Abstract:
Described herein is a trailer hitch adapter designed to relieve the weight of a trailer from applying directly onto the hitch of a towing vehicle. The hitch adapter features a towing bar pivotally secured to a frame with a wheel base, the towing bar resists pivotal movement by spring and damper assemblies. The frame has a hitch for receiving the trailer and the towing bar has a hitch for attachment to the towing vehicle. The wheel base of the hitch adapter is movable between a forward and rearward position.

Description:
BACKGROUND OF THE INVENTION 
     The use of campers and other recreational vehicles which are towed behind a pick-up truck or other light-duty vehicle have increased dramatically over the years. The number of families who abandon traditional tents in favor of large campers has driven trailer manufacturers to increase the size and features available. With increased features and increased size comes an increase in the weight of the trailer. 
     However, while heavier trailers have become more popular, heavier hitches to haul the trailers have not. The average trailer hitch is able to support roughly one tenth its towing weight in vertical load. For example, a hitch which is able to tow 6,000 pounds of weight will only support 600 pounds of vertical load. Therefore, as can be shown, in order to pull the full supported 6,000 pounds of weight, the load must be virtually evenly distributed about the axle of the trailer. Most trailers are not designed with the axle centered on the trailer and most users of trailers do not consider this limitation in their towing vehicle when loading the trailer. 
     Because of overloading of trailers and unequal load distribution in the trailer itself, it is common for trailer hitches to suffer from increased wear and premature failure if subjected to regular overloading. It has therefore been recognized in the art that there is a need for a trailer hitch support apparatus which compensates for additional weight on a trailer. Several apparatus have been proposed which compensate for this increased weight, but each suffers from similar shortfalls. 
     One type of hitch adapter that is widely available is the “Hell Ya Hitch Helper” which features a square hitch coupler, spring suspension, and tires mounted to an axle. Another hitch adapter that is available is the invention described in U.S. Pat. No. 6,820,887. This device features a trailer adapter mounted to a pivoting axle, thereby allowing the axle of the device to turn with the vehicle. However, both of these hitch adapters are unable to be easily used in reverse, causing “scrubbing” of the tires, which results in uneven and excessive wear on the tires. 
     Therefore, it is the primary objective of the invention to provide a trailer hitch adapter which is able to support the weight of the trailer without damaging the hitch of the tow vehicle by eliminating the down forces of the trailer tongue weight, hence keeping the tow vehicle aligned to the road as before the trailer would be attached to tow vehicle. 
     It is a further objective of the invention to provide a trailer hitch adapter which will turn and follow the tow vehicle in both forward and reversing directions and prevent the hitch adapter from turning in an opposite or stationary position which in turn causes premature tire wear and damages. 
     It is also the objective of the invention to provide safe towing practices by allowing this hitch adapter to absorb the up and down movement of the trailer tongue weight and sideways swaying which will dramatically reduce the unstable forces to the towing vehicle and frame structure of the vehicle. 
     SUMMARY OF THE INVENTION 
     The following description generally describes a hitch adapter for use between a towing vehicle and a trailer. The hitch adapter has a forward and a rear hitch for engaging the towing vehicle and trailer, respectively. The forward hitch extends from the adapter on a towing bar. The rear hitch and towing bar are mounted to a first frame member. A set of wheels are mounted to a second frame member which may slide relative to the first frame member. 
     According to an alternative embodiment, the hitch adapter has a first hitch on a towing bar, the towing bar and a second hitch secured to a frame. The towing bar is secured to the frame so as to pivot about the frame. A shock assembly for resisting movement of the towing bar relative to the frame connects the towing bar to the frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an elevated side view of a trailer mounted to a vehicle. 
         FIG. 1B  is an elevated side view of a trailer mounted to an adapter, the adapter mounted to the vehicle. 
         FIG. 2  is an enlarged elevated side view of the adapter shown in  FIG. 1B . 
         FIG. 3A  is an elevated side view of the adapter with the vehicle removed and the adapter in a towing position. 
         FIG. 3B  is an elevated side view of the adapter with the vehicle removed and the adapter shown in a towing position with dashed lines indicating the adapter in a reverse position. 
         FIG. 3C  is an elevated side view of the adapter with the vehicle removed and the adapter shown in a reverse position. 
         FIG. 4  is an elevated rear view of the adapter with the trailer removed. 
         FIG. 5  is an enlarged perspective view of the underside of the adapter. 
         FIG. 6  is a view of the underside of the adapter with the actuator in an extended position. 
         FIG. 7  is a view of the underside of the adapter with the actuator in a retracted position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description generally describes a hitch adapter for use between the tow vehicle and a trailer. 
     The top towing bar  20  has an adjustable slide plate for vertical alignment of the hitch adapter  10  which in turn slides into the towing vehicle&#39;s  12  hitch receiver  36 . The adjustable slide plate has a plurality of slots for receiving a fastener. 
     The adjustable slide plate then attaches to a pivoting assembly  26  which has circular fastener holes corresponding to the plurality of slots on the adjustable slide plate. The combination of slots and through holes allows the pivoting assembly  26  to be vertically adjusted relative to the adjustable slide plate. The pivoting assembly  26  compensates for up and down movement on uneven surfaces. 
     The towing bar  20  assembles into the pivoting assembly  26 . The opposite end of the towing bar  20  serves as the receiver for the trailer&#39;s hitch ball unit  28 . The towing bar  20  is preferably manufactured of a square steel tube to receive the hitch ball unit  28 , although other arrangements are anticipated. 
     The towing bar  20  has mounts for the middle frame positioning tensioners  40 . The towing bar may also have two mounts for optional triangulation bars (not shown) mounting to the tow bar  20  for stabilization of the tow bar  20 . A pivoting spindle is located by the trailer&#39;s hitch ball  28  assembly end to connect to the top frame assembly  46 . 
     The top frame assembly  46  (the top frame may also be known as the more generic first frame) is located below the towing bar  20  and attached to the towing bar  20  through the towing bar spindle and top frame assembly spindle/hub assembly  21  through means known in the art. 
     The top frame assembly  46  has a connection point for the positioning tension to the towing bar allowing the top frame assembly  46  and bottom frame assembly  48  (also called a second frame in a more generic sense) to pivot together for wheel direction of the hitch adapter while allowing the towing bar  20  to remain straight between the tow vehicle and trailer. The position tensioners  40  maintain the hitch adapter  10  in stable motion and turning with the tow vehicle  12 . 
     The top frame assembly  46  incorporates a roller assembly  60  to the lower frame  48 . This roller assembly  60  allows the lower frame wheel assembly movement forward and reverse to allow the changing of the tow bar/middle frame pivot point to either in front of or behind the wheel axle  56  thus allowing the adapter  10  to track the proper directions as controlled by the towing vehicle  12 . When the pivot point is in front of the axle  56 , forward motion; when the pivot point is behind the axle  56 , reverse motion. 
     The top frame assembly  46  has a movement/sliding drive device  54  attached to itself for automatic positioning to the lower frame assembly  48 , but will also function without said drive device for manual positioning of movement direction. The sliding drive device  54  is preferably a hydraulic or pneumatic piston, although other arrangements are anticipated. 
     The bottom frame assembly  48  incorporates the hitch adapter&#39;s wheels  16 , tires, axle  56 , load bearing leaf springs  52 , dampening shocks, and support structure for movement/sliding drive device  54  attached to the top frame assembly  46  for forward or reverse positioning. 
       FIG. 1A  shows the conventional method of connecting a trailer to a vehicle. A trailer hitch on the towing vehicle  12  receives the trailer. As explained in the background of the invention, this provides extra weight onto the hitch and vehicle suspension. 
     As generally shown in  FIG. 1B , the adapter  10  is designed to be placed between a towing vehicle  12  and a trailer  14  to relieve the load on the towing vehicle. The adapter  10  generally consists of a set of wheels  16 , a frame  18 , and a towing bar  20  extending from the front  22  of the adapter. The towing bar  20  has at its forward end a square hitch  26  and at its rearward end is adapted to receive a ball hitch  28 . The forward square hitch  26  is attached to the towing vehicle  12  and the rearward ball hitch  28  is attached to the trailer. 
     As shown in  FIG. 2 , the towing bar  20  is pivotally attached to the frame  18  at a point near the rearward end. At the forward end of the towing bar  20  is a forward hitch assembly  26  which engages with the towing vehicle  12 . 
     The forward hitch assembly  26  consists of a square hitch insert  30  and a kingpin assembly  32  which engages the towing bar  20  of the adapter  10 . The kingpin assembly  32  pivotally supports the towing bar  20  so that the adapter  10  can move vertically relative to the towing vehicle  12  without being disconnected. The kingpin assembly allows for the adapter  10  to move vertically relative to the towing vehicle  12  when travelling over uneven ground. This stops the hitch on the towing vehicle  12  from bearing the full weight of the trailer  14  and adapter  12 . The square hitch insert  30  is generally an elongated tube of a square cross section with a hole  34  perpendicular to the axis. This hole  34  receives a pin (not shown) which locks the hitch insert  30  to the hitch  36  on the towing vehicle  12  and prevents the hitch  30  from being disengaged from the towing vehicle  12 . 
     The towing bar is preferably made of a square tube steel, allowing a ball hitch  28  to be inserted into the rearward end of the towing bar  20 . The towing bar  20  is pivotally connected to the frame  18  near the rearward end. The towing bar  20  features an extension  38  passing through the frame  18 . The towing bar  20  is allowed to pivot about the frame  18 , thereby allowing the frame  18  to turn separately from the towing vehicle  12 . Also between the frame  18  and towing bar  20  are a pair of spring  42  and damper  44  shocks  40  which resist movement of the towing bar  20 . These shocks prevent “jack-knifing” of the hitch adapter  10  when the towing vehicle  12  is turned while in reverse by guiding the wheels  16  of the adapter  10  to track with those of the towing vehicle  12 . These shocks  40  also prevent the trailer  14  from fishtailing due to the presence of two pivot points (between the towing bar  20  and frame  18  and between the rear hitch  28  and trailer  14 ) by providing resistance against pivoting. 
     The frame  18  consists of two parts, a top frame assembly  46  and a bottom frame assembly  48 . The shocks  40  and towing bar  20  are mounted to the top frame assembly  46 . The wheel assembly  50  is mounted to the bottom frame assembly  48  and consists of springs  52 , an axle  56 , and the wheels  16 , although it should be understood that alternative methods of mounting wheels to a frame are known in the art. For example, traditional damper shocks may be utilized, or the wheels may be mounted to separate axles, or several wheel sets may be used. 
     The top  46  and bottom  48  frame assemblies are connected to one another by a sliding mechanism  60 . This sliding mechanism  60  allows movement of the wheels  16  relative to the pivot point between the towing bar  20  and frame  18 . As shown in  FIG. 5 , the sliding mechanism  60  is controlled to either a forward or a rearward position by a piston  56 . When the sliding mechanism is in the forward position the pivot point between the towing bar  20  and frame  18  is in front of the axle  56 , which is the preferred position for pushing the trailer  14 . When the sliding mechanism is in the rearward position the pivot point between the towing bar  20  and frame  18  is behind the axle  56 , which is the preferred position for towing the trailer  14 . 
     The sliding mechanism  60  is controlled to the forward or rearward position by means of a pneumatic or hydraulic piston  54 , as shown in  FIGS. 6 and 7 . This piston  54  is preferably operated by an electrical signal sent from the towing vehicle  12 . For example, because the trailer  14  is most maneuverable when being towed if the pivot point between the towing bar  20  and frame  18  is in front of the axle  56 , the default position of the piston  54  should be that which places the frame  18  in the rearward position. When the towing vehicle  12  is placed in reverse, the piston  54  should automatically adjust so that the frame  18  is placed in the forward position. 
       FIGS. 3A-3C  show the adapter being moved from a towing or forward position to a pushing or reverse position.  FIG. 3A  shows the adapter in a towing or forward position. In this position, the pivot point between the towing bar  20  and frame  18  is located behind the axle  56 . When the towing vehicle is placed in a reverse gear, this fact is communicated to the adapter which moves the axle  56  or bottom frame assembly  48  to the reverse or pushing position. 
       FIG. 3B  shows the adapter in the towing or forward position with the pushing or reverse position shown in dashed lines. Once the towing vehicle  12  is placed in a reverse gear, the piston actuates and begins to move the wheel and axle assembly to the location indicated in dashed lines. As can be seen, the wheel and axle assembly comprises part of the frame, and as the assembly moves, the axle is placed forward of the pivot point between the towing bar  20  and frame  18 . 
       FIG. 3C  shows the adapter in the reverse or pushing position. As can be seen, the wheel and axle assembly has been moved forward while the trailer and both forward and rear hitches have remained stationary. It is not necessary for an operator to exit the vehicle in this process, the entire system functions automatically. 
     One method of this communication between the vehicle  12  and adapter  10  is through an electrical connection between the towing vehicle and adapter. When the towing vehicle is placed in a reverse gear, an electrical signal is sent through the connection to indicate that reverse lights should be lit in the adapter or towed vehicle. The adapter may utilize this signal to trigger an actuator or solenoid coupled to the piston  54  to move the adapter to the reverse or pushing position. 
     As shown in  FIG. 2 , additional connectors between the towing vehicle and adapter as well as between the adapter and trailer may be included. For example, chains are commonly used to provide a backup connection between the hitches, should the hitch fail. Additionally, electrical connectors, controlling the brake and tail lights, are commonly used. It is also anticipated that other arrangements may be used. 
     In one alternative arrangement, triangulation bars may be added between the towing vehicle  12  and adapter  10 . These triangulation bars generally consist of a rigid steel rod with rod ends secured to either end. The rod ends allow the steel rods to flex to some degree while traveling over the road, but provide additional support when backing up the vehicle  12  and adapter  10 . Rod ends are generally known in the art. They constitute a spherical bearing with a through hole, the spherical bearing located within a bushing. The bushing has a threaded rod extending away from the bushing. 
     A general description of the present invention as well as a preferred embodiment of the present invention has been set forth above. Those skilled in the art to which the present invention pertains will recognize and be able to practice additional variations in the methods and systems described which fall within the teachings of this invention. Accordingly, all such modifications and additions are deemed to be within the scope of the invention which is to be limited only by the claims appended hereto.