Abstract:
A wear bar assembly is disclosed for aiding in the steering of a snow machine. The assembly may include a wear bar for attachment to a bottom of a snow machine ski and one or more hardened inserts, each insert extending outward from the bottom of the wear bar. The one or more inserts extend outward from the bottom of the wear bar with a varying height. An apparatus for use as a snow machine ski is also disclosed. The apparatus may include a base, a tip formed integrally with the base and extending longitudinally forwardly from the base, a tail formed integrally with the base and extending longitudinally rearwardly from the base, at least one keel disposed to extend downwardly from the base, and the wear bar assembly with progressively varying inserts extending downwardly from the keel.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This application claims benefit of U.S. Provisional Patent Application No. 60/509,484 entitled WEAR BAR FOR SNOW MACHINE SKI and filed on Oct. 8, 2003 for Verlin M. Simmons et al. which is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to skis used on snowmobiles and similar vehicles and more particularly relates to wear bars attached to a bottom surface of the ski for turning on ice and snow. 
   2. Description of the Related Arts 
   Technology has made it possible to travel off-road during winter, even in very remote areas. Current machines for traveling over snow, such as snowmobiles, for example, provide the ability to travel swiftly and safely in back-country locations where the terrain is quite rugged. Winter sports industries such as recreational vehicle sales and rentals and tourism are growing rapidly as a consequence of this new technology. Industry and rescue operations are also benefiting greatly. 
   Snow machines continue to be refined and improved. For instance, in the case of snowmobiles, improved performance and reliability allows operators to travel swiftly, safely, and comfortably into secluded regions otherwise inaccessible in winter and in some cases in summer also. Other technological advances, such as increased traction, power, and weight reduction are allowing snowmobiles to be operated in snow depths and terrain previously thought impossible. 
   The snowmobile is a light and agile tracked snow machine that is intended primarily for recreational operation by one or two persons. The small size, lightness, and high power output of these machines makes them highly responsive to shifts in weight and other operator inputs. Using tracks with large lugs and high powered engines, these machines can go faster over trails and deeper in rugged terrain than larger snow machines such as the dual-tracked, multiple passenger vehicles currently available. The ruggedness of snowmobiles allows operators to travel over the snow safely at speeds impossible to match by wheeled vehicles in summer and to travel directly to any desired point by “as-the-crow-flies” navigation. 
   Typically, a snowmobile comprises an elongated rubberized looped track of about 10 or more feet in length, of which three to six feet contact the snow. The snowmobile is driven by a two-stroke or four-stroke engine, and the power is applied to the track with the use of a centrifugal clutch. Unlike dual-tracked snow machines, the snowmobile track does not extend entirely to the front of a snowmobile. Instead, the front of the machine rests on one or two specially adapted skis, such as the ski  100  of  FIG. 1 . The skis are attached to the steering mechanism of the snowmobile which may be provided with suspension components to handle bumps. With the use of the handle bars, the operator is able to alter the facing of the skis. Turning the skis in a selected direction generally causes the snowmobile to follow the selected direction of travel of the skis and turn in that direction. 
   Conventional snowmobile skis are designed under the notion that to provide the highest degree of speed and flotation, the ski must be smooth and relatively flat. Thus, conventional snowmobile skis are typically smooth and flat. A single shallow keel is often tyically provided extending along the center of the ski to exert a lateral shear force against the snow when the ski is turned, forcing the ski to adhere to an intended direction of travel. Alternatively, a ski with dual keels such as the ski  100  of  FIG. 1  has been developed to improve flotation, safety, and turning. 
   Wear bars  118  are typically placed at the bottom of the keels of the snowmobile skis, generally at the bottom of the keels as shown in  FIG. 1 , though not necessarily so. One or more wear bars  118  may be located on the bottom of each ski. The wear bars  118  enhance the turning ability of the ski  100 , especially on hard packed snow and ice. The wear bars are also typically replaceable, allowing a low cost part to be replaced periodically when wear occurs, rather than the entire ski. 
   Even with the use of keels and wear bars, conventional snow machine skis may still experience lateral slippage on hard packed surfaces. The sliding of the conventional skis in the original direction of travel is termed “pushing.” In order to overcome this behavior, hardened inserts have been coupled to the wear bars  118 . The inserts, generally positioned towards the rear of the wear bar  118 , provide additional shear force during a turn. In some wear bar designs, hardened inserts  202 , as seen with reference to  FIG. 2 , are generally configured extending outward from approximately the bottom of the wear bar  118  and are disposed at the rear of the wear bar  118 . Unfortunately, on hard-packed surfaces, this arrangement causes a situation wherein the wear bar  118  may not be in contact fully with a hard packed surface, as illustrated in  FIG. 2 . In such a situation, the ski tips to the front, causing the wear bar and consequently the hardened inserts  204  to contact the underlying surface (e.g., hardened snow or ice) at an angle. This can cause the snowmobile to track improperly on a hard-packed surface, and can cause the wear bar  118  to wear unevenly. 
