eventually slide toward a central location near the bindings. Skiers have difficulty balancing the unstably suspended skis. Very effective prior art skis are shown in U.S. Patent No. 4,705,291 and in U.S. Design Patent No. Des. 339,398 both of which issued to Richard Gauer. The skis shown in U.S. Patent No. 4,705,291 and in U.S. Design Patent No. Des. 339,398 are shorter, wider and thicker than the conventional prior art ski described above, and are substantially inflexible. The bottom surface of the skis shown in U.S. Patent No. 4,705,291 and in U.S. Design Patent No. Des. 339,398 are continuously arcuately convex from front to rear. The ski shown in U.S. Patent No. 4,705,291 also is arcuately convex in a side-to-side direction at all locations along a centrally disposed, longitudinally extending strip of the bottom surface. However the sides of the bottom surface shown in U.S. Patent No. 4,705,291 are substantially flat in a side-to-side direction and opposed sides are generally colinear with one another at any cross-section. The ski shown in U.S. Design Patent No. Des. 339,398 does not include this side-to-side flattening near the side edges, and is continuously arcuately convex from side to side at all locations along the ski. The degree of side-to-side convexity in both of these patented skis varies along the length of the ski, such that a greater curvature exists at locations forward and aft of the foot. The skis shown in patents to Richard Gauer achieve the seemingly inconsistent objectives of providing enhanced mobility and increased control while performing various downhill ballet skiing maneuvers. These skis have enabled experienced skiers to perform beautiful artistic ballet movements while skiing down a steep slope, and also have enabled novice skiers, elderly skiers and handicapped skiers to effortlessly perform basic downhill skiing maneuvers. The skis shown in the patents to Richard Gauer are marketed under the trademark GAUER. Despite the many advantages of the skies shown in U.S. Patent No. 4,705,291 and U.S. Design patent No. Des. 339,398, improvements can still be made. For example, the side-to-side convexity at all locations along the length of the GAUER brand of ski can make skiers feel unstable when skiing slowly on packed snow or when standing stationary on packed snow. This may occur, for example, when the skier is moving into or through a ski lift line or when a skier is exiting a chair lift. At these locations, the snow is likely to be densely packed, and the skier may be standing substantially erect with weight balanced centrally over the skis while moving very slowly or standing still. Under these conditions, a novice skier may perceive a loss of balance in response to a shift of weight. The prior art GAUER brand skis also are considered to be heavy for their size. In this regard, the hollow foam-filled embodiments formed from two lateral channels as depicted in U.S. Patent No. 4,705,291 have been difficult to commercialize. Rather, the unitary injection molded ski depicted in the design patent has proved more commercially feasible. However, in view of the significant thickness, the unitarily molded ski is fairly heavy (3.5 pounds (≙ 1.6kg) each ski without bindings) and requires a fairly long injection molding cycle time. The width and thicknesses of the GAUER brand of skis also have made use prior art brakes difficult. In particular, prior art brakes will rotate into the top surface of the GAUER brand ski before moving laterally beyond the sides of the ski. Attempts have been made to bend the brakes outwardly into positions that will permit them to rotate fully. However, these revisions to the prior art brakes cause the brakes to project laterally even while the boots are in the bindings. Thus, a skier can readily catch one boot or ski on the inside brake of the opposed ski. Furthermore, the outwardly bent brakes do not dig deeply into the snow, and hence braking effectiveness is reduced. In addition to the long manufacturing cycle for cooling the thick plastic in GAUER brand skis, the installation of edges on the above described GAUER skis also has been time consuming. In particular, the above described GAUER skis are molded with corner channels for receiving metallic edges of generally rectangular cross-sectional shape. Holes are bored through the edges at approximately one inch spacings along the length of the edges. Screws then securely mount the edges into the corner channels in the prior art GAUER skis. Unlike prior art conventional skis, proper alignment of edges on the GAUER skis is important for optimum balletic maneuvering. In particular, the edges extend in tangential relationship to the arcuately convex plastic bottom of the prior art GAUER ballet skis. Improper alignment of the screws could position the metallic edges into non-tangential alignment with the bottom surface and/or could cause the screws to protrude from the plastic along the side. Acceptable results can be achieved only by employing skilled artisans to manually drill each hole and install each screw. The shorter length of the GAUER brand of skis intuitively should lead to easier carrying. However, the greater width and thickness makes it difficult to manually grasp these skis. Additionally, the prior art plastic carrying clamps are not dimensionally suited to the prior art GAUER brand of