Abstract:
Extricating apparatus and methods are disclosed for aiding movement of a snowmobile after becoming bogged in deep and/or soft snow. The apparatus includes at least a first unit having a stretchable cord with first and second implements joined thereto at opposite ends of the cord. A flexible jacket is provided around but unconnected to the stretchable cord and intermediate the first and second implements, the jacket being made of material that is relatively more rigid than the stretchable cord. The implements are preferably either first and second couplers or a coupler and a graspable member such as a handle, first and second units, one each thus equipped, being preferred.

Description:
FIELD OF THE INVENTION 
     This invention relates to devices and methods adapted for freeing vehicles bogged in deep, loose snow, and, more particularly, relates to apparatus and methods for aiding extrication of an entrenched snowmobile. 
     BACKGROUND OF THE INVENTION 
     The recreational use of snowmobiles has increased significantly in recent years. The development of this recreation has led to the use of ever more powerful and heavy machines (many typically weighing 600 lbs. or more). Any snowmobile can become mired in deep or soft snow when the vehicle&#39;s drive track loses traction and the snowmobile settles in the snow. The advent of larger vehicles and the capability of travel further afield (where ungroomed or previously untracked terrain is often encountered) has made such entrenchment of snowmobiles an even more difficult problem for riders to resolve. 
     When so entrenched, the snowmobile&#39;s rear body, including the drive track, is typically settled deeper into the snow than is the front end of the vehicle (including the skis) due to the significant weight differential of the vehicle from front to rear. Heretofore, by far the most common way to free the snowmobile at this point has been to have someone assist by standing at the front of the vehicle and pull forward on a ski as best possible given the tractionless environment. Thus, the only assisting force (i.e., in addition to the operation of the entrenched vehicle itself) is often that usually uneven and non—constant force such a person can develop directly at the front of the snowmobile working from the same deep and/or soft snow that has trapped the vehicle in the first place. The task, as may be appreciated, is often not a simple one, taking many attempts to extract the snowmobile. Moreover, it is not unheard of for the assisting person to become an obstacle or even be run over as the vehicle is freed. 
     Various devices and apparatus have heretofore been suggested and or utilized to provide a more reliable, safe and/or simplified process of extrication of snowmobiles when thus bogged in deep and/or soft snow. Such devices have included winching and/or ratcheting mechanisms (see, for example, U.S. Pat. Nos. 5,560,441 and 5,697,597), and standard ropes, cables, tow straps and the like. However, some such apparatus are cumbersome to carry and/or utilize, and may be unduly complex for application in the field and under widely varying conditions. 
     Many of the others, such as standard fiber cordage, cable, straps and the like, while moving the assistant away from the front of the snowmobile and/or allowing use of a companion&#39;s vehicle to provide a pulling force, do little to overcome the problem of developing sufficient assisting force to move a typical 600 lb. entrenched snowmobile in a tractionless environment. These approaches also include no means of evening out the assisting force (i.e., providing constancy of tension) as the vehicle begins to move, and thus backsliding remains a problem. Further consideration of the particular problems and task of freeing entrenched snowmobiles could thus still be utilized. 
     SUMMARY OF THE INVENTION 
     This invention provides improved apparatus and methods for extrication of snowmobiles bogged in deep and/or soft snow. The apparatus is compact, lightweight, and avoids the undue complexity of application in the field and under widely varying conditions that has characterized some heretofore known devices. 
     The apparatus and methods of this invention allow an assisting party to provide a significant pulling force at a distance away from the front of the snowmobile while using the companion&#39;s vehicle to provide additional significant pulling force. Moreover, improvement is achieved in developing assisting forces sufficient to reliably aid movement of a typical 600 lb. entrenched snowmobile in tractionless environments and in providing constancy of assisting forces as the vehicle begins to move. 
     The apparatus and methods both make use of elastic (i.e., significantly stretchable) cords to allow an assisting party to transfer his or her body weight and/or the weight of a companion&#39;s snowmobile into a pulling force of several hundred pounds over a significant distance. The kinetic energy of the cords provides superior tensioning and improved pulling force development over substantially non-elastic materials such as typical cables, fiber robes, straps and the like. 
     The apparatus of this invention provides a unit including such stretchable cord with first and second implements joined to the stretchable cord at positions spaced from one another. A flexible jacket is provided around but unconnected to the stretchable cord and intermediate the first and second implements. The jacket is of material that is relatively more rigid than the stretchable cord. The implements are preferably either first and second couplers or a coupler and a graspable member such as a handle, depending upon application. 
     The preferred apparatus for extricating a bogged snowmobile of this invention includes first and second units each including a stretchable cord. One of the units has first and second couplers joined to the stretchable cord at positions spaced from one another while the other unit has a third coupler and a graspable member joined to the stretchable cord at positions spaced from one another. The first and third couplers are securable at the snowmobile while the second coupler is securable at an anchoring location, the graspable member being provided for use by one applying a stretching force to the second unit. 
     The method for extricating a snowmobile bogged in snow of this invention includes connecting one position of an elastic cord capable of significant elongation with the snowmobile and stretching the elastic cord between the one position and a second position of the elastic cord held at an anchoring location. The bogged snowmobile is then operated to, in combination with the pulling force of the stretched elastic cord, extricate the snowmobile. The stretching of the elastic cord develops up to about 400 lbs. of pulling force and maximum cord elongation of up to at least about 90%. 
     Additional pulling force is developed by connecting one end of a second elastic cord with the snowmobile and manually pulling on the other end of the second elastic cord to stretch the second elastic cord. An additional pulling force of up to at least about 200 lbs. is thus developed. 
     It is therefore an object of this invention to provide improved apparatus and methods for extrication of snowmobiles bogged in deep and/or soft snow. 
     It is another object of this invention to provide snowmobile extricating apparatus that are compact, lightweight, and safe and simple to utilize in the field and under widely varying conditions. 
     It is another object of this invention to provide snowmobile extricating apparatus and methods that allow an assisting party to provide a significant pulling force at a distance away from the front of the snowmobile while using the companion&#39;s vehicle to provide additional significant pulling force. 
     It is still another object of this invention to provide snowmobile extricating apparatus and methods for developing sufficient assisting force to reliably aid movement of a typical entrenched snowmobile in a typical tractionless environment. 
     It is another object of this invention to provide snowmobile extricating apparatus and methods enabling the evening of assisting forces over distance to provide improved constancy of applied tension as the vehicle begins to move from its entrenchment. 
     It is still another object of this invention to provide a unit for extricating a snowmobile bogged in snow including a stretchable cord, first and second implements joined to the stretchable cord at positions spaced from one another, and a flexible jacket around but unconnected to the stretchable cord and intermediate the first and second implements, the jacket being relatively more rigid than the stretchable cord. 
     It is yet another object of this invention to provide an apparatus for extricating a bogged snowmobile including a first unit having a stretchable cord and first and second couplers joined to the stretchable cord at positions spaced from one another, the first coupler being securable at the snowmobile and the second coupler being securable at an anchoring location, and further including a second unit having a stretchable cord with a third coupler and a graspable member joined thereto at positions spaced from one another, the third coupler being securable at the snowmobile and the graspable member for use by one applying a stretching force to the second unit. 
     It is still another object of this invention to provide a method for extricating a snowmobile bogged in snow that includes the steps of connecting one position of an elastic cord capable of significant elongation with the snowmobile, stretching the elastic cord between the one position and a second position of the elastic cord held at an anchoring location, and operating the bogged snowmobile to, in combination with the pulling force of the stretched elastic cord, extricate the snowmobile. 
     It is yet another object of this invention to provide a method for extricating a snowmobile bogged in snow that includes the steps of connecting one end of an elastic cord with the snowmobile and manually pulling on the other end of the elastic cord to stretch the cord and develop additional pulling force. 
     It is still another object of this invention to provide apparatus and methods for extricating a snowmobile bogged in snow that includes utilizing an elastic cord connectable between the snowmobile and an anchoring position and which is capable of accommodating up to about 400 lbs. of pulling force and cord elongation of at least about 20%. 
     It is yet another object of this invention to provide apparatus and methods for extricating a snowmobile bogged in snow that includes utilizing an elastic cord connectable at the snowmobile at one end and graspable at the other end, the cord when pulled being configured to develop up to at least about 200 lbs. of additional pulling force. 
     With these and other objects in view, which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination, arrangement of parts and method substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that changes in the precise embodiment of the herein disclosed invention are meant to be included as come within the scope of the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate a complete embodiment of the invention according to the best mode so far devised for the practical application of the principles thereof, and in which: 
     FIG. 1 is a partial perspective view of a first unit of the apparatus of this invention; 
     FIG. 2 is a partial perspective view of a second unit of the apparatus of this inventions; 
     FIG. 3 is a partial plan view of the unit of FIG. 1 with portions cutaway; 
     FIG. 4 is a partial plan view of the unit of FIG. 2 with portions cutaway; 
     FIG. 5 is a partial exploded view of the unit of FIG. 2; and 
     FIGS. 6A through 6E illustrate methods of using the units of FIGS. 1 and 2 of the apparatus of this invention to extricate a bogged snowmobile. 
    
    
     DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2 show the basic units  15  and  17  of the overall apparatus of this invention. Units  15  and  17  are very similar in many regards, and are employed together to free a bogged snowmobile, depending on conditions and the difficulty of the encountered entrenchment. Each unit  15  and  17  is equipped with selected implement  19  combinations for different applications. Unit  15  includes spaced couplers  21  and  23  at opposite ends thereof. Unit  17  is provided with coupler  25  and graspable member  27  spaced from one another at opposite ends of the unit. 
     While couplers  21 ,  23  and  25  are illustrated herein as closed eye s-hooks, any known coupling mechanism of sufficient strength (breaking strength of 2000 lbs. is more than adequate) could be utilized, such as clasps, bars, links, ties, cables, hasps, fasteners, or the like. Likewise, while graspable member  27  as illustrated herein is a D-handle, any graspable device of sufficient strength could be utilized, such as loops, t-bars, cables, rings, double grasp handles, and so on. 
