Abstract:
A device for sharpening ski edges and the like which is useful in sharpening both the side and bottom edges of skis is disclosed. The device is operable easily by an individual, is portable and allows a bevel to be sharpened into the edge where desired quickly and easily.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a device for sharpening snow ski edges and more specifically to a motorized device for sharpening both the bottom and side edges of a snow ski or snowboard. 
     2. Description of the Prior Art 
     Down hill snow skis, including their cousin the snowboard, are made from a wide variety of materials including wood, fiberglass, plastic, resins and the like. Today&#39;s ski bases are usually made from a hard resin plastic such as p-tex. All these skis have metal edges which run the length of both lower edges of the ski that are designed to aid in griping the snow and aid in turning. In order for the ski edge&#39;s top performance characteristics to be maintained, both the side and bottom of the metal edge must be sharpened. Beveling of the metal edges is also done while sharpening. By beveling the edges, changes in the drag and turning characteristics can be greatly affected. The base bevel on modem skis can run from about zero to two degrees while the bevel on the side edge can run from about zero to five degrees. 
     Ski shops have typically been considered the best place to take skis for sharpening the ski edges. These shops can afford large motorized sharpening machines that hold the skis firmly in place and quickly and accurately sharpen the whole ski. But the time and cost of taking ones skis to a ski shop keeps most people from doing such sharpening as often as it should be done for optimum performance. 
     Accordingly, a wide variety of devices have been developed for sharpening ski edges away from the ski shop. They basically fall into two categories, manual sharpeners and motorized sharpeners. 
     Manual sharpeners tend to be a file with a file holder to maintain file alignment. There are serious problems however with the manual devices of the art. Specifically, these units are hard to keep aligned, removal of metal is uneven and because of the size of the file teeth, the file needs in general, to straddle both sides of the skis leading to problems with the p-tex base and interfering with even filing of the bottom edge. Because these manual sharpeners are extremely hard to use, people tend to discontinue their use rather rapidly. Another problem with manual sharpeners is the inability to adjust the angle on the file leaving the user with right angles (a zero degree bevel) as the only choice or at the very least the single choice of angles. 
     The majority of motorized sharpeners are the large floor or bench type models designed primarily for ski shop use. While there is at least one small hand held unit disclosed in the art, it suffers from difficulties in keeping the sanding disc at a proper angle since the motor, motor shaft and sanding disc are held parallel to the ski edge during use. The weight of the motor that is not supported in this configuration makes balance of the system impossible (French Patent 2,516,004). A further problem with this design is the tendency for the sanding disc to “run-away” from the user if not held tightly. 
     Another problem with previous motorized, hand held ski sharpeners is the lack of teaching of how one would sharpen the side edges of the skis since only bottom edge sharpening are taught. 
     Accordingly, it is an object of the present invention to provide a novel hand held motorized ski sharpening device that overcomes the problems discussed above. 
     It is also an object of the invention to provide a ski edge sharpening device that is capable of sharpening skis at a desired bevel angle. 
     It is yet another object to provide a ski sharpening device that is capable of sharpening both the side and bottom edges of a ski. 
     It is a further object to provide a sharpening device for skis that is balanced to use, does not require frequent changes of abrasives, and does not encourage the abrasive to “run-away” during use. 
     SUMMARY OF THE INVENTION 
     The present invention relates to hand held motorized devices designed to grind and sharpen the side and bottom edges of snow skis, including snowboards, at a desired bevel angle. 
     The device of the present invention uses a solid columnar grinding stone having a flat bottom portion to grind the bottom ski edge and a circumferential edge of the grinding stone to grind the side edge of the ski as the grinding wheel is moved along the length of the ski. The flat bottom portion can be angled as desired to give the desired bevel to the bottom edge. This grinding stone is driven by a hand held high-speed motor comprising a counter clockwise rotary driven shaft and wherein the grinding stone is spring-loaded for mounting in the drive shaft collet. 