skis. The prior art straps described above can be used with GAUER brand of skis. However, these prior art straps have certain deficiencies as noted above. Additionally, the significant width and thickness dimensions of GAUER brand of skis make the looping required by the prior art straps even more difficult. Furthermore, these skis inherently leave little room aft of the bindings. Hence, there is only a very short space on the prior art GAUER brand skis that can be engaged by the loop of the prior art strap. Water skis bear some resemblance to snow skis, but are subject to significantly different forces during use. Nevertheless, the water ski shown in U.S. Patent No. 3,134,992 has a bottom surface which, at all locations along the ski is curved from front to rear and flat from side-to-side. The ski also includes plane surfaces around the bottom periphery to define a dihedral at the intersections with the flat bottom surface. The continuous front to rear curvature would not yield enhanced stability for a stationary or slow moving skier on snow. Furthermore, the bottom surface that is flat from side-to-side at all locations and the plane surfaces around the bottom periphery would not permit smooth flowing ballet movement on snow. The prior art has included many plastic forming techniques that have been used to make products other than skis. For example, blow molding and rotational molding have been used to make various hollow articles. Blow molding functions by closing a mold of selected shape around a tube of flowable plastic. Air pressure is then directed into the plastic tube and urges the plastic outwardly to conform to the precise shape of the mold. Blow molding is used, for example, to make plastic beverage containers. A low cycle time and a relatively inexpensive mold are among the many advantages of blow molding. However, blow molded plastic products are limited to very thin plastic walls that are likely to deform significantly in response to forces, such as forces encountered while performing balletic maneuvers on a ski. Rotational molding involves placing a flowable plastic inside a mold, and rotating the entire mold about an axis. Centrifugal force urges the plastic outwardly in the rotating mold, and hence causes the plastic to assume the shape of the mold cavity. Rotational molding can achieve slightly thicker walls than blow molding However, it is believed that the walls of a rotationally molded product are still too thin to withstand pressures encountered during skiing without significant deformation. The prior art also includes dual molding where a first portion of an object is molded and cooled. A second portion of the object is then molded to at least partly engage the first portion. This technique may be used to avoid overly complex and costly molds that would otherwise be required for producing a complicated part with a single mold. This technique also may be used where different types of plastic are needed to meet different performance specifications. For example dual molding may be used to make a laminated pipe fitting where the inner layer is contacted by a first chemical and the outer layer is contacted by a second chemical. It is the object of the invention to provide an improved ballet ski, which has an increased stability during standing and slow skiing and ensures a superior maneuverability during normal skiing. Further, it is an object of the invention to provide a method of manufacturing such an improved ballet ski. These objects are fulfilled by a ski having the features disclosed in claim 1 and both methods as disclosed in claims 10 and 11. Preferred embodiments are defined in the dependent subclaims. The ski preferably is formed from plastic material. However, metallic edges are securely affixed to the bottom surface of the ski adjacent the respective sides. The bottom surface of the ski is characterized by a substantially planar region that is approximately symmetrical with the pivot point. The pivot point is the location on the top surface of the ski about which the bindings are centered. The planar region on the bottom surface preferably is generally elliptical in shape, and may have a major axis aligned with the longitudinal axis of the ski. The planar region on the bottom surface of the ski preferably extends longitudinally a distance less than the length of the typical ski boot used with the ski. A preferred length for the planar region is approximately 6-10 inches (1 inch ≙ 2.54 cm). Regions of the bottom surface forwardly and rearwardly of the planar region are continuously arcuately convex from front to rear to achieve effective and efficient maneuverability with the ski. The planar region on the bottom surface of the ski further includes a width extending transverse to the longitudinal axis of the ski. The width of the planar region is less than the width of the ski. Portions of the bottom surface on either side of the planar region are convex from side-to-side. Furthermore, these portions of the bottom surface on either side of the planar region are continuously arcuately convex from front to rear. Portions of the bottom surface forwardly and rearwardly of the planar region are continuously convex from side to side. The degree of side-to-side convexity is greatest at locations on the bottom surface forward of the planar region. The symmetrically disposed planar