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CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of U.S. Provisional application Ser. No. 60/119,163, filed Feb. 8, 1999. 
    
    
     FIELD OF THE INVENTION 
     The present invention pertains to snow rakes. In particular, the present invention pertains to a snow rake including a low friction of lubricious sheath. 
     BACKGROUND OF THE INVENTION 
     Ice dams occur when water from melting snow freezes near the edge of a roof, such as a gutter line, and traps other melt water behind it. This water can run back up under the shingles and rot the wood sheathing and leak into the house. Snow melt can be caused by ambient weather conditions or from heat escaping from the house. One way of preventing ice damming is removing snow from the roof before the snow melts. To avoid the risks associated with climbing onto the roof, snow rakes have been developed which can be manipulated by a user on the ground. 
     Conventional snow rakes include an elongate handle and a blade disposed at the distal end of the handle. A user standing on the ground can lift the handle such that the blade is disposed several feet above the edge of a pitched roof. The blade is disposed transversely to the pitch or fall line of the roof. Then, the handle is pulled proximally toward the user. This drags the blade down the roof. As the blade is dragged down the roof, snow is scraped from the roof and falls downward. Depending upon the depth of the snow, several passes will be necessary to skim off successive layers of snow. After successive layers of snow have been skimmed off from a particular portion of the roof, until the roof is exposed, then the user can move the rake to another portion of the roof. 
     As several layers of snow must generally be skimmed off before an area of a roof is cleared or exposed, clearing a roof with a conventional snow rake can be a time consuming chore. It would thus be desirable to have a tool which can more efficiently be used to clear snow from a roof. 
     SUMMARY OF THE INVENTION 
     The present invention pertains to a snow rake for removing snow from a roof. The snow rake includes an elongate handle and a blade disposed at the distal end thereof. The blade extends transversely to the handle. An opening extends through the blade. A bottom portion of the blade is preferably sharpened to create a frost edge. Extending distally from the blade is a partially coiled, low friction lubricious sheath. 
     A user standing on the ground raises the blade several feet above the edge of a pitched roof. The blade is then drawn downward, slicing through the snow, until it reaches the surface of the roof. As the blade is drawn through the snow, most of the snow passes through the opening, remaining in place on the roof. The lubricious sheath, however, is uncoiled beneath snow as the blade is dragged downward. Once the sheath is disposed between the roof surface and the snow, the relatively high frictional interface between the snow and the roof is replaced by a low friction interface between the snow and the sheath. The snow then readily slides downward off the roof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects in the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the Figures thereon and wherein: 
     FIG. 1 is a side view of a snow rake in accordance with the present invention; 
     FIG. 2 is a top view of a snow rake in accordance with the present invention; 
     FIG. 3 is a front view of the blade of the snow rake in accordance with the present invention; and 
     FIG. 4 is an end view of a gabled roof and the snow rake of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. In some cases, the drawings may be highly diagrammatic in nature. Examples of constructions, materials, dimensions, and manufacturing processes are provided for various elements. Those skilled in the art will recognize that many of the examples provided have suitable alternatives which may be utilized. 
     Referring now to the drawings, FIG. 1 is a side view of a snow rake  10  in accordance with the present invention. Snow rake  10  includes an elongate handle  12 . Disposed near one end of handle  12  is a blade  14 . Extending from blade  14  is a partially coiled lubricious sheet  16 . 
     Handle  12  has a distal end  18 . Handle  12  is preferably 10 to 20 feet long, or longer as is necessary to reach the roof of a structure. Handle  12  may be made from a single, elongate rod, a telescoping rod, or a rod which comes in several segments which can be connected together to create a handle  12  of sufficient length. 