     Turning to FIGS. 3 through 5, the units are shown in greater detail (FIG. 5 illustrates unit  17 , though much of the disclosure therein pertains as well to unit  15  and will be used herein to illustrate some features of unit  15 ). Unit  15  (FIG. 3) has couplers  21  and  23  joined to opposite ends of multi-line stretchable cord  29  using in part, for example, slip knots  31  and  33  respectively (other means of securing the cord, such as clamps, rivets, collars, or glue, could be utilized). While cord  29  could be constructed of a single heavy line, as shown cord  29  is preferably defined by multiple lines (for example, five lines  35  through  39 —see FIG. 5 for more complete illustration—though fewer or more lines could be utilized) of continuous elastic cord material formed by repeatedly looping the cord material through eyes  41  and  43  of couplers  21  and  23 , respectively, before tying off one end, taking care to assure the constant spacing of the couplers by matching the lengths of the looped lines. 
     Cord material utilized to form cord  29  is preferably between ⅜″ and ½″ diameter Bungee #SPNL-12 stretch cord capable of significant elongation (to at least between about 20% to 90% and preferably up to 100% maximum in use). Utilizing  5  lines of the ½″ material, a breaking resistance of about 3,700 lbs. of pulling force is achieved. Unstretched, cord  29  is between about 4′ and 6′ long (preferably about 5′) between couplers  21  and  23 . 
     Flexible jacket  45  is provided to control, or absorb, retraction forces which may be encountered during use of the unit, for example if a coupler were to dislodge while cord  29  was stretched or if the entrenched snowmobile were to lurch free. Cord  29  is slidably received Through jacket  45 , unconnected thereto. Jacket  45  has an inside diameter selected to allow movement of the cord relative to the jacket (for example, about 1.5″ for the five line cord described above), and is formed of material that is relatively (preferably substantially) more rigid than cord  29 . Corrugated vinyl tubing has been found suited for providing the flexibility and relative rigidity desired to accomplish both storability of the unit and absorbance of retraction forces. Jacket  45  is of a length just slightly less that the unstretched length of cord  29  between couplers  21  and  23 . 
     Collars  47  and  49  are fitted over closed eyes  41  and  43  and knots  31  and  33 , respectively, and have openings  51  and  53 . respectively, at one otherwise closed end of the collars to allow passage therethrough of the s-hook portion of couplers  21  and  23 . Collars  47  and  49  have an outside diameter selected for slidable receipt into jacket  45  when cord  29  is unstretched (for example, between about 1.25″ and 1.5″ using the above examples). The collars may be formed of any material including tape, heat shrink tubing or, preferably, prefabricated vinyl cuffs). 
     Unit  17  (FIGS. 4 and 5) has coupler  25  and graspable handle  27  joined to opposite ends of stretchable cord  55  using in part, for example, slip knots  57  and  59  respectively. Cord  55  is, like cord  29 , defined by multiple lines (for example, five lines  35  through  39 ) of continuous elastic cord material formed by repeated looping. Unstretched, cord  55  is between about 1.5′ and 4′ long between couplers  25  and  27  (preferably about 2′). Flexible jacket  61  is constructed and utilized like jacket  45 , as are collars  63  and  65 . 
     Graspable D-handle  27  is held on eye bolt  67  by nut  69  with washer  71  provided to assure free rotation of the handle. Eye  73  of bolt  67  serves the same function at graspable member  27  as do eyes  41  and  43  at couplers  21 ,  23  and  25 . 
     In use, as illustrated in FIGS. 6A through 6E, unit  15  is connected by coupler  21  to bogged snowmobile  75 , at ski  77  for example. Coupler  23  is connected, with cord  29  preferably in the unstretched state, to a companion&#39;s snowmobile  79 , for example at the vehicles rear tow bar. The companion then moves snowmobile  79  forward, stretching cord  29  as much as 5′ (100% elongation). This may apply more than 400 lbs. of pulling force at the front end of snowmobile  75  (depending upon the vehicles involved). The companion may then stop and lock his vehicle&#39;s brake and leave the vehicle, the pulling force thus remaining constant though unattended. Alternatively, where necessary instead of using another vehicle for an anchor, the cord could be stretched and connected to any available anchoring location by the entrenched vehicle&#39;s user. 
     Unit  17  is connected by coupler  25  to snowmobile  75 , for example at the other ski  81 . The companion grasps handle  27 . and exerts his body to stretch cord  55  of unit  17 , preferably at a slightly upward angle. An additional pulling force of over 200 lbs. can be exerted on vehicle  75  in this fashion. While both the unattended pulling force and the attended pulling force are being exerted, the operator of snowmobile  75  operates his vehicle, thus using the vehicle&#39;s track to create a pushing force. As snowmobile  75  begins to move, constant pulling force is maintained by the inherent retraction of the stretched elastic cords  29  and  55 , thus avoiding backsliding. 
     The combined pulling forces of units  15  and  17 , which nears or exceeds the weight of most standard snowmobiles, has proved very effective in assisting movement of entrenched snowmobiles, allowing the vehicle to essentially drive itself out of its entrenchment. In some less problematical situations, either one of units  15  and  17  by itself may be sufficient to aid extrication of a bogged snowmobile.