region on the bottom surface of the ski achieves stability when a skier is standing still or moving slowly, and is particularly effective on densely packed snow. Thus, the planar region contributes to a sense of security when a skier is stopped in a ski lift line, when the skier makes an initial movement from a stopped position in a ski lift line, or when the skier is performing slow basic skiing movements. This slow skiing may be carried out when the skier is on the densely packed snow at the bottom of the slope or when the skier has exited a chair lift and is approaching the start of a downhill slope. However, the side-to-side convexity that exists between the planar region and the side edges of the ski ensures that the skier has superior maneuverability during normal skiing. Furthermore, the side-to-side convexity covers a longer distance at both the forward and rearward ends of the planar surface. The greater width of the side-to-side convex region at the forward end of the planar area enables the skier to roll the bottom surface of the skis efficiently into a turn, while the comparably greater width of the side-to-side convex region at the rear end of the planar area enables the skier to efficiently roll the bottom surface of the ski out of a turn. Throughout all such turns, the metallic side edges of each ski are effective in gripping snow or ice to provide exceptional control. Thus, the unique bottom surface of the ski ensures stability when the skier is stationary or moving slowly and provides controllable maneuverability at all other times. The ski may have at least one internal cavity, at least one internal support structure adjacent and/or defining the internal cavity and an outer shell surrounding both the cavity and the internal support structure. The ski may further include an internally disposed thin metal plate adjacent the outer shell. The outer shell is formed from a plastic selected for exhibiting desirable skiing performance and an appropriate aesthetic appearance. The internal support structure is in supporting engagement with at least selected portions of the outer shell to ensure structural integrity for the ski and to prevent significant deformation in response to forces exerted during skiing. The internal support structure and/or the metal plate may further provide an acceptable anchor for mounting bindings onto the skis. The internal cavity may comprise at least one air pocket defined by portions of the internal support structure and/or the outer shell. The internal cavity may be filled with a light weight material such as a foamed plastic. The light weight material may define an insert about which the internal support structure and/or the outer shell are subsequently formed. Alternatively, light weight filler material may be injected into a previously formed internal cavity in the outer shell and/or internal support structure of the ski. The internal support structure and the outer shell of the ski preferably are formed by injection molding, but blow molding, rotational molding, vacuum molding or compressed foam may be employed for at least the internal support structure. The outer shell and the internal support structure may be unitary with one another and may merely define functionally separate portions of a single unitarily molded portion of the ski, as explained further below. The ski may include locally chamfered regions at the interface of the top surface and the sides to accommodate movement of brakes on the bindings. The chamfers permit the brakes to pivot downwardly as they are translating laterally and into a braking disposition. Similarly, the chamfers permit the brakes to efficiently rotate upwardly and to translate inwardly as the boot is being engaged into the bindings. These chamfers avoid the need to deform the brakes, and hence ensure that the brakes are positioned to avoid contact with the opposing ski or boot during normal skiing. Each ski preferably includes a transversely aligned slot extending entirely therethrough at a location near the extreme rear end of the ski. The skis may further be used in conjunction with a strap having hooks attached to opposed ends. The hooks are releasably engageable in the slots of the skis to permit convenient carrying of the skis. The invention is further directed to a method for making the above described skis. One preferred method includes an initial step of forming an internal support structure. The internal support structure may be hollow, and hence may define and include the internal cavity of the ski. The internal support structure may be formed by blow molding, rotational molding or injection molding. A preferred method includes separate injection molding of upper and lower halves of the internal support structure and then securing the halves together to define the internal cavity. The internal support structure may be molded to include corrugations or ribs at internal positions on the ski for further contributing to structural support and dimensional integrity during skiing. These corrugations or ribs may be disposed to coincide with locations used for anchoring bindings on the ski. The outer surface of the internal support structure may be molded to facilitate molded plastic engagement by the outer shell as explained herein. The method may proceed by placing the internal support structure into the mold for the