Abstract:
A kingpin adapter is provided having an upper wall and a lower wall that are affixed to each other through side walls. The upper and lower walls have a kingpin aperture and a hitch ball aperture that is spaced from and parallel to the kingpin aperture. The kingpin aperture receives a kingpin and the adapter is affixed to the kingpin using pins that extend through the side walls and extend through a portion of the undercut in the kingpin. The upper wall has jack screws that extend through to contact a skid plate that is affixed to the kingpin. The jack screws affix optional adjustable fences that rotationally constrain the skid plate by contacting lateral edges of it.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/240,216, filed Oct. 12, 2015, the disclosures of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Traditional kingpin and fifth wheel hitches used on recreational vehicles are similar to those used on tractor trailer combinations and have the same disadvantages. The kingpin must be at a very specific height for its entry into the fifth wheel hitch. Further, the operator of the vehicle must back into the kingpin when it is at its proper height. Performing this task can be nearly impossible in locations other than a large, level, and smooth surface. 
         [0003]    Another problem with traditional kingpin and fifth wheel hitches is the constraint of the trailer to rotate in a single plane. In a traditional fifth wheel hitch, the kingpin is locked with a jaw that restrictively limits the out of plane movement with respect to the hitch. While this may work for a tractor trailer combination, it is extremely undesirable for smaller vehicles. Traveling over uneven terrain will necessitate out of plane movement. A previous attempt to provide out of plane movement with a fifth wheel hitch has been to provide a pivot pin below the fifth wheel plate. This allows the entire fifth wheel plate to pivot, but adds significant weight and complexity to the hitch. A more flexible system is needed for an ordinary recreational user that may lack the requisite skill to align a kingpin in a fifth wheel hitch. Further, a device is needed to allow an existing trailer having a kingpin to be adapted to the new flexible system. 
       SUMMARY OF THE INVENTION 
       [0004]    The present disclosure describes an adapter that can be attached to a kingpin trailer and used with a hitch ball receiver. The device is selectively lockable to the kingpin and incorporates jack screws that apply biased pressure against the kingpin. The kingpin is received by a kingpin aperture. Transverse pins lock the device to an undercut groove on the kingpin. A ball shaft has a spherical surface that is sized to mate with a vehicle mounted receiver. The ball shaft has a shaft portion that is held by an adapter with the spherical surface protruding downwardly. The ball and adapter may be integral and permanently affixed to each other. Another aperture holds the ball shaft that is offset from the kingpin. The ball assembly is then received by a vehicle-mounted receiver to mate the kingpin trailer to the hitch on the vehicle. Alignment and anti-rotation walls extend upwardly from the top surface of the adapter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    A preferred embodiment of this invention has been chosen wherein: 
           [0006]      FIG. 1  is a top isometric view of the adapter as affixed to a hitch and kingpin; 
           [0007]      FIG. 2  is a front view of the adapter shown in  FIG. 1  as affixed to a hitch and kingpin; 
           [0008]      FIG. 3  is a bottom isometric view of the adapter shown in  FIG. 1-2 ; 
           [0009]      FIG. 4  is a top isometric view of the adapter shown in  FIGS. 1-3 ; 
           [0010]      FIG. 5  is a top isometric view of the adapter shown in  FIGS. 1-4 ; 
           [0011]      FIG. 6  is a bottom view of the adapter shown in  FIGS. 1-5 ; 
           [0012]      FIG. 7  is a rear view of the adapter shown in  FIGS. 1-6  as affixed to a kingpin; 
           [0013]      FIG. 8  is a side section view taken about line  6 - 6  in  FIG. 7 ; 
           [0014]      FIG. 9  is a front view of the adapter as affixed to a hitch and kingpin; 
           [0015]      FIG. 10  is a bottom isometric view of the adapter shown in  FIG. 9 ; 
           [0016]      FIG. 11  is a top isometric view of the adapter shown in  FIGS. 9-10 ; 
           [0017]      FIG. 12  is a bottom view of the adapter shown in  FIGS. 9-11 ; and 
           [0018]      FIG. 13  is a side section view taken about line  13 - 13  in  FIG. 9 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]      FIG. 1  shows a truck/trailer attachment mechanism. The entire trailer is not shown, but is commonly an RV, utility trailer, or other tow-behind trailer. The common method of towing a trailer is a fifth-wheel attachment. Compared to a bumper-mounted hitch, it offers more stability, better towing, and has a superior connection between the trailer and the towing vehicle. This stability arises from the location of the trailer tongue weight being over the rear axle. The adapter  10  described herein is designed to attach between the trailer&#39;s pin box  12  and a bed-mounted hitch  14 . The purpose of the adapter  10  is to convert a standard kingpin  18  as shown in  FIG. 8  to a downwardly protruding hitch ball  84  that serves as a more effective coupler than a standard kingpin  18 . The trailer has a pin box  12  with a kingpin  18  that extends downwardly from a skid plate  16 . The kingpin  18  is securely affixed to the trailer and is commonly used to attach the RV to a towing vehicle. A bed-mounted hitch  14  has a receiver  15  that affixes to the towing vehicle, usually a truck. 
         [0020]    The pin box  12 , skid plate  16 , and kingpin  18  are normally affixed to the trailer through welding, bolts, rivets, or other mechanical fastening. The skid plate  16  has a lower surface  20  that is typically flat where the kingpin  18  protrudes. The lower surface  20  has lateral edges  21  that define the width of the skid plate  16 . As shown in  FIG. 8 , the kingpin  18  is affixed to the skid plate  16  and is cylindrically shaped with a major diameter  24 . An undercut  22  with a minor diameter  25  is located near the terminal end  26 . The undercut  22  ends at a shoulder surface  27  that is nearest the terminal end  26 . A small portion of the major diameter  24  remains below the undercut  22 . 
         [0021]      FIG. 1  shows the context and environment of a bed-mounted hitch  14 , for use with the hitch ball  84  of the adapter  10 . The bed-mounted hitch  14  has a receiver tube with a lead-in funnel that is for guiding a hitch ball  84  into the receiver tube, where it can be affixed to the hitch  14 . 
         [0022]    The adapter  10  is shown by itself in  FIGS. 3-6 . The top wall  60  is typically made from and shown as a piece of flat sheet metal that has a kingpin aperture  62  and a hitch ball aperture  64 . As shown, both apertures  62 ,  64  are circular, but other shapes are possible. The top wall  60  has a series of jack screws  66  that are threaded into the top wall  60  in tapped holes  68 . The jack screws  66 , when tightened, protrude above the uppermost surface  65  of the top wall  60 . Jamb nuts  54  lock the jack screws  66  in place. 
         [0023]    The adapter  10  has a bottom wall  70  with a kingpin aperture  72  and a hitch ball aperture  74 . As shown in  FIG. 3 , the coaxial alignment of the kingpin apertures  62 ,  72  define a cylindrical projection through the adapter  10 . As shown, both apertures  72 ,  74  are circular but other shapes are possible. The coaxial alignment of the hitch ball apertures  64  and  74  define a projection through the adapter  10  that is spaced from and parallel to the cylindrical projection from kingpin apertures  62  and  72 . Extending between the top wall  60  and the bottom wall  70  are side walls  76 ,  78  that set the parallel spacing between the top wall  60  and the bottom wall  70 . Reinforcing gussets  80  reinforce the side walls  76 ,  78  and the top wall  60 . As shown, the side walls  76 ,  78  and bottom wall  70  are formed from the same flat sheet metal, but it is contemplated that these are separate pieces. The side walls  76 ,  78  have opposing hitch ball locking holes that align with a transverse hole when a hitch shaft  82  is located in the hitch ball apertures  64 ,  74 . 
         [0024]    The hitch shaft  82  has a ball portion  84  that extends downwardly from it. Extending through the diameter of the hitch shaft  82  is a transverse hole  88 . The transverse hole  88  is adapted to receive a pin  38  as shown in  FIG. 2  that extends through the side walls  76 ,  78  at hitch ball locking holes. The pin  38  is bent downwardly at one end and cannot be passed through its corresponding locking holes. The opposite end of the pin  38  receives a clip  40  that holds the pin  38  in the transverse hole and locking holes on the side walls  76 ,  78 . It is contemplated that the clip  40  could be replaced with an E-clip, snap ring, or other mechanical fastening device. Once the pin  38  is in place and securely locking the hitch shaft  82  to the adapter  10 , jack screws  34 ,  36  can be tightened against the hitch shaft  82 . This prevents the hitch shaft  82  from rattling or being loose. The jack screws  34 ,  36  are supported by an end wall  42 . It is contemplated that the hitch shaft  82  may be permanently affixed to the adapter  10  by welding or otherwise affixing it to the adapter  10 . The end wall  42  rigidifies and bridges the side walls  76 ,  78  to the top and bottom walls  60 ,  70 . 
         [0025]    As is shown in  FIG. 8 , the kingpin  18  is received by the kingpin apertures  62 ,  72  in the top and bottom walls  60 ,  70  and is retained by a first locking pin  48  and a second locking pin  50 . As shown, the second locking pin  50  has a sleeve  52 . The sleeve  52  provides reinforcement and strengthening of the second locking pin  50 . The first locking pin  48  passes through holes in the side walls  76 ,  78 . The side walls  76 ,  78  and the second locking pin  50  passes through holes in the side walls  76 ,  78 . The holes are located adjacent to the undercut  22  such that the locking pins  48  and  50  intersect the cylindrical kingpin aperture created by apertures  62 ,  72  and fit into the undercut  22  and lock the kingpin  18  from being removed from the kingpin apertures  62 ,  72 . The locking pins  48 ,  50  are shown as bolts but a smooth pin similar to pin  38  (shown in  FIG. 3 ) is contemplated. Because the kingpin  18  and undercut  22  shown in  FIG. 8  may not perfectly align with the outside diameters of the locking pins  48 ,  50 , the jack screws  66  can be tightened to contact the lower surface of the skid plate  20  and bias the kingpin  18  away from the adapter  10 , and therefore firmly contact the edge of the undercut  22  against the outside diameters of the pins  48 ,  50 . This prevents the adapter  10  from rotating with respect to the pin box  12  as shown in  FIGS. 1, 2, and 8 . 
         [0026]    To install the adapter  10  onto an existing kingpin  18  and pin box  12 , the following steps are performed. First, the jack screws  66  are retracted sufficiently to be near or below the upper surface of the top wall  60 . Next, the pins  48 ,  50 , and the sleeve  52  are removed. This allows a clear opening for the terminal end  26  of the kingpin  18  to be passed through both the kingpin apertures  62  and  72 . Once the undercut  22  is lined up with the holes as shown in  FIG. 1 , the first locking pin  48  can be inserted and secured. Also, the sleeve  52  can be inserted between the walls  76 ,  78  and the second locking pin  50  can be passed through the center of it. At that point, the jack screws  66  can be tightened against the skid plate  16 , specifically the lower surface  20 . The jamb nuts  54  are then tightened. This secures the adapter  10  to the trailer. Removal is the reverse of installation. The user may exchange different sized balls if needed. If the user desires to remove the hitch shaft  82 , the jack screws  34 ,  36  are loosened sufficiently to no longer apply biased pressure against the major diameter  24 . The pin  38  is then removed by first removing the clip  40  and sliding the pin  38  out through the transverse holes. To insert a new hitch shaft  82 , the user reverses the steps of removal. 
         [0027]    The adapter  100  may incorporate adjustable fences  122 ,  124  as shown in  FIGS. 9-13 . The adjustable fences  122 ,  124  prevent rotation of the adapter  100  in the event that the jack screws  166  are not properly tightened against the skid plate  16 . The embodiment of the adapter  100  is shown in  FIGS. 10-13  and includes the same top wall  160 , bottom wall  170 , and hitch shaft  182 . The top wall  160  is typically made from and shown as a piece of flat sheet metal that has a kingpin aperture  162  and a hitch ball aperture  164 . As shown, both apertures  162 ,  164  are circular, but other shapes are possible. The top wall  160  has a series of jack screws  166  that are threaded into the top wall  160  in tapped holes  168 . When the jack screws  166  and jamb nuts  154  are tightened, the adjustable fences  122 ,  124  are secured and the jack screws  166  also protrude above the uppermost surface  165  of the top wall  160 . To prevent rotation, the adjustable fences  122 ,  124  are adjusted to come into contact with the lateral edges  21  of the skid plate  16  before the jamb nuts  154  are tightened. The adjustable fences  122 ,  124  are formed from a slotted wall portion  116 ,  126  that are affixed to a corresponding vertical wall portion  118 ,  128 . The slotted wall portions  116 ,  126  have a series of slots  120  that allow the adjustable fences  122 ,  124  to adjust. It is contemplated that the adjustable fences  122 ,  124  may be fixed to the top wall through other fasteners separate from the jack screws  166  and jamb nuts  154 . 