     The motor is mounted to an edge guide holding the grinding stone against either the bottom edge or side edge as desired and consists of a base to lay flat on the ski, a runner portion to guide the base along the ski edge and a grinding stone aperture for allowing room for the grinding stone to be positioned against the bottom or side ski edge. 
     In one embodiment, the motor is mounted at an angle such that the desired bevel angle is shaped into the ski bottom edge while using a flat bottom grinding stone. 
     The edge guide is moved along the length of the ski with the grinding stone either against the bottom or side edge of the ski until the desired beveling and sharpening is obtained. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the sharpening edge guide of the present invention. 
     FIG. 2 is a front elevation view of the sharpening edge guide. 
     FIG. 3 is a perspective view of the motor and grinding wheel mounted on the edge guide. 
     FIG. 4 is a pictorial view showing the columnar grinding wheel and collet spring mounted in the motor collet via a mounting axle. 
     FIG. 5 is a side view of the device of the invention mounted on a ski for sharpening the bottom edge. 
     FIG. 6 is a side view of an embodiment of the edge guide that allows for adjustable bevel edges. 
     FIG. 7 is a side view of the device of the invention mounted on a ski for sharpening the bottom edge. 
     FIG. 8 is a perspective view of the device of the invention mounted on a ski for sharpening the bottom edge. 
     FIG. 9 is a perspective view of the device of the invention mounted on a ski for sharpening the side edge. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Now referring to the drawings in greater detail, a motorized ski sharpening device is presented for sharpening the bottom and side edges of a ski or the like. FIG. 1 is a perspective view of an edge guide  20  utilized by the sharpening device of the invention having a flat portion  22 . Its width  24  is designed to be at least about half the width of a ski or at least wide enough to form a stable platform against a ski base when in position. In one embodiment, width  24  of flat portion  22  is about two to three inches. The length  25  is sufficient to stably run the length of the ski and provides aperture  27  for accommodating the grinding stone  41  (shown in FIG.  3 ). Also, runner portion  29  is formed at about ninety degrees to flat portion  22  and runs along the length of a ski edge to be sharpened. 
     Motor mount  31  is designed as a means to hold a motor at a desired position or at a desired angle for beveling. In this embodiment, motor mounting holes  32  are designed to receive a pair of mounting bolts from a hand held motor  34 . 
     FIG. 2 is a front elevation view of edge guide  20  showing flat portion  22  and motor mounting plate  31 . In this view, the runner portion  29  on both sides of grinding stone aperture  27  is clearly seen. Motor mounting holes  32  are also clearly seen. 
     FIG. 3 is again a perspective view of edge guide  20 . This time motor  34  is shown mounted to motor mounting plate  31  via bolts  36  (only one of which is seen) into motor mounting holes  32 . Shown on motor  34  is variable speed switch  38  for adjusting the speed of spindle  40  to a desired speed. In one embodiment, motor  34  can drive the spindle apparatus from zero to about 25,000 to 35,000 RPM however more or less rotation is acceptable, as desired. At the end of spindle  40  is the solid columnar grinding stone  41 . In one embodiment, stone  41  is an aluminum oxide grinding stone. Other embodiments are contemplated but in all cases must be a solid grinding material, either artificial or natural, for grinding as opposed to, for example, a grinding stone sandpaper on a mounting wheel that has grinding material on the surface of the circumference only such as in French Patent 2,516,064. 
     FIG. 4 is a pictorial view of the solid columnar grinding stone  41 . From this perspective, spindle  40  can be seen mounted in collet  44 . Collet  44  is internally threaded to tighten around spindle  40 . In one embodiment, spindle  40  is threaded opposite to the direction of spin of motor  34 . For example, where motor  34  rotates spindle  40  in a counter clockwise direction as viewed from the end of collet  44 , collet  44  would have a right hand thread. The advantage of this arrangement will be explained later. Also shown in this view is compression spring  45  is mounted on spindle  40 . Spring  45  allows a height adjustment of solid columnar grinding stone  41  when spindle  40  is not completely tightened in collet  44 . After proper desired height is reached, collet  44  can be tightened in any manner desired. In this embodiment, the surface of grinding stone bottom  47  is flat and is used in the device of the invention to shape and grind the bottom edge of a ski. In this embodiment, the surface is flat but in other embodiments where a bevel is needed on the bottom edge, other shapes are contemplated for the bottom  47 . Also seen is the circumferential edge  48  of columnar grinding stone  41 . The circumferential edge  48  is used to grind and sharpen a ski side edge when edge guide  20  is properly placed on a ski. 
