Abstract:
A portable winch system mounted to a standard trailer hitch tow ball of a vehicle permits steep incline pulling angles of the winch without cutting into the neck portion of the tow ball. To achieve a broad range of inclination angles, the cup plate (socket that fits over the tow ball) and/or the ball-locking portion of the winch system includes relieved neck-clearance areas. In some embodiments, the cup plate and/or ball-locking mechanism includes neck contact points that are softer than the material of the tow ball.

Description:
FIELD OF THE INVENTION 
   The subject invention generally pertains to winches and more specifically to a winch mountable to a tow ball normally used for a trailer hitch. 
   BACKGROUND OF RELATED ART 
   U.S. Pat. No. 6,386,514 discloses how a winch can be attached to a vehicle&#39;s trailer hitch ball, also known as a tow ball. Examples of vehicles include, but are not limited to, cars trucks, ATVs, snowmobiles, buggies, airboats, tanks, wreckers, tow trucks, logging equipment, construction equipment, utility equipment, agricultural equipment, military vehicles, and rescue equipment. Attaching a winch to a vehicle, as shown in the &#39;514 patent, can be useful in situations where the winch is pulling in a direction that is generally horizontal or level with the vehicle. In some cases, however, the vehicle may be stuck in a deep ditch or gully, and a winch might need to pull upward at a significant incline in order to pull the vehicle out. 
   A winch pulling at an upward angle, rather than horizontally, can apply a damagingly high bending moment on the vehicle&#39;s chassis, bumper, and receiver and ball mount. The receiver and ball mount is the hardware that typically connects the tow ball to the vehicle. If a cup plate (also known as a trailer coupler, which is the socket that fits over the tow ball) is tilted up or down relative to the tow ball, the ball locking mechanism within the cup plate or edges on the cup plate itself can possibly cut into the neck portion of the tow ball and do permanent damage. 
   Consequently, a need exists for a safer way of quickly connecting a winch to a vehicle&#39;s tow ball. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a winch system that can be safely coupled to a vehicle&#39;s tow ball. 
   Another object of some embodiments is to provide a ball-engaging cup plate, to which the winch is mounted, with relatively soft edges that avoid cutting into the neck portion of the tow ball. 
   Another object of some embodiments is to make the edges with a Brinell hardness of less than 100 BHN, thereby reducing the likelihood of the edges scratching or cutting into a tow ball made of steel. 
   Another object of some embodiments is to provide a cup plate with one or more neck-clearance notches that enable the cup plate to pivot at steeper angles relative to the tow ball. 
   Another object of some embodiments is to cover one or more ball-engaging edges of a cup plate with relatively soft bumpers. 
   Another object of some embodiments is to attach a shackle to a cup plate, wherein the shackle is pivotal to serve the dual purpose of enabling a cradle sling hookup and providing a centrally balanced carrying handle. 
   Another object of some embodiments is to attach a hook of a winch from one vehicle to a shackle that is on a cup plate mounted to a second vehicle. 
   One or more of these and/or other objects of the invention are provided by a winch mountable to a tow ball, wherein the winch system includes means for accommodating relatively steep pulling angles of the winch. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view partially in cross-section showing a winch system in a lock position. 
       FIG. 2  is a view similar to  FIG. 1  but showing the winch system in a release position. 
       FIG. 3  is a view similar to  FIG. 1  but showing the winch system tilted at its upper limit of inclination. 
       FIG. 4  is a view similar to  FIG. 1  but showing the winch system tilted at its lower limit of inclination. 
       FIG. 5  is a left end view of  FIG. 1 . 
       FIG. 6  is a side view showing the winch system in a cradle sling hookup. 
       FIG. 7  is a perspective view of a winch system component. 
       FIG. 8  is a perspective view of another winch system component. 
       FIG. 9  is a view similar to  FIG. 3  but showing an alternate embodiment. 
       FIG. 10  is a view similar to  FIG. 4  but showing the embodiment of  FIG. 9 . 
       FIG. 11  is a view similar to  FIG. 1  but showing the embodiment of  FIGS. 9 and 10 . 
       FIG. 12  is a side view showing one example of the winch system in use. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1-6  show a winch system  10  connected to a tow ball  12  of a vehicle  14 . Although there are many ways of connecting a tow ball to a vehicle, in the illustrated example, vehicle  14  includes a receiver  16  in which a ball mount  18  is inserted. Tow ball  12 , in this example, includes a neck portion  20  and a base flange  22  bolted to ball mount  18 . 
   Winch system  10  comprises a cup plate  24  having a front end  26  and a back end  28 . Cup plate  24  defines a hollow interior  30 , and front end  26  defines a ball-receiving socket  32  with a rim  34 , wherein ball-receiving socket  32  is an extension of the hollow interior  30 . 
   Winch system  10  also includes a winch  36  mounted to an upper surface  38  of cup plate  24 . Although  FIG. 5  shows winch  36  with a cable  40  ( FIGS. 5 and 6 ) wrapped around a drum  42  powered by an electric motor  44 ; alternatively, winch  36  could be powered manually, hydraulically or pneumatically. Also, cable  40  could instead be a rope, chain, strap or any other flexible elongate member. 