     Blade  14  preferably includes a tubular coupling  20  through which handle  12  can extend. A screw, pin or other fastener  22  can extend through handle  12  and coupling  20  into a top portion  24  of blade  14 . Blade  14  also includes a bottom portion  26 . It can be appreciated, by reference to subsequent figures that blade  14  has a rectangular configuration extending transversely to handle  12 . Top portion  24  and bottom portion  26  define the top and bottom of an opening extending through blade  14 . Bottom portion  26  includes a proximal edge  28 , which preferably is sharpened to create a frost-edge sufficiently sharp to slice through densely packed snow. A leading portion  33  of sheet  16  can be disposed in a recessed slot in bottom portion  26  and fastened thereto by screw or other fastener  32 . Blade  14  is preferably made from a light metal, such as aluminum or plastic. 
     Sheet  16  is preferably biased into a partially coiled configuration including at least one curved portion  34  disposed between a leading edge  30  and a distal edge  36  of sheet  16 . Sheet  16  is preferably formed such that it is internally biased to recoil if straightened. Lubricious sheet  16  preferably comprises a material which is durable, light weight, and provides a surface having a relatively low coefficient of friction. Examples of materials which may be suitable in some applications include: polyolefin, polyvinylchloride (PVC), polyurethane, polytetrafluoroethylene (PTFE), polyamide, and polyimide. Examples of polyolefins which may be suitable in some applications include polyethylene (PE) and polypropylene (PP). In a preferred embodiment, sheet  16  has a thickness between about 0.020 inches and 0.080 inches. 
     In FIG. 1, sheet  16  of snow rake  10  is disposed in a first position A. Sheet  16  may also assume a second substantially uncoiled position B. For example, blade  14  may be drawn downward, slicing through a layer of snow disposed on a roof. As blade  14  is drawn through the snow, sheet  16  will be uncoiled beneath a substantial portion of the snow as blade  14  is dragged downward. Once sheet  16  is disposed between the roof surface and the snow, the relatively high frictional interface between the snow and the roof is replaced by a low friction interface between the snow and sheet  16 . The snow then readily slides downward off the roof. In a preferred embodiment, sheet  16  is biased to assume position A when there are no outside forces (e.g., the weight of the snow) acting on it. 
     In FIG. 1, it may be appreciated that sheet  16  includes curved portion  34  when sheet  16  disposed is in first position A. Sheet  16  defines a gliding surface  35 . When snow rake  10  is being utilized to clear snow from a roof, gliding surface  35  may be utilized to assist in positioning snow rake  10 . For example, the distal end of snow rake  10  may be lifted to a location proximate the lowest portion of the roof. Snow rake  10  may then be lowered until gliding surface  35  of sheet  16  contacts the roof or a layer of snow overlaying the roof. It may be appreciated that resting gliding surface  35  on the roof will significantly reduce the force required from the person using the roof rake. The distal end of snow rake  10  may be advanced to a higher location of the roof by pushing distally on handle  12  and allowing gliding surface  35  to slide along the roof or a layer of snow overlaying the roof. 
     In FIG. 1 it may be appreciated that gliding surface  35  includes a curved surface portion  36  and a substantially flat surface portion  37 . Curved surface portion  36  is defined by curved portion  34  of sheet  16 . Substantially flat surface portion  37  is defined by an intermediate portion  38  of sheet  16 . Intermediate portion  38  of sheet  16  is disposed between leading edge  30  and trailing edge  36  of sheet  16 . Embodiments of the present invention have been envisioned in which intermediate portion  38  of sheet  16  includes one or more ribs. 
     In the embodiment of FIG. 1 leading portion  33  of sheet  16  is rotationally fixed relative to blade  14 . Also in the embodiment of FIG. 1, substantially flat surface portion  37  of gliding surface  35  is disposed such that it is substantially parallel to handle  12 . As described above, gliding surface  35  on the roof or on a layer of snow overlaying the roof. The distal end of snow rake  10  may be advanced to a higher location of the roof by pushing distally on handle  12  and allowing gliding surface  35  to slide along the roof or a layer of snow overlaying the roof. In the embodiment of FIG. 1, a pushing force applied along the longitudinal axis of handle  12  will have a direction which is substantially parallel to gliding surface  35 . Other embodiments are possible without deviating from the spirit and scope of the present invention. For example, handle  12  could be pivotally connected to blade  14  and include a fastener allowing the angle between blade  14  and handle  12  to be fixed at an angle desired by the user of snow rake  10 . 
     FIG. 2 is a top view of snow rake  10  with sheet  16  disposed in substantially uncoiled position B. In FIG. 2 it can be seen that blade  14  extends transversely to handle  12 . A plurality of fasteners  32  arc shown connecting leading portion  33  of sheet  16  to bottom portion  26  of blade  14 . Side portions  25  and  27  of blade  14  are also shown. Distal edge  36  of sheet  16  defines a handle cut  38 . In a preferred embodiment, handle cut  38  is adapted to be disposed about handle  12  when sheet  16  is in first position A. Sheet  16  preferably has a transverse dimension  39  approximately equal to the transverse dimension of the opening through blade  14  between side portions  25  and  27 . 
     FIG. 3 is a front view of blade  14  showing top portion  24 , bottom portion  26  and side portions  25  and  27  defining an opening therebetween. Tubular coupling  20  is disposed on, and preferably welded to, top portion  24  and screw  22  extends through coupling  20  and into tip portion  24 . Blade  14 , as shown, has a generally rectangular configuration and opening. It can be appreciated, however, that blade  14  could have alternate shapes, such as a triangular shape. 
     FIG. 4 is a side view of snow rake  10  and a gable end of a roof  50 . Roof  50  has a roof surface  52  which can have a soffit  54  extending from a wall  56 . A layer of snow  58  is disposed on roof surface  52 . Snow rake  10  has been advanced onto roof surface  52  sufficiently high to have placed blade  14  at approximately the current location of curved portion  34  of sheet  16 . In the position shown in FIG. 4, blade  14  has been drawn downwardly in the direction of the arrow adjacent to handle  12  Such that a portion of sheet  16  is now disposed beneath snow  58 . Snow rake  10  is preferably pulled further in the direction of the arrow until blade  14  is pulled to the edge of roof surface  52 . While blade  14  is drawn downward along roof Surface  52 , sheet  16  is sufficiently flexible to uncoil under snow  58 . When sheet  16  is uncoiled, it will extend from approximately as high on the roof as curved portion  34  is shown in FIG. 4 to the edge of roof surface  52 . When lubricious sheet  16  is disposed under snow  58  in this manner, the friction holding snow  58  to roof surface  52  will be reduced substantially by the interpositioning of sheet  16 . The snow on sheet  16  will then readily slide downwardly from roof surface  52 . A sufficient amount of snow should be removed from the roof to reduce or eliminate the potential of ice damming as can be appreciated by those skilled in the art. 
     It can be appreciated that sheet  16 , when partially coiled resembles a toboggan, and thus can act as a toboggan to carry blade  14  over snow  58  of FIG.  4 . It can also be appreciated that coupling  20  could be configured to allow the angle of handle  12  to be varied relative to blade  14 . For example, coupling  20  could be pivotally connected to blade  14  and include a fastener allowing the angle between blade  14  and handle  12  to be fixed at a desired angle. Handle  12  could also be reversed such that snow could be pushed from the roof when a person was standing above blade  14  on the roof rather than below as shown in FIG.  4 . 
     Numerous characteristics and advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size and ordering of steps without exceeding the scope of the invention. The invention&#39;s scope is, of course, defined in the language in which the appended claims are expressed.

Summary:
Devices and methods for removing snow are disclosed. A snow removal device in accordance with the present invention includes an elongate handle having a distal end and a proximal end, and a flexible sheet having a leading edge and a leading portion proximate the leading edge. The leading portion of the flexible sheet is fixed to the elongate handle proximate the distal end thereof. The flexible sheet has a first position defining a gliding surface, and a second position wherein the flexible sheet is substantially flat. The flexible sheet is, preferably, biased to assume the first position.