outer shell. Portions of the internal support structure may define positioning legs that extend into contact with portions of the injection mold to precisely position the internal support structure relative to the outer shell. Plastic for the outer shell then may be injected about the internal support structure. The above described methods may further include mounting metal edges into side regions of the bottom surface of the ski. The mounting of the edges may be by the above described drilling and screwing procedures. However, the mounting of edges may be carried out by snapping edges into the ski. In this latter regard, the bottom surface of the ski may be formed with a corner channel for receiving the metallic edges. The ski may further be molded to include a locking groove extending parallel to the adjacent side of the ski and toward the top surface of the ski. As a further manufacturing step, an anchoring groove may be machined into the ski after completion of the molding processes. The anchoring groove may extend into the corner channel substantially parallel to the bottom surface of the ski. This additional manufacturing step may be carried out by a router-like tool with guides for precisely tracking the arcuately convex bottom surface of the ski. The metal edge may include a generally rectangular cross-sectional portion having two flanges projecting therefrom. One flange may be dimensioned to be inserted into the machined anchoring groove in the bottom surface of the ski. The other flange may be dimensioned to snap into the molded locking groove after sufficient insertion of the first flange into the machined anchoring groove. This slidable and snapped insertion of the edges into the grooves can completely avoid the manufacturing inefficiencies of the above described drilling and screwing processes of the prior art ballet skis, while further avoiding the difficulties associated with laminating and gluing the edges into the bottom surface for a conventional prior art ski. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a pair of skis in accordance with the subject invention suspended from a carrying strap and being carried by a skier. FIG. 2 is a top plan view of a ski in accordance with the subject invention. FIG. 3 is a side elevational view of the ski. FIG. 4 is a bottom plan view of the ski. FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 2. FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 2. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 2. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 2. FIG. 9 is a cross-sectional view similar to FIG. 5, but showing a second embodiment. FIG. 10 is a cross-sectional view taken along line 11-10 in FIG. 9. FIG. 11 is a top plan view of a portion of the bottom half of an alternate internal support structure. FIG. 12 is a cross-sectional view similar to FIG. 9, but showing the third embodiment of the ski. FIG. 13 is a cross-sectional view similar to FIG. 9, but showing a fourth embodiment of the ski. FIG. 14 is a cross-sectional view similar to FIG. 9, but showing a fourth embodiment of the ski. FIG. 15 is an end elevational view of a metallic edge for use with a ski groove as shown in FIGS. 13 and 14. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Skis in accordance with the subject invention are identified generally by the numeral 10 in FIGS. 1-14. With reference to FIGS. 2-4, each ski 10 includes opposed front and rear ends 12 and 14 respectively, opposed top and bottom surfaces 16 and 18 respectively and opposed sides 20 and 22. The top surface 16 of the ski 10 includes indicia for identifying the point 24 about which the bindings and ski boots are centered. This centering point is common in prior art skis as well. A set of prior art bindings 26 is securely mounted to top surface 16 of ski 10 at a location appropriately centered on the centering point 24. The bindings 26 include a front binding 28 and a rear binding 30. The rear binding 30 is equipped with a pair of brakes 32 and 34 respectively. The brakes 32 and 34 are driven by the rear binding 30 from a braking position as illustrated in FIG. 2 to a skiing position as illustrated in FIG. 3. In the skiing position of FIG. 3, the brakes 32 and 34 are rotated upwardly and are retracted inwardly to lie substantially entirely above top surface 16 and between sides 20 and 22. Upon release of a ski boot from the rear binding 30, the brakes 32 and 34 will translate laterally away from one another, and will simultaneously rotate downwardly so that portions of each brake 32 and 34 will lie below the bottom surface 18 of the ski 10. This translational and pivoting movement of each brake 32 and 34 is accommodated by a pair of chamfers 36 and 38 formed in each ski 10. The chamfers 36 and 38 lie at the interface of the top surface 16 with the respective sides 20 and 22 of the ski 10. Furthermore, the chamfers 36 and 38 are disposed rearwardly of centering point 24 and generally aligned with the rear binding 30. The chamfers 36 and 38 are configured and aligned to permit free rotation of the brakes 32 and 34 from the FIG. 3 skiing position to the FIG. 2 braking position and vice versa. The ski 10 is characterized by an aperture 40 extending entirely therethrough from the top surface 16 to the bottom surface 18 at a location near the rear end 14 of the ski 10. The apertures 40 enable a pair of skis 10 to be used with a carrying strap 82 as illustrated schematically in FIG. 1. More particularly, the carrying strap 82 includes end hooks 84 and 86 which are dimensioned to releasably engage in the aperture 40 of a ski. Thus, the strap 82 and the skis 10 mounted thereon can be suspended around the neck or over the shoulder of a skier for convenient transportation. This convenience is enabled by the desirably short length (e.g., 80-100 cm) of the ski 10. The bottom surface 18 of the ski 10 is characterized by a substantially elliptically shaped planar portion 42. The planar elliptical portion 42 has a major axis of symmetry aligned substantially parallel to the longitudinal axis of the ski 10 and defining a length "L" which is less than the length of a typical ski boot to be mounted on the top surface 16 of the ski 10. More particularly, a preferred length "L" for the planar ellipse 42 is approximately eight inches. The planar elliptical portion 42 also has a minor axis of symmetry which intersects the major axis of symmetry at a location approximately registered with the centering point 24 shown in FIG. 2. The minor axis of symmetry defines a width "W" for the planar ellipse 42 approximately equal to 60°-75° of the overall width of the ski at that location. In a preferred embodiment, the planar ellipse 42 defines a width "W" approximately equal to 2.5 inches, while the ski 10 defines an overall width at that location of centering point 24 approximately 3.5 inches. As shown in FIG. 3, the bottom surface 18 of the ski 10 in continuously arcuately convex from front to rear at locations disposed both forwardly and rearwardly of the planar ellipse 42. Additionally the bottom surface 18 is continuously arcuately convex from front to rear locations on either side of the planar ellipse 42. As shown in FIGS. 4-6, portions of the bottom surface 18 on either side of the planar ellipse 42 extend convexly upwardly. The side-to-side dimensions of these convex regions on either side of the planar ellipse 42 are shortest at the locations aligned with minor axis of symmetry, as shown in FIGS. 4 and 5. The width of the planar ellipse 42 decreases both forwardly and rearwardly from the minor axis of symmetry. As a result, the side-to-side dimension of these convex regions near the forward or rearward ends of the planar ellipse 42 become increasingly greater. As shown in FIG. 8, the side-to-side convexity at locations forwardly of the planar ellipse 42 is defined by a smaller radius of curvature portion disposed in a central location on the bottom surface 18 and extending through a width of approximately 25%-40%, and preferably 33%, the width of the ski 10. The sides of the bottom surface 18 extend laterally and upwardly as tangents to the curved central portion at locations forward of the planar ellipse. The bottom surface 18 has its greatest side-to-side convexity at the location shown in FIG. 8. The side-to-side convexity rearward of the planar ellipse 42 includes a central curved portion and tangents extending laterally therefrom similar to FIG. 8. However the curved central portion is slightly flatter than in FIG. 8, and hence the degree of side-to-side convexity is less. The side-to-side convexity also flattens out somewhat at the extreme forward end of the ski 10. As depicted clearly in each of FIGS. 4-7, the bottom surface of the ski 18 is characterized by well defined metallic side edges extending substantially the entire length thereof. The metallic edges 44 and 46 define widths of approximately ¼-⅜ inch. The metallic edges 44 and 46 are securely held in position by a plurality of screws 48 extending upwardly for secure anchoring into the ski. The edges have side-to-side alignments substantially tangent to the side-to-side convexity of the bottom surface 18 at all locations therealong. Thus, the bottom surface of the ski can efficiently and smoothly roll into one of the metallic side edges 44 or 46 as the skier is turning. However, the extreme corner defined by each edge, as shown in FIGS. 5-8, enables the skier to exercise exceptional control during such turns. As shown most clearly in FIGS. 4-7, the planar ellipse 42 is, at all locations, spaced inwardly from metallic edges 44 and 46. The bottom surface configuration depicted in FIGS. 4-7 yields several performance advantages. First, the planar ellipse 42 provides a sufficiently large platform to give stability to even a novice or elderly skier while standing still, commencing short movements from a standstill, or moving slowly. These movements are likely to occur after a skier finishes a downhill run, as a skier is standing in or moving through a ski lift line or when the skier is moving slowly after leaving a chair lift and preparing to commence a downhill run. The stability enabled by the planar ellipse 42, however, does not affect downhill skiing performance in any measurable way. In particular, the planar ellipse 42 is spaced inwardly from the sides 20 and 22 of the ski and from the metallic edges 44 and 46. Hence, even at the widest portion of planar ellipse 42, the skier can still rock onto the side-to-side convex portions between the planar ellipse 42 and the sides 20 and 22 of the ski. Furthermore, the skier typically will rock onto portions forwardly or rearwardly of the planar ellipse 40 and 42 while negotiating turns during downhill skiing. The width of the planar ellipse 42 becomes narrower at such forward and rearward locations, with the side-to-side convexity occupying greater dimensions on the ski. Hence, the skier can easily rock onto these wider side-to-side convex portions during a skiing maneuver. Furthermore, as shown in FIG. 8, the ski exhibits continuous side-to-side convexity at locations forwardly and rearwardly of the planar ellipse 42. Weight is shifted toward these locations during skiing, and hence turns and spins can be completed easily with the ski 10. The slightly flatter convexity at the rear end helps prevent uncontrolled spinout at the end of a turn. With reference to FIG. 9, the ski 10 is formed to include an internal support structure 50 formed from upper and lower injection molded halves 52 and 54 which are secured together. The upper and lower halves 52 and 54 are provided with inwardly facing reinforcement ribs 56 and 58 respectively disposed for supporting engagement with one another on the assembled internal support structure 50. Reinforcement ribs 56 and 58 are disposed to define internal cavities 60 between the upper and lower halves 52 and 54. More particularly, the ribs 56 and 58 may extend longitudinally to define elongate cavities 60 as shown in FIGS. 9 and 10. Alternatively, the ribs 56, 58 may define a honeycomb, as shown in FIG. 11. The opposed upper and lower halves 52 and 54 are securely locked into the assembled condition shown in FIG. 9. More particularly, the lower half 54 is molded with a plurality of locking apertures 62 in the upper surface thereof, and the upper half 52 of the internal support structure 50 is provided with a plurality of locking pins 64 disposed and dimensioned for locking into the apertures 62 to securely hold the opposed halves 52 and 54 of the internal support structure 50 in an assembled condition. The lower half 54 of the internal support structure 50 is provided with a plurality of bottom positioning legs 66 projecting downwardly therefrom and with a plurality of lateral positioning legs 68 projecting transversely therefrom. The lateral positioning legs 68 are disposed to lie on the parting line of the mold used to form the lower half 54 of the internal support structure 50. The upper half 54 of the internal support structure 50 similarly is provided with a plurality of top positioning legs 70 and lateral positioning legs 72. The positioning legs 66-72 are used to precisely position internal support structure 50 within a mold cavity used to form an outer shell as explained further below. The bottom positioning legs 66 preferably are slightly shorter (⅛" - 3 / 16 ") than the top positioning legs 70 (¼" - ⅜"). Thus, the outer shell formed around the internal support structure 70 will be thicker in portions adjacent the top surface 16 of the ski 10. The greater thickness can be helpful for ensuring a secure mounting of bindings 26 onto the ski 10. The lateral legs 68 and 72 may be disposed to register with one another or may be offset from one another. The outer surface regions of the internal support structure 50 preferably have a textured finish to permit gripping by the outer shell. The assembled internal support structure 50 is positioned within an injection mold cavity having a shape selected for the desired external configuration of the ski 10 as described above and in the referenced Gauer patents. Precise positioning is ensured by the positioning legs 66-72. Certain positioning legs may be dimensioned to engage apertures in the mold to hold the internal support structure 50 in position prior to closing the mold. The mold cavity is then filled around the internal support structure 50 to form an outer shell 74. In a second embodiment, additional strength may be provided in proximity to the top surface 16 of the ski 10. For this embodiment, a thin metallic plate 76 may be positioned on a top side 78 of the upper half 56 of the internal support structure 50 as shown in FIG. 12. The plate 76 may have a thickness of approximately ⅛" - 3 / 16 " and may extend over portions of the ski 10 to which the binding 76 may be mounted. The plate 70 has apertures that permit the top positioning legs 50 to pass therethrough. The ski 10 offers several significant manufacturing efficiencies. For example, the internal cavities 60 result in a significant weight reduction for the finished ski 10. Additionally, although the ski 10 requires more molds than the prior art skis identified above, all molded parts have relatively thin walls, and a much faster cycle time can be achieved. In an alternate embodiment of the ski 10, the internal support structure 50 may be unitarily molded by, for example, blow molding or rotational molding. These molding techniques also lead to fairly short cycle times and enable a hollow product to be formed. However, blow molding and rotational molding are not well suited to the formation of precise positioning legs 66-72, nor the formation of internal ribs 62 for reinforcement. These potential draw backs of blow molding and rotational molding can be offset by selecting wall thicknesses to provide adequate structural support without reinforcing ribs and to provide separate positioners for accurately locating the internal reinforcement within the mold cavity used to form the outer shell 74. For example, positioners may be part of the mold used to form the outer shell 74. This necessarily would leave holes in the outer shell 54 that would require filling after removal of the ski 10 from the mold. As a further alternate, sandwich molding may be employed where two unmixable plastics may be injected into the same mold. A first plastic may be foamed to define the internal support structure 50 and with bubbles in the foam defining the internal cavity. The second plastic will not mix with the foam and will be injected to form the outer shell 74. Third and fourth embodiments of the ski 10 are illustrated in FIGS. 13 and 14. The ski 10 is similar to the ski in the preceding figures in that it includes internal cavities 60. In this embodiment, the outer shell 74 is formed from opposed top and bottom halves 90 and 92 and the internal support structure is defined as a unitary projection 94 from the bottom half 92. The lower half 92 is formed with a recessed seat into which the upper half 90 is received. The upper half 90 of the outer shell 74 may be recessed to form a protected region for receiving an applique 96 with safety information or decoration. This construction is similar to the construction depicted in FIGS. 5-8 with a few notable exceptions. First, the seam between upper and lower halves is completely surrounded and protected. Second to achieve larger voids and hence lighter weight without reducing strength, the ski 10 may further include a metal plate 91 between the opposed top and bottom halves 90 and 92 of the outer shell 30 as shown in FIG. 13. Third, to avoid costs, time and potential difficulties associated with sonic welding, the ski 10 is provided with mechanical connectors in the form of pins 98 force fit into apertures 100, 102 as shown in FIG. 13 or screws as shown in FIG. 14. As shown in FIG. 8, the top and bottom halves 90 and 92 have apertures 100 and 102 respectively, and the pins are separate members. In other embodiments, however, the pins may be unitarily molded with either the top or bottom half 90 or 92, and may be disposed and dimensioned to be lockingly received within the apertures 100, 102 in the other half. The ski 10 of the subject invention includes metal edges 110 secured to portions of the bottom surface 18 adjacent the sides 20 and 22 of the ski 10. The metal edges 110 are formed from strips of metal extruded or cold rolled to the shape depicted in FIG. 15. More particularly, each metal edge 110 includes a bottom surface 112 and a side surface 114 which meet at a corner 116. Each edge 110 further includes a top mounting surface 118 and a side mounting surface 120 which seat against correspondingly configured and dimensioned surfaces on the ski 10. Each metallic edge 110 further includes a vertical locking flange 122 and a horizontal anchoring flange 124. The horizontal anchoring flange 124 extends substantially parallel to the bottom surface 112 and the top mounting surface 118, and substantially in the same plane as the top mounting surface 118. The vertical locking flange 122 lies substantially in the plane of the side mounting surface 120 and substantially parallel to the side mounting surface 120 and the side surface 114. To accommodate the edge 110, the ski 10 is molded with a corner channel 126, having a horizontal mounting face 128 and a vertical mounting face 130 as shown in FIG. 13. Additionally, the ski 10 is molded to include a vertical locking groove 132 extending substantially vertically and continuously from the vertical mounting edge 130. The vertical locking groove 132 is readily moldable when the parting line between opposed halves of the injection mold extend substantially parallel to the top surface 16 of the ski 10. After removal of the ski 10 from the mold, and after appropriate cooling, a router-like tool is used to machine a horizontal anchoring groove 134 into the plastic of the ski 10 and parallel to portions of the bottom surface 18 adjacent the corner channel 126. In this regard, the bottom surface 18 of the ski is arcuately convex at most locations, and hence the channel 134 follows the convex shape. Additionally, the horizontal groove 134 is disposed to substantially align with the horizontal mounting surface 128 of the corner channel 126. The edge 110 is mounted into the corner channel 126 by urging the horizontal flange 124 into the horizontal groove 134 that had been machined into the plastic of the ski 10. More particularly, this movement of the metal edge 110 is carried out to move the edge 110 from the side of the ski toward the middle. This mounting of the metallic edge 110 will initially cause a deflection about the horizontal anchoring flange 124 as the vertical locking flange 122 slides along the horizontal mounting surface 128 of the corner channel 126. After sufficient movement, however, the vertical locking flange 122 will align with the vertical locking groove 132 and will snap into engagement. This secure retention of the flanges 122 and 124 in the grooves 132 and 134 respectively will securely retain the edge 110 in the corner channel 126 without screws as in the prior art Gauer skis and without adhesive and lamination as in the prior art conventional skis. While the invention has been described with respect to a preferred embodiment, it is apparent that various changes can be made without departing from the scope of the invention as defined by the appended claims.

Claims: A ski having opposed front and rear ends (12, 14), opposed sides (20, 22), a top surface (16) and a bottom surface (18), said bottom surface (18) including metallic edges (44, 46, 110) adjacent said sides (20, 22), said bottom surface (18) including an elliptically shaped planar portion (42) intermediate said metallic edges (44, 46, 110), said bottom surface (18) further being convex from front to rear at all locations spaced from said planar portion (42) and being convex from side-to-side at all locations spaced from said planar portion (42). A ski according to claim 1, wherein said elliptically shaped planar portion (42) has a center, said ski (10) further comprising bindings (26) mounted on said top surface (16), said bindings (26) being centered about a point (24) registered with the center of said elliptically shaped planar portion (42) on said bottom surface (18). A ski according to claim 1 or 2, wherein said elliptically shaped planar portion (42) defines a non-circular ellipse having a major axis aligned longitudinally on said ski (10). A ski according to any of claims 1-3 comprising an internal support structure (50, 94) and an outer shell (74) surrounding said internal support structure (50, 94), said internal support structure (50, 94) defining a plurality of internal cavities (60) within said ski (10). A ski according to claim 4, further comprising an internally disposed metallic plate (76, 81). A ski according to claim 4 or 5, wherein the internal support structure (50) comprises upper and lower halves (52, 54) secured together and defining ribs (56, 58) and said internal cavities (60) therebetween, said internal support structure (50) having an outer surface with a plurality of outwardly projecting positioning legs (66-72), said outer shell (74) being unitarily formed around said internal support structure (50) and surrounding and engaging said positioning legs (66-72). A ski according to claim 4 or 5, wherein said outer shell (74) comprises upper and lower sections (90, 92), said internal support structure (94) being unitary with one of said upper and lower sections (90, 92) and being dimensioned and configured for engaging the other of said upper and lower sections (90, 92) of said outer shell (74) and for defining said internal cavities (60). A ski according to claim 7, wherein said lower section of said outer shell (74) includes a recessed seat in an upper portion thereof, said upper section (90) of said outer shell (74) being securely received in said seat of said lower section (92). A ski according to any of claims 1-8, said ski (10) having an aperture (40) extending entirely therethrough from said top surface (16) to said bottom surface (18) at a location in proximity to said rear end (14), said aperture (40) being dimensioned for receiving at least a portion of a carrying strap (82). A method for manufacturing the ski of any of claims 4-8, said method comprising: molding said internal support structure (50) defining said internal cavities (60) therein; molding said outer shell (74) around said internal support structure (50); and securing said metallic edges (44, 46, 110) to said outer shell (74). A method of manufacturing the ski of any of claims 1-3, said method comprising the steps of: molding a first ski section (92) having a first external surface region, at least one reinforcing rib (94), at least one open cavity (60) between said reinforcing rib (94) and said external surface region of said ski (10) and a seat adjacent said cavity (60) and said rib (94); molding at least one second ski section (90) having a second external surface region; securing said second ski section (90) to said seat of said first ski section (92) such that said second ski section (90) encloses each said cavity (60) and engages said reinforcing rib (94) of said first ski section (92); and affixing said metal edges (44, 46, 110) to selected locations on said external surface region. The method of claim 10 or 11, wherein the ski (10) has opposed top and bottom surfaces (12, 14) and opposed sides (20, 22), said method comprising the steps of: molding corner channels (126) in portions of said ski having said bottom surface and molding locking grooves (132) extending into the respective corner channels (126) and aligned substantially parallel to the sides (20, 22); machining anchoring grooves (134) extending into portions of the respective corner channels (126) aligned substantially parallel to said bottom surface (18); providing metal edges (120) having anchoring flanges (124) dimensioned for insertion into one said anchoring groove (134) and having locking flanges (122) dimensioned for insertion into one said locking groove (132); inserting said anchoring flange (124) into said anchoring groove (134) from said side of said ski; and snapping said locking flange (122) into said locking groove (132) for securely engaging each said metal edge (110) into said corner channel (120) of said ski (10).

Inventors: FEKETA JAMES, GAUER RICHARD, FEKETA, JAMES, GAUER, RICHARD
Applicants: GSI INC, GSI, INC.
Application year: 1995
Main classification: A63C5
IPC codes: A63C5