     FIG. 5 is a side view showing a cross section of the edge guide  20  with the motor  34  and grinding stone  41  attached. The device is resting in this view on a ski bottom edge  53  shown also in cross section. Ski  51  has a bottom edge  53  and side edge  54  as depicted. Motor mounting plate  31  is shown as an upright with flat portion  22  shown horizontally resting on ski  51 . Angle “a” is shown in this embodiment as ninety degrees. When spindle  40  is mounted parallel to motor mounting plate  31  and bottom surface  47  perpendicular to the spindle  40  grinding stone  41  will put a zero degree bevel on the bottom edge  53  of ski  51 . Adjusting of angle “a” will create a different bevel angle on bottom edge  53  as desired. Normally this is between about zero degrees and five degrees bevel angle. 
     FIG. 6 depicts a view of an alternate embodiment of the mounting plate  31  arrangement. In the previous FIG. 5, the motor mounting angle of the mounting plate  31  is fixed at angle “a” meaning that the bevel angle is predetermined and fixed. While the angle “a” can be made to different angles, once made, the angle “a” of the edge guide  20  will not change. In the embodiment depicted in FIG. 6, angle wedge  56  is placed between motor  34  and motor mounting plate  31 . Wedge  56  can be fixed but in one embodiment can be removable and interchanged with wedges of different angles thus allowing for changing of the final bevel angle on the bottom edge  53  of a ski. 
     FIG. 7 is a side view of another embodiment of the invention for adjusting the bevel angle of ski bottom edge  53 . In this view, the grinding stone bottom  47  has a bevel angle “b”. This angle is imparted to the ski edge  53  as a bevel when the grinding stone  41  is mounted as previously described in FIG.  5 . 
     FIG. 8 is a perspective view of the device of the invention in use on a ski, sharpening the bottom edge  53  of a ski  51 . In use, motor  34  is mounted to edge guide  20 . Spindle  40  of grinding stone  41  is placed loosely in collet  44 . Edge guide  20  is then placed on a ski bottom aligned with the runner portion tight against side edge with the bottom of grinding stone  41  flat against bottom edge  53 . The user then pushes grinding stone spindle up further into collet  44 . Motor  34  is started at about 25,000 to 35,000 RPM and edge guide  20  is moved up back and forth on the edge of ski  51 . In one embodiment, this loose spindle will be tightened at the proper height due to the counter clockwise rotating of motor collet  44  and the right hand tightening nut of collet  44 . The device is run back and forth on the ski edge until the desired level of sharpness or bevel is achieved. 
     FIG. 9 is a perspective view of the device of the invention in use on a ski, sharpening a side edge  54  of ski  51 . In order to use the device, motor  34  is mounted on edge guide  20  as above. Spindle  40  is tightened in collet  44  at a height such that grinding stone circumferential edge  48  rests against ski  51  side edge  54  when edge guide  20  is positioned as shown. The flat portion  22  is again against the ski bottom. In this embodiment, the circumferential edge  48  is against ski side edge  54 , which means that runner portion  29  does not fit flat against the ski side edge  54 . Instead, runner edge corner  59  and circumferential edge  48  is held against ski side edge  54  and moved back and forth on the ski side edge  54  until the desired level of sharpness is achieved. 
     It is clear that substitution of grinding stones, spindles, motors, desired angles and the like are well within the skill in the art in view of the disclosure herein. Nothing in the embodiments or drawings herein is designed to be limiting.