   To selectively lock or release tow ball  12 , winch system  10  includes a draw pin  46  having an upper end  48  and a lower end  50 . Lower end  50  extends into hollow interior  30  of cup plate  24 . A lever  52  coupled to upper end  48  of draw pin  46  is manually pivotal about a pin  54  such that a cam end  56  of lever  52  acts upon surface  38  to selectively raise and lower draw pin  46  between a lock position ( FIG. 1 ) and a release position ( FIG. 2 ). A ball-engaging retainer  58  is connected to lower end  50  of draw pin  46  so that when draw pin  46  is in the lock position of  FIG. 1 , a lower lip  60  of retainer  58  engages tow ball  12  to trap tow ball  12  within ball-receiving socket  32 . When draw pin  46  is in the release position of  FIG. 2 , retainer  58  releases tow ball  12  from within ball-receiving socket  32 . A compression spring  62  helps hold cam end  56  down against upper surface  38  and urges retainer  58  away from ball  12  when draw pin  46  is in the release position. 
   Although the actual design of retainer  58  may vary, in some embodiments, retainer  58  comprises a ball lock  64  ( FIG. 7 ) and an internally threaded nut  66  ( FIG. 8 ). In this example, ball lock  64  is the part of retainer  58  that engages and captures tow ball  12  in the lock position. Nut  66  is screwed onto lower end  50  of draw pin  46  so that pin  46  can pull ball lock  64  upward upon pin  46  moving from the release position of  FIG. 2  to the lock position of  FIG. 1 . When ball lock  64  is lifted by draw pin  46 , ball lock  64  pivots about a horizontal pin  68  that is affixed to the two sidewalls  70  of cup plate  24 . 
   Since a winch mounted to a vehicle might be used for pulling the vehicle up and out of a ditch or gully, the winch&#39;s angle of pull can vary widely and be quite steep. To accommodate such angles, winch system  10  is designed to allow cup plate  24  to pivot between the positions of  FIGS. 3 and 4 . Referring to  FIGS. 5 ,  6  and  7  rim  34  has a first neck-clearance notch  72 , and/or lower lip  60  has a second neck-clearance notch  74 , which allow cup plate  24  to pivot farther than what would otherwise be possible. 
   To prevent neck portion  20  of tow ball  12  from being damagingly scratched or cut by rim  34  of cup plate  24 , lower lip  60  of ball lock  64 , or a lower lip  76  of nut  66 ; winch system  10  includes one or more safety features. In some embodiments, the upward inclination of cup plate  24  is limited by rim  34  contacting neck  20  at point  78 , as shown in  FIG. 3 . Point  78  is also shown in  FIGS. 5 and 6 . To protect neck  20  from damage, rim  34  at point  78  can be of a material that is softer than a standard steel tow ball. Rim  34 , for example, can be made of a material having a Brinell hardness of less then 100 BHN, which can be achieved with various materials including, but not limited to, aluminum, copper, and alloys thereof. Lower lip  76  of nut  66 , which is show engaging neck  20  at point  80  in  FIG. 4 , can also be made of a material having a Brinell hardness of less then 100 BHN. Point  80  is also shown in  FIG. 8 . 
   If instead of nut  66 , a winch system  82  includes a standard hex nut  84 , as shown in  FIGS. 9-11 . In this example, lower lip  60 ′ of ball lock  64 ′ engages neck  20  at point  86 , as shown in  FIG. 10 . A comparable point  86 ′ is shown in  FIG. 7 . In this case, neck  20  can still be protected by making lower lip  60 ′ of ball lock  64 ′ of a material having a Brinell hardness of less then 100 BHN. Although the entire ball lock  64 ′ can be made of a relatively soft material, in some cases, ball lock  64 ′ is made of steel with an added soft bumper  88  that has a Brinell hardness of less than 100 BHN. Examples of acceptable bumper materials include, but are not limited to, polymeric materials, aluminum, copper, and various aluminum and copper alloys. 
   A bumper  90  similar to bumper  88  can also be added to neck-clearance notch  72 ′ on cup plate  38 , as shown in  FIGS. 9-11 . 
   Winch systems  10  and  82  preferably include a hook-receiving ring  92  on cup plate  24  to serve as a convenient carrying handle and to facilitate a cradle sling hookup where cable  40  can wrap around an anchor  94  (e.g., a tree or pole, or sheave or pulley connected thereto) and hook back onto ring  92 , as shown in  FIG. 6 . Such a cradle sling hookup basically doubles the pulling force provided by winch  36 . Positioning ring  92  at the back end of cup plate  24  with winch  36  being generally between ring  92  and lever  52  (or between ball  12  and ring  92 ) provides even load distribution with minimal strain on cup plate  24 . Ring  92  is preferably pivotal (e.g., a shackle) so that ring  92  can extend outward for carrying and cradle sling use, and hang downward when not in use. 
     FIG. 12  shows another example of how the winch system can be used. In this example vehicle  14  and winch system  10  are being used for pulling a second vehicle  14 ′ up and out from a ditch or gully. A hook  96  from winch  36  of vehicle  14  hooks onto a ring  92 ′, which is connected to a cup plate  24 ′ of vehicle  14 ′. Although  FIG. 12  shows that a winch is not mounted to cup plate  24 ′, mounting a winch to cup plate  24 ′ can certainly be done if so desired. 
   Although the invention is described with respect to a preferred embodiment, modifications thereto will be apparent to those of ordinary skill in the art. The scope of the invention, therefore, is to be determined by reference to the following claims: