Abstract:
An adaptor for securing a fifth wheel hitch to the bed of a towing vehicle is described. The fifth wheel hitch is typically part of a larger assembly having attachment lugs configured to be removably secured to receptacles in mounting rails permanently attached to the bed of the towing vehicle. Newer towing vehicles are provided with recessed sockets in the vehicle bed, rather than permanently mounted rails, to eliminate obstructions to placement of cargo in the bed. The present invention is, therefore, an adaptor for securing existing fifth wheel assemblies to these newer towing vehicles.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/383,090, filed on Sep. 15, 2010. 
    
    
     FIELD OF THE INVENTION 
     The present invention pertains to systems for mounting fifth wheel trailer hitches to towing vehicles, and more particularly, to systems for adapting older style fifth wheel assemblies to newer style vehicles. 
     BACKGROUND 
     It is common practice to tow trailers, recreational vehicles and the like behind and utilizing automobiles and trucks. For relatively small and lightweight towed vehicles or trailers, conventional Class 1, Class 2 and Class 3 ball-type hitches are commonly mounted to vehicle bumpers and frames. However, as the size and weight of the trailer increases, it is essential that the loads imposed on the vehicle by the trailer be adequately secured and distributed. 
     Typical of the problem presented is the towing of a large and heavy trailer behind a conventional pickup truck. In these applications, in place of a ball hitch, it is known to use a “fifth wheel” trailer hitch assembly, similar, in many respects, to the fifth wheel hitch coupling used by large highway cargo-hauling tractor/trailers. By using a fifth wheel type trailer hitch mounted directly over or ahead of the rear axle of a pickup truck, such a vehicle can adequately accommodate large and heavy trailers. 
     It is well known, therefore, to install fifth wheel-type hitches in the beds of pickup trucks, so that the trailer tongue (or “gooseneck”) is secured to the towing vehicle bed at the proper longitudinal axes of the vehicle to optimize the placement of the loads imposed by the trailer. Additionally, forward placement of the tongue of the towed trailer in relation to the towing vehicle&#39;s wheelbase improves the towing characteristics of the trailer, helping to minimize undesirable sway and oscillation. 
     Numerous techniques for securing the fifth wheel to the truck bed have been disclosed. See, for example, U.S. Pat. No. 6,158,761, to King and U.S. Pat. No. 6,557,883 to Linger, et al. Typical systems involve the placement of reinforcing mounting rails on the upper surface of the pickup truck bed, and providing such mounting rails with receptacles which will engage corresponding lugs on the fifth wheel assembly. This configuration is desirable so that the fifth wheel assembly can be readily removed from the towing vehicle, to open the cargo area of the towing vehicle for load carrying and tasks. Numerous similar methodologies have been used in the past, all designed to achieve the same goals, i.e., removability so that the vehicle can be used as a cargo-carrying vehicle, and sturdiness, so that when used as a towing vehicle, the appropriate support is provided by the towing vehicle&#39;s bed and mounting rails. 
     While these prior art systems have worked adequately, it has long been recognized that the presence of permanently mounted support rails in the bed of the pickup truck is still undesirable, in that these mounting rails present some obstacle to the loading and unloading of the bed of the vehicle. Recognizing this limitation, at least one motor vehicle manufacturer has designed and incorporated into its pickup truck a recessed mounting system. Such a system is disclosed in U.S. Pat. No. 7,121,573 to Lindeman, et al. This system moves the supports for the fifth wheel assembly to the underside of the truck bed, and provides the supports with recessed receptacles or sockets which are substantially flush with the truck bed upper surface. In this fashion, the truck bed remains relatively unobstructed when the fifth wheel assembly is not installed. 
     Fifth wheel trailer hitch assemblies are, not unexpectedly, expensive because of their mechanical complexity as well as the requirement that they be extremely sturdy. The newer fifth wheel mounting scheme taught by Linderman suffers from the requirement that a specialized fifth wheel hitch assembly be utilized, so that the fifth wheel assembly-mounting scheme is complimentary with the array of mounting sockets installed in the truck bed. For obvious reasons, owners of older fifth wheel assemblies would prefer not to have to incur the expense of buying an entire new assembly, and discarding an older style. 
     A need exists, therefore, for adapting older style fifth wheel trailer hitches to newer style truck bed mounting arrays. The present invention addresses this need. 
     SUMMARY 
     The invention is an adaptor which will interface with a conventional fifth wheel trailer hitch assembly and a modern pickup truck hitch-mounting configuration. The invention comprises a base plate and framework. Mounted to the base plate are a plurality of locking key inserts which engage the recessed receptacles in a pickup truck bed. The assembly is further provided with a set of mounting receptacles which are designed to engage the mounting lugs of an older style fifth wheel hitch assembly. The invention is further provided with quick release means by which the mounting lugs of the invention may be reliably yet removably secured to the truck bed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
         FIG. 1  is a perspective view of the present invention. 
         FIG. 2  is a perspective view of the invention with a fifth wheel assembly mounted thereto. 
         FIG. 3  is an exploded perspective view of the invention as installable in the bed of a typical pickup truck, and showing a typical fifth wheel assembly in mounting alignment thereto. 
         FIG. 4  is a perspective bottom view of the invention depicting details of the mounting mechanism. 
         FIG. 5  is a close-up view of the mechanism for locking the invention in place in a pickup truck bed. 
         FIG. 6  is a perspective view of a prior art mounting system, showing typical mounting rails in a truck bed and a typical fifth wheel assembly. 
     
    
    
     DETAILED DESCRIPTION 
     A preferred embodiment of the invention will be best understood by reference to  FIGS. 1-6  attached hereto, and the corresponding numerals as herein explained. A conventional fifth wheel assembly  100  comprises a fifth wheel  110  having an arcuate plate  112  and an entry  114 . The upper surface of the arcuate plate  112  forms a bearing surface  116 . Adjacent to the entry  114  is a latch  118  which may be rotated by operating lever  120 . In this fashion, a pin projection (not shown) from a trailer tongue (not shown) is inserted into the entry  114  and latched into position by latch  118  utilizing operating lever  120 . This results in the complimentary bearing of a portion of the trailer tongue (not shown) on arcuate plate  112 . The fifth wheel  110  is provided with a support further comprising a mounting frame  124  integral with side plates  126 , and secured to end plates  128 . Mounting lugs  130  for mounting the entire assembly are provided with releasable fasteners  132 . In a typical prior art installation as shown in  FIG. 6 , mounting rails  134  are provided with rectangular receptacles  135  into which mounting lugs  130  of fifth wheel assembly  100  slidably fit. This description of the prior art is not exhaustive, and there are a number of different configurations by which the mounting lugs  130  may engage mounting rails  134 . In most known prior art configurations, however, mounting rails  134  remain permanently affixed to the truck bed  139  of the towing vehicle. 
     Newer towing vehicles, as depicted in U.S. Pat. No. 7,121,573, are provided with support members  140  mounted below the truck bed, and receptacles  142  pass through the truck bed into the support members. The fifth wheel assembly itself is provided with support legs, on the distal ends of which are inserts which are designed to engage the receptacles  142  above described. 