         [0028]    The adapter  100  has a bottom wall  170  with a kingpin aperture  172  and a hitch ball aperture  174 . The coaxial alignment of the kingpin apertures  162  and  172  define a cylindrical projection through the adapter  100 . As shown, both apertures  172 ,  174  are circular but other shapes are possible. The coaxial alignment of the hitch ball apertures  164  and  174  define a projection through the adapter  10  that is spaced from and parallel to the cylindrical projection from kingpin apertures  162  and  172 . It is contemplated that hitch ball apertures  164  and  174  could be a shape other than circular. Extending between the top wall  160  and the bottom wall  170  are side walls  176 ,  178  that set the parallel spacing between the top wall  160  and the bottom wall  170 . Reinforcing end walls  180  reinforce the side walls  176 ,  178  and the top wall  160 . As shown, the side walls  176 ,  178  and bottom wall  170  are formed from the same flat sheet metal, but it is contemplated that these are separate pieces. 
         [0029]    The hitch shaft  182  has a ball portion  184  that extends downwardly from it. The hitch shaft, as shown, is permanently affixed to the adapter  100  by welding or other permanent fixation method. The end walls  180  rigidify and bridge the side walls  176 ,  178  and the top and bottom walls  160 ,  170 . 
         [0030]    The kingpin  18  is received by the kingpin apertures  162 ,  172  in the top and bottom walls  160 ,  170  and is retained by a first locking pin  148  and a second locking pin  150 . As shown, the second locking pin  150  has a sleeve  152 . The sleeve  152  provides reinforcement and strengthening of the second locking pin  150 . The first locking pin  148  passes through holes in the side walls  176 ,  178 . The side walls  176 ,  178  and the second locking pin  150  passes through holes in the side walls  176 ,  178 . The holes are located adjacent to the undercut  22  such that the locking pins  148  and  150  intersect the cylindrical kingpin aperture created by apertures  162 ,  172  and fit into the undercut  122  and lock the kingpin  18  from being removed from the kingpin apertures  162 ,  172 . The locking pins  148 ,  150  are shown as bolts but a smooth pin similar to pin  38  (shown in  FIG. 3 ) is contemplated. Because the kingpin  18  and undercut  22  shown in  FIG. 13  cannot perfectly align with the outside diameters of the locking pins  148 ,  150 , the jack screws  166  can be tightened to contact the lower surface  20  and bias the kingpin  18  away from the adapter  100 , and therefore firmly contact the edge of the undercut  22  against the outside diameters of the locking pins  148 ,  150 . This prevents the adapter  100  from rotating with respect to the pin box  12 . 
         [0031]    To install the adapter  100  onto an existing kingpin  18  and pin box  12 , the following steps are performed. First, the jack screws  166  are retracted sufficiently to be near or below the upper surface of the top wall  160 . Next, the locking pins  148 ,  150 , and the sleeve  152  are removed. This allows a clear opening for the terminal end  26  of the kingpin  18  to be passed through both the kingpin apertures  162  and  172 . Once the undercut  22  is lined up with the holes as shown in  FIG. 1 , the pin  148  can be inserted and secured. Also, the sleeve  152  can be inserted between the walls  176 ,  178  and the locking pin  150  can be passed through the center of it. At that point, the adjustable fences  122 ,  124  are brought into contact with the lateral edges  21  of the skid plate  16 . Once the adjustable fences  122 ,  124  are in position, the jack screws  166  can be tightened against the skid plate  16 , specifically the lower surface  20 . Lastly, the jamb nuts  154  are tightened. This secures the adapter  100  to the trailer. Removal is the reverse of installation. 
         [0032]    It is understood that while certain aspects of the disclosed subject matter have been shown and described, the disclosed subject matter is not limited thereto and encompasses various other embodiments and aspects. No specific limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. Modifications may be made to the disclosed subject matter as set forth in the following claims.