   As technological barriers are being overcome, certain limitations of current snow machines have come glaringly to light. To fully utilize current technological benefits, snowmobiles must be provided with increased flotation ability, steering ability, and tracking capability. Until these needs are met, much terrain will remain impassible or at least dangerous to the operators of snow machines. 
   As a result of the above discussion, it should be readily apparent that if a ski could be used to provide high floatation in powder snow and also provide improved steering on packed and groomed surfaces, the ski would be a great improvement in the art, complementing the technological advances already made. Such a ski would provide increased winter access to rugged terrain, greater enjoyment to consumers, and greater safety for those traveling off-road in winter. 
   SUMMARY OF THE INVENTION 
   The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available wear bar assemblies. Accordingly, the present invention has been developed to provide a wear bar assembly that overcomes many or all of the above-discussed shortcomings in the art. 
   The wear bar assembly may comprise a wear bar for attachment to a bottom of a snow machine ski, one or more hardened inserts, each insert extending outward from the bottom of the wear bar, and wherein the one or more inserts extend outward from the bottom of the wear bar with a varying height. In one embodiment, each insert extends outward at an angled height having an angle in the range of between about 2 and 20 degrees. Alternatively, the angle may be in the range of between about 5 and 12 degrees. 
   The angled height may be formed by a first end extending outward approximately 1/64 inch and laterally increasing to a second end extending outward approximately 1 inch. In a different embodiment, the angled height is formed by a first end extending outward approximately 1/32 inch and laterally increasing to a second end extending outward approximately ½ inch. 
   In one embodiment, the inserts may extend outward with a stepped height having increasing heights in the range of between about 1/64 inch and 1 inch. In a further embodiment, the inserts extend outward with increasing heights in the range of between about 1/32 inch and ½ inch. The hardened inserts may be formed of a carbon metal compound. In another embodiment, a combined length of the inserts is substantially equivalent to a length of the wear bar. Alternatively, the combined length of the inserts is less than the length of the wear bar. In another embodiment, each insert has a length in the range of between about ¼ and 12 inches. 
   An apparatus of the present invention is also presented. In particular, the apparatus, in one embodiment, includes a base comprising a gliding surface for moving over snow, the gliding surface extending in a longitudinal direction positionable to correspond to a desired direction of travel, and extending in a lateral direction between a first edge and a second edge. The apparatus also includes a tip formed integrally with the base and extending longitudinally forwardly from the base, and a tail formed integrally with the base and extending longitudinally rearwardly from the base. 
   In a further embodiment, the apparatus may include a pair of keels disposed to extend downwardly from the base proximate the first and second edges, respectively, to form a channel extending a distance selected to be effective to apply a turning force in the lateral direction effective to maneuver a snow machine over snow and ice covered terrain. The keels may have a plurality of wear bars, each wear bar configured to extend downwardly from one keel. 
   Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. 
   Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. 
   These features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: 
       FIG. 1  is a perspective view diagram illustrating one embodiment of a snow machine ski in accordance with the prior art; 
       FIG. 2  is a schematic block diagram illustrating one embodiment of a wear bar in accordance with the prior art; 
       FIG. 3  is a schematic block diagram illustrating one embodiment of a wear bar in accordance with the present invention; 
       FIG. 4  is a schematic block diagram illustrating an alternative embodiment of a wear bar in accordance with the present invention; 
       FIG. 5  is a schematic block diagram illustrating another embodiment of a wear bar in accordance with the present invention; 
       FIG. 6  is a schematic block diagram illustrating one embodiment of a wear bar insert in accordance with the present invention; 
       FIG. 7  is a schematic block diagram illustrating an alternative embodiment of a wear bar insert in accordance with the present invention; 
       FIG. 8  is a schematic block diagram illustrating another embodiment of a wear bar insert in accordance with the present invention; 
       FIG. 9  is a schematic block diagram illustrating another alternative embodiment of a wear bar insert in accordance with the present invention; 
       FIG. 10  is a schematic block diagram illustrating an embodiment of a wear bar in accordance with the present invention; 
       FIG. 11  is a schematic block diagram illustrating one embodiment of a wear bar having a plurality of inserts in accordance with the present invention; 
       FIG. 12  is a schematic block diagram illustrating a wear bar having an opening for receiving at least one insert in accordance with the present invention; 
       FIG. 13  is a schematic block diagram illustrating an alternative embodiment of a wear bar having an opening for receiving at least one insert in accordance with the present invention; and 
       FIG. 14  is a schematic block diagram illustrating another embodiment of a wear bar having an opening for receiving at least one insert in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. 
   Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
   Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     FIG. 1  is a perspective view diagram illustrating one embodiment of a snow machine ski  100  in accordance with the prior art. The snow machine ski (hereinafter “ski”)  100  maybe functionally divided into an upturned tip  102 , a tail  104 , and an intervening base portion  106 . The base portion  106  extends in a longitudinal direction extending from the tip  102  to the tail  104 . 
   In one embodiment, the ski  100  may include a bracket  107  for connecting to a steering mechanism of a snow machine (not shown). In the depicted embodiment, the bracket  107  is provided for connecting to a steering spindle of a snowmobile. The ski  100  may also include a loop  108  configured to act as a bumper for protecting the front of the ski from impacts, while also providing a gripping handle for the operator. The loop  108  may be dynamically mounted at one or both ends, providing flexibility and shock absorption to the tip  102 . 
   In a further embodiment, the loop  108  is fixedly coupled to the tip  102  of the ski  100  with bolts  110 . The loop  108  bends up and back, transitioning through a first apertured sliding brace  112 , and through a second apertured sliding  114 . A free end of the loop  108  (not shown) is movable in a longitudinal direction with respect to the braces  112 ,  114  allowing the loop  108  to flex within the braces  112 ,  114 . This arrangement allows the tip  102  to flex backwards and absorb shock normally transmitted through conventional snow machine skis. 
   In one embodiment, the ski  100  may comprise one or more downwardly extending keels  116 . The keels  116  may extend over the length the ski  100 , or alternatively, extend longitudinally along the bottom of the base portion  106 . In a further embodiment, the keels  20  may not be present on the tip  102  or the tail  104 . Shown attached to each keel  116  is a wear bar  118 . 
   The wear bar  118  may comprise an elongated metal wear bar designed to make primary contact with harder surfaces, such as roadways and packed or icy snow, in order to prevent wear. The wear bar  118  is also designed to focus the weight of the snow machine on a smaller surface area, acting as runners and guides for improved steering control. As depicted in  FIG. 1 , the ski  100  comprises one or more wear bars  118 . Of course the ski  100  may also be implemented with a centrally located wear bar  118 , or with three or more wear bars  118 . 
     FIG. 2  is a schematic block diagram graphically illustrating one embodiment of the wear bar  118  in accordance with the prior art. The wear bar  118  may comprise one or more hardened inserts  202  (hereinafter “inserts”). The inserts are preferably formed of a hardened material such as carbon metallic compound. For example, the inserts of the present invention may be formed of a compound of carbon with one or more metallic elements, as is currently found on conventional wear bars. The metallic elements may include, but are not limited to, tungsten, tantalum, titanium, and chromium. 
   The inserts  202  are generally configured extending outward from approximately the bottom of the wear bar  118  and are disposed at the rear of the wear bar  118 . Unfortunately, on hard-packed surfaces, this arrangement causes a situation wherein the wear bar  118  may not be in contact fully with a hard packed surface, as illustrated in  FIG. 2   a . In such a situation, the ski tips to the front, causing the wear bar and consequently the hardened inserts  204  to contact the underlying surface (e.g., hardened snow or ice) at an angle, leaving a gap  204  where the wear bar should contact the surface of the snow or ice. This gap  204  may contribute to improper snowmobile tracking on a hard-packed surface, and additionally may cause the wear bar  118  to wear unevenly. 
     FIG. 3  is a schematic block diagram graphically illustrating one embodiment of a wear bar  300  in accordance with the present invention. In one embodiment, a plurality of inserts  302  are positioned toward an end  304 ,  306  of the wear bar  300 , though the inserts  302  may be positioned at other locations on the wear bar  300 . In order to overcome the problem discussed above with reference to  FIG. 2 , each insert  302  may be configured to extend outward from the wear bar  300  with a varying height. Each insert  302  may be individually positioned within the wear bar  300 , or alternatively positioned such that the inserts  302  collectively form a continuous insert  302  surface. 
   For example, insert  302   a  which is positioned closest to a first end  304  of the wear bar  300 , extends outward with a height in the range of between about 0 inch (flush with the bottom of the wear bar  300 ) and about ⅛ th  inch. Subsequent inserts  302   b ,  302   c ,  302   d  may gradually increase in height such that the wear bar maintains full contact with a surface. In one embodiment, the maximum height of any insert is in the range of between about ¼ inch and 1 inch. In an alternative embodiment, the maximum height is approximately ½ inch. 