     The present invention is designed to permit an older style fifth wheel assembly  100  having mounting lugs  130  to be safely and securely mounted to the truck bed  139  mounting of the type described in the &#39;573 patent. To achieve this result, an adaptor assembly  10  is constructed from an essentially rectangular base plate  12 , typically of a high strength material such as steel. To reduce the overall weight of the invention, one or more lightening holes  14  may be provided in the base plate  12 . Passing through holes in the base plate are a plurality of rotatable feet  16 , spaced at distances corresponding to the configuration, array and distances of the receptacles  142  of the type disclosed in the &#39;573 patent. Base plate  12  is provided with reinforcing rails  18  and mounting rails  20 . Rectangular receptacles  22  are provided in mounting rails  20 . Mounting rails  20  are also provided with openings  28  into which may be placed releasable fasteners  132 . The mounting lugs  130  of a typical fifth wheel trailer hitch assembly are provided with openings  138 . As will be appreciated from examination of  FIGS. 1-6 , placement of the rectangular mounting lugs  130  of the fifth wheel assembly  100  into the rectangular receptacles  22  of mounting rails  20  positions openings  138  in alignment with corresponding openings  28  in the mounting rails  20 , whereby releasable fasteners  132  may be inserted through the mounting rails  20  and the mounting lugs  130  to secure the fifth wheel assembly  100  at the mounting rails. Releasable fasteners  132  may be threaded-type fasteners, or quick release fasteners of a variety of well-known types, to simplify attachment of the fifth wheel assembly  100  to the invention. 
     The invention is provided with handgrips  26  to facilitate movement and positioning of the invention in relation to the truck bed  139  in which the invention will be placed. 
     It will be appreciated from further examination of  FIG. 4  that the rotatable feet  16  are provided with keyed ends  29 . The keyed ends  29  are unitary with the shafts  30 , which are in turn secured to locking handles  32  utilizing nut ends  34 . A through bore is provided in each shaft  30  to accept a locking pin  36 . In this fashion, rotation of locking handles  32  insures rotation of shaft  30  and rotatable of keyed ends  29  of the rotatable feet  16 . 
     The receptacles  142  of the type disclosed in the &#39;573 patent are likewise keyed having an elongated configuration, so that insertion of the keyed ends  29  of the rotatable feet  16  into the truck bed receptacles  142  is facilitated only when the locking handles are rotated outwardly in the position depicted in  FIG. 3 . Thereafter, rotation of the locking handles 90° results in an interference between the keyed ends  29  and the elongated configuration of the receptacles  142 , preventing removal of the adaptor assembly  10  from the pickup truck bed. The locking handles are further provided with locking handle extensions  40  in which are provided locking holes  41 . When rotated to their locked position, the locking holes  41  of the two locking handles  32  are superimposed, and the locking handle extensions  40  are inserted into a locking slot  43  on the side reinforcing rails  20 . As the locking holes  41  of the two locking handle extensions  40  are superimposed and pass through the reinforcing rails  18 , a pin  42  is placed in the locking holes  41 , thereby restricting the locking handles  32  from rotation, and completing the process of locking the invention in place on the pickup truck bed. 
     Once the adaptor assembly  10  is secured in position, it will be readily understood that a conventional fifth wheel assembly  100  having mounting lugs  130  may be placed into the rectangular receptacles  22  of the mounting rails  20 , and secured in position with removable fasteners  132 . It will be likewise appreciated that when the fifth wheel assembly  100  is not in use, that it may be readily removed from the adaptor assembly  10  by removal of the removable fasteners  132  from the mounting rails  20 . Likewise, removal of pin  42  from the holes  41  in the locking handle extension  40  allows the locking handles  32  to be rotated thereby aligning the keyed ends  29  of the feet  16  with the receptacles  142  of the pickup truck bed, thereby allowing removal of the entire adaptor assembly  10  and leaving the pickup truck bed unimpeded by mounting rails. 
     It will also be appreciated that the fifth wheel assembly  100  can remain attached to the adaptor assembly  10  by keeping the removable fasteners  132  engaged with the mounting rails  20  of the adaptor assembly  10  and the mounting lugs  130  of the fifth wheel assembly. In this fashion, the combination of the fifth wheel assembly  100  and adaptor assembly  10  can be handled, installed, removed and stored as a unit, if desired. 
     The invention, accordingly, allows use of existing fifth wheel assemblies as designed for mounting in a first configuration on a towing vehicle, to be adapted for mounting on a towing vehicle having a second configuration for fifth wheel mounting. The above embodiment is but one example of an adaptor as contemplated by the present invention. 
     Having thus described my invention, numerous obvious modifications and improvements thereto may be made by the skill of the artisan, without departing from the substance of my invention, which I claim as follows: