CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Serial No. 60/158,574 which is entitled INTEGRAL SUSPENSION SYSTEM FOR SKIS and was filed on Oct. 7, 1999. 
    
    
     FIELD OF THE INVENTION 
     This invention pertains to a full suspension system for skis which allows for total edge control, while significantly dampening impacts and vibration. 
     DESCRIPTION OF THE RELATED ART 
     Skiing is inherently dangerous and hard on the body. When skiing at any speed, regardless of terrain, the upper body is subjected to numerous jolts and impacts which the legs cannot effectively deal with. Such impacts engender fatigue in the skier, and create chatter and loss of contact with the snow. This alters performance significantly, and often culminates in physical injury. 
     Since impact force is the overall force divided by the time of force application, the ideal way to attenuate impact forces is by prolonging, and thereby lessening, the immediate force of impact. This is most efficiently done by allowing for “travel” anywhere between the ski and the upper body. The skier&#39;s legs do some of this work, but peak impact loads are more efficiently dampened somewhere between the binding and the boot, not via the skier&#39;s legs. A system which offers vertical travel concurrent with positive edge control is optimal. 
     Thus far all prior art shock absorbing elements for skis either do not provide positive edge control (by having mechanisms which allow for vertical travel, but poor control of lateral flexing), or do no more than dampen vibrations (by controlling lateral flexing but not allowing for vertical travel). 
     For example, U.S. Pat. No. 4,896,895 to Bettosini describes a plate of metal alloy sandwiched over a layer of absorbent material, and fastened to the ski. This approach allows for positive edge control, but doesn&#39;t offer the vertical travel necessary to truly absorb peak impact forces. In order for it to allow for positive edge control, said metal alloy plate must be very rigid both laterally and longitudinally. This has a negative affect on the natural flexing of the ski, creating a “flat spot” under the ski which drastically affects edge control. Even if this version was integrated into the ski a flat spot would ensue, as the longitudinal sheer forces exerted with ski flexing are not dampened appropriately by a top plate which is both rigid and adjacent to (as opposed to within) the ski&#39;s arc of flex. In addition, the attachment means are inherently subject to sticking when subjected to longitudinal sheer forces, thus affecting overall flexing of the plate in relation to the ski. There are a variety of other designs based on this approach which also do nothing to provide vertical travel, while suffering from the same drawbacks. 
     U.S. Pat. No. 4,139,214 to Meyer describes an articulating system based on a hinge positioned in front of the boot which allows for significant vertical travel, but unfortunately, also significant lateral rotational flexing. Correct transmission of lateral forces necessary for positive edge control is virtually impossible with such a system, as the front hinge is the only rigid transverse engagement with the ski. Torsional forces applied to the bindings thus engender lateral rotational flexing of the entire binding plate relative to the ski, significantly inhibiting positive edge control. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the deficiencies of the prior art by incorporating a plurality of linkage mechanism between the ski binding and the ski which effectively allow for optimum absorption of impact forces, while maximizing edge control. In this invention, upon impact, the top plate flexes vertically towards the ski, while maintaining lateral rigidity. 
     REFERENCE SYMBOLS IN DRAWINGS 
       2  Ski 
       4  Boot 
       6   a  Binding Toe 
       6   b  Binding Heel 
       8  Top Plate 
       10  Middle Plate 
       12  Ski Plate 
       14  Formed Rod Linkages 
       16  Panel Linkages 
       18  Substantially Rigid Body 
       20  Resilient Elements 
       22  Longitudinal Axes 
       24  Cylindrical Holes 
       26  Flexural Coupling 
       28   a  Formed Rod Flexure Axes (top) 
       28   b  Formed Rod Flexure Axes (bottom) 
       30   a  Panel Linkage Flexure Axes (top) 
       30   b  Panel Linkage Flexure Axes (bottom) 
       32  Replaceable elastomer cartridges 
       34  Primary Flexure axes 
       36  Secondary Flexure Axes 
       38  Tertiary Flexure Axes 
       40  Quaternary Flexure Axes 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a preferred embodiment of the invention. 
     FIG. 2 is an enlarged view of the embodiment shown in FIG. 1 inside circle  2-2.    
     FIG. 3 is a top plan view of the embodiment of FIG.  1 . 
     FIG. 4 is a side elevation view of the embodiment of FIG. 3 integral with a ski with bindings mounted. 
     FIG. 5 is a side elevation view of an alternative embodiment of the present invention. 
     FIG. 6 is a side elevation view of an alternative embodiment of the present invention. 
     FIG. 7 is a side elevation view of an alternative embodiment of FIG. 6 integral with skis, with bindings attached. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first embodiment of the present invention is shown in FIGS. 1-3. Suspension system includes a top plate  8  coupled by a plurality of panel linkage mechanisms  30   a  and  30   b  (collectively, linkage mechanisms  30 ). A plurality of resilient elements  20  are located between the top plate  8 , the ski plate  12 , and panel linkage mechanisms  30 . FIGS.  1 - 4  illustrate this type of panel linkage mechanisms. This design allows the top plate  8 , linkage mechanisms  30 , and ski plate  12  to be fabricated as a single body. The resulting panel linkages  16  have a substantially rigid body  18  and flexural couplings  26   a  and  26   b  (collectively  26 ) located at opposed margins of the rigid body  18  which are coupled to the top  8  and ski  12  plates. These flexural couplings  26  define flexure axis  30   a  and  30   b , respectively, where the flexural couplings  26  couple to the top  8  and ski  12  plates. The flexural couplings  26  allow the respective plates,  8  and  12 , to pivot about respective flexure axes  30   a ,  30   b . Thus the top plate  8  pivots about the rigid body  18  of the panel linkages  16  along the flexure axes  30 . 
     These flexible profiles may be molded, milled, extruded, or fabricated in any manner which allows for hinging motion of the rigid body  18  of the linkage mechanisms  16  via the flexural couplings  26 . This dynamic hinging is known in the industry as a “living hinge”. Plastics (generally of the softer variety such as UHMW, polypropylene, or Hytrel) are the preferred materials, but other materials may be suitable—essentially any material that provides low creep, good kinetic memory, pliability, and appropriate lateral rigidity suffice. Being that the flexural couplings are of lesser thickness than the rest of the shape, a hinging dynamic automatically occurs in this area. All other parts of the panel linkages  16  remain substantially unflexed via the rigid body  18 . 
     As shown in FIGS. 1-6, the flexure axis  28 ,  30  of this embodiment are generally transverse to the longitudinal axis  22  (see FIG.  2 ). They may be spaced at varying intervals, but are preferably placed at around 1.5 inches apart. The vertical height of the panel linkages  16  may vary widely, but are generally preferable at around 0.4 inches. 
     Resilient elements  20  such as elastomers, gels, or air bladders (and various combinations thereof) may be incorporated in the present invention. The inside of the top plate  8  and ski plate  12  may be indented in order to allow for fore-aft rolling of relatively high durometer elastomer cylinders or spheroidal elastomers. If air bladders are used as the resilient elements  20 , they may incorporate an integral valve such as those found on soccer balls, which allows for easy adjustment of pressure. Various degrees of bladder wall elasticity and inflation pressure can be used to customize the right performance characteristics for each skier depending on his/her weight, ski conditions, and ability. Open cell foam may be used inside the air bladders as a means of dampening. 
     If the resilient elements  20  are made from elastomer material, they may take the form of replaceable elastomer cartridges  32 . This allows for infinite adjustment options, and insures that the damping quality is always optimal, insofar as when one elastomer is worn out, it is simply replaced. 
     The entire space between top  8 , ski  12 , and middle plate  10  should be filled with some kind of elastomer (or air bladder) not only to provide damping, but to keep snow from being packed into this area. As such, a relatively high density (shore oo of 60 of more) replaceable elastomer cartridge  32  can be used in conjunction with a relatively low-density resilient element (shore oo of 10-60). This allows for progressive damping, while still allowing for adjustability, and serving as a snow barrier. 
     FIG. 3 illustrates how the panel linkage  16  embodiment appears when mounted on skis with bindings. Although it&#39;s possible to have the panel linkages  16  run the entire length of the top  8  and ski  12  plates, it is not necessary. This illustration demonstrates how the panel linkages can be arranged in the forward portion (just under the binding toe  6   a ) and rear portion (just under the binding heel  6   b ). Such an arrangement allows for lighter weight, while retaining the same performance characteristics. The top plate  8  must connect the front and rear sections in either case, as shown. FIG. 3 illustrates how the ski plate  12  is actually integrated right into the ski, and is not removable. 
     FIG. 4 illustrates an alternative embodiment wherein two layers of panel linkages  16  are sandwiched together in mirror arrangement, such that upon compression the longitudinal movement of the top plate  8  and ski plate  12  are cancelled out by the opposite longitudinal motion of the middle plate  10 . The top plate  8  is coupled to the middle plate  10  via panel linkages  16  and their respective flexural couplings  26 , and the middle plate  10  is coupled to the ski plate  12  via panel linkages  16  which slant in the opposite direction. Therefore, in the embodiment illustrated in FIG. 4 top  8  and ski plates  12  would sheer to the right upon compression, and a middle plate  10  would sheer to the left an equivalent amount. This embodiment is a useful alternative in situations where longitudinal movement needs to be constrained. 
     The embodiment illustrated in FIG. 4 has a plurality of panel linkages  16  coupled to the top  8 , middle  10 , and ski plates  12  defining primary flexure axes  32  on the top plate  8 , secondary flexure axes  36  on the middle plate  10 , tertiary flexure axes  38  on the middle plate  10  and quaternary flexure axes  40  on the ski plate  12 . Thus compressive forces applied to the top  8  and ski  12  (third) plates  12  compressibly move the top  8 , middle  10  and ski  12  plates relative to each other while keeping the primary flexure axes  34  substantially parallel to the secondary flexure axes  36  and the secondary flexure axes  36  substantially parallel to the tertiary flexure axes  38  and the tertiary flexure axes  38  substantially parallel to the quaternary flexure axes  40  during compression. This drastically reduces impacts, while maintaining positive edge control and allowing for a net vertical movement while minimizing longitudinal sheer. 
     FIG. 5 illustrates another alternative embodiment of FIGS. 1-3, wherein formed rod linkages  14  take the place of panel linkages  16 . The formed rod linkages  14  define flexure axis  28   a  on the top plate  8  and  28   b  on the ski plate  12 . The plates move in relation to each other by pivoting on respective formed rod linkages  14 . The flexure axes of this embodiment are collectively referred to as flexure axis  28 . The top plate  8  and ski plate  12  have cylindrical holes  24  for receiving the formed rod linkages  14 . The formed rod linkages  14  pass substantially transversely through the top plate  8  and ski plate  12  through these cylindrical holes  24 , creating flexure axis  28  in a similar configuration to the first embodiment with panel linkages  16  pictured in FIG.  2 . Thus the flexure axis  28  on the top plate  8  and ski plate  12  remain substantially parallel to one another as the plates move about the formed rod linkages  14 . 
     The formed rod linkages  14  can be made out of any formed alloy rod or material of similar performance characteristics—even some molded plastics such as nylon would suffice. Preferably their diameter is 0.040-0.060 inches. Preferably the cylindrical holes  24  have an inner diameter of not more than 0.005 inches greater than the outer diameter of the formed rod linkages  14 . Thus lateral rotational movement is minimized, maximizing edge control of the ski. 
     It&#39;s important for the top plate  8  and the ski plate  12  to be fairly rigid laterally, thus they should be made from a relatively high-strength plastic such as fiber-reinforced Nylon (and/or alloy, depending on desired performance characteristics). All three plates  8 ,  10 , 12  may be channeled, honeycombed, hollow in parts, even consist of multiple pieces—anything that allows for lightweight and adequate lateral rigidity (see example of altered shapes in FIG.  6 ). Anything which acts as a firm attachment for the linkages  14  is suitable. The preferred thickness range is 0.070-0.100 inches, depending on the diameter of the formed rod linkages  14  used. 