     FIG. 4  is a schematic block diagram graphically illustrating an alternative embodiment of a wear bar  400  in accordance with the present invention. In one embodiment, the wear bar  400  may comprise a single insert  402 . The insert  402  may have any length less than the overall length of the wear bar  400 . In a further embodiment, the insert  402  has a length in the range of between about 2 and 12 inches. Alternatively, the length of the insert  402  may be in the range of between about 4 and 7 inches. 
   The insert  402  extends outward from the wear bar  400  with a gradually varying, progressively increasing height. As discussed above with reference to  FIG. 3 , the insert  402  may extend outward at a first end  404  with a height in the range of between about 0 inch (flush with the bottom of the wear bar  400 ) and about ⅛ th  inch. Alternatively, the insert  402  may extend outward as depicted, with an angled first end  404 , and subsequently increasing height towards a second end  406 . The height of the insert  402  at the second end  406  may be in the range of between about ¼ inch and 1 inch. 
     FIG. 5  is a schematic block diagram graphically illustrating an alternative embodiment of a wear bar  500  in accordance with the present invention. The wear bar  500  may comprise a plurality of inserts  502 , each insert  502  similar in size and shape to inserts  302  of  FIG. 3 . In the depicted embodiment, the inserts  502  may be equally spaced across a bottom surface of the wear bar  500 . The inserts  502  are configured with stepped, progressively increasing heights, the shortest height being placed closest to a first end  504 , and gradually increasing the greatest height positioned closest to a second end  506 . 
     FIGS. 6–9  are schematic block diagrams graphically illustrating different embodiments of inserts in accordance with the present invention.  FIG. 6  illustrates an embodiment of a stepped height insert  600 . The insert  600  is a collection of smaller inserts  602 . Alternatively, the insert  600  may be formed as a single insert  700 , as depicted with reference to  FIG. 7 . 
     FIG. 8  illustrates an insert  800  having a stepped profile similar to the insert  600  of  FIG. 6 . However, the insert  800  may include angled portions  802  configured to reduce drag as the insert cuts through snow and ice covered terrain, or travels over hard surfaces such as a concrete or pavement. Likewise, the insert  800  may be formed as a single insert instead of a collection of smaller inserts  804 . 
     FIG. 9  illustrates an alternative embodiment of an insert  900  in accordance with the present invention. The insert  900  may be formed of smaller inserts  902  configured with a continuously sloping cutting surface in place of a stepped height surface. As with  FIGS. 6 and 8 , the insert  900  may also be formed as a single insert. 
     FIG. 10  is a schematic block diagram illustrating one embodiment of wear bar  1000  in accordance with the present invention. The wear bar  1000  may be configured with a plurality of openings  1002 , each opening having a different depth. The depth of each opening  1002  is graphically represented by dashed lines. The openings  1002  are each configured to receive a hardened insert. The varying depth of the openings  1002  allow a common insert to be used to achieve varying height inserts and overcome the problem of having the gap  204  as discussed with reference to  FIG. 2 . 
     FIG. 11  is a schematic block diagram illustrating the wear bar  1000  having a one insert in each opening  1002  in accordance with the present invention. As discussed above with reference to  FIG. 10 , a plurality of inserts  1102 , each having the same height, may be placed into the openings  1002 . Due to the varying depths of the openings  1002 , however, the inserts  1102  will subsequently have exposed portions  1104  with varying heights extending outward from the wear bar  1000 . 
     FIG. 12  is a schematic block diagram illustrating a wear bar  1200  having a single opening  1202  in accordance with the present invention. The single opening  1202  may be angled such that a single insert having a uniform height will result in an exposed portion that extends outward from the wear bar with a varying height. The opening  1202  may extend along substantially the entire length of the wear bar  1200 . Alternatively, the opening  1202  may be considerably shorter, and may be positioned in the middle, or closer to one end of the wear bar, as in  FIG. 13 . 
     FIG. 14  is a schematic block diagram illustrating one embodiment of a wear bar  1400  having a plurality of openings  1402  in accordance with the present invention. The openings  1402  may be formed in the wear bar  1400  having an angled (not parallel to a bottom surface  1406  of the wear bar  1400 ) base  1404 . Each opening  1402  is configured to receive a standard insert, and angle the insert to have a stepped height that is not parallel to the bottom surface  1406  of the wear bar  1400 . 
   The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.