     There are a variety of methods for holding the formed rod linkages  14  laterally in place within the top plate  8  and ski plate  12 . Preferably they would be insert molded into the top  8  and ski plates  12 , but in lieu of that c-clips can be used, or the formed rod linkages  14  may simply be crimped on the ends. 
     FIG. 6 illustrates an elaboration of the alternative embodiment pictured in FIG.  5 . As in FIG. 4, this version involves layering of linkages  14 , 16 , except in this case the linkages are formed rod linkages  14 . As in FIG. 3, FIG. 6 illustrates the elimination of linkages in the middle portion of this suspension system (between the binding toe  6   a  and the binding heel  6   b ). 
     Ideally all of the above embodiments of this suspension system are integrated into the ski in unitary construction (wherein the ski plate  12  is essentially the top portion of the ski and bonded accordingly). This is illustrated most clearly in FIG.  3 . This allows for reduced weight, greater lateral rigidity, and a lower profile. As a less ideal alternative, a variety of fasteners can be used to attach this suspension system to a ski via the ski plate  12 . These means include screws, gluing, various male-female type attachments, or rivets. If fasteners of any sort are used, there is very little need for any form of gasketing between the ski (as is imperative in U.S. Pat. No. 4,896,895 to Meyer) with the suspension system of this invention, as the ski plate  12  and top plate  8  are relatively flexible fore-aft, but torsionally rigid. In addition, the resilient elements  20  naturally sheer fore-aft when the ski is flexed. This relieves direct longitudinal pressure on the top plate  8 , which allows for better performance of the ski and more “feel” for the terrain, as it promotes the natural flexing of the ski and negates any possibility for the “flat spot” encountered with Meyer et al. 
     Bindings are fastened onto the suspension system of this invention in conventional ways—either by drilling through the top plate  8  and fastening screws accordingly, or alternatively, having screwserts embedded into the top plate  8  which allow for ready attachment of given binding configurations. Any method which allows for a secure attachment will suffice. 
     As an alternative (or in addition) to using the resilient elements  20  for damping, the formed rod linkages  14  may actually double as torsion bars. This could be achieved by offsetting the flexure axis  28  a little from each other (on the longitudinal plane) so that a twisting dynamic would take place upon compression of the top plate  8 , thus creating a dynamic which forces the top plate  8  and ski plates  12  apart—an effective spring. Damping of this spring action is still desirable through the use of resilient elements  20  such as elastomers, however. 
     Another way of providing for damping and spring action is to incorporate magnets, which by facing each other between the top plate  8  and ski plate  12 , exert a repelling force which drives said plates away from each other, thereby effecting a springing action. This can be in conjunction with, or in addition to the aforementioned means for providing rebound and damping. 
     Linkages  14 , 16  may have their angles reversed, such that they collapse the other direction upon compression. This is largely a matter of individual preferences, skier&#39;s ability, and other performance characteristics of the ski. 
     This specification sets forth the best mode for carrying out the invention as known at the time of filing the patent application and provides sufficient information to enable a person skilled in the art to make and use the invention. The specification further describes materials, shapes, configurations and arrangements of parts for making and using the invention. However, it is intended that the scope of the invention shall be limited only by the language of the claims and the law of the land as pertains to valid U.S. patents.
A suspension system for skiis which incorporates a plurality of linkage mechanisms that control absorption dynamics. The linkage mechanisms couple a plurality of plates between the ski binding and the ski. A plurality of resilient elements are located between these plates to dampen impact forces and resiliently maintain spacing between the ski bindings and the ski. The linkage mechanisms may include unitarily constructed panels having flexural couplings or formed rod linkages. These linkage mechanisms constrain the lateral rotational motion of the plates relative to the ski, thus providing edge control concurrent with vertical movement. This allows for precise edge control and significant absorption of impacts and vibration. This device may be integral with the ski, or mounted on top of the ski. In either case, it is a mounting platform for the bindings.