Abstract:
A system for providing support to an articulating trailer hitch used to interconnect a trailer and a towing vehicle. The system includes an adjustable, removable and repositionable link which interconnects the trailer frame and one or more spring bars providing load-distributing forces to the trailer and towing vehicle. The spring bars include an adjustable, rigid link which maintains the vertical position of the hitch assembly when disconnected from the towing vehicle.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention pertains to load leveling trailer hitches, and more particularly, to a device and method for confining the movement of elements of a load-leveling trailer hitch. 
       BACKGROUND 
       [0002]    Mechanisms for interconnecting a motor vehicle to a trailer have been utilized extensively. Typically, a ball-type hitch is attached to the frame or bumper of a towing vehicle and a corresponding ball-type socket is secured to the trailer frame. The ball-type socket engages the hitch ball so described, and a locking mechanism secures the ball and ball socket together, while still allowing the ball and socket to rotate in relation to one another, thereby allowing the towed vehicle to articulate in relation to the towing vehicle in at least two axes. With relatively lightweight trailers, the afore described system results in a towed/towing vehicle combination which is useful, simple and safe to operate. 
         [0003]    However, modern towing vehicles and trailers, operating at highway speeds, often present interesting and difficult vehicle handling problems. Depending on the centers of gravity and centers of aerodynamic pressure associated with the towing and towed vehicles, towed vehicles exhibit a tendency to oscillate or wonder, a tendency which can be dangerous at high speeds. Further, vehicle operators typically increasingly demand more load-carrying capability from both towing vehicles and towed vehicles, resulting in much heavier vehicle weights, which in turn impose substantially higher mechanical loads on the vehicles. Because of these increased demands, more specialized, load leveling trailer hitch mechanisms have been developed which serve to more evenly distribute the tongue weight of the trailer over the front and rear axles of the towing vehicle. Further, it has been discovered that converging link configurations for trailer hitches can dramatically improve vehicle and trailer handling at highway speeds, such as those taught in U.S. Pat. Nos. 6,851,696 and 4,811,967. 
         [0004]    While load distributing and converging link trailer hitch systems have gained in popularity over recent years, they suffer from certain limitations. First, load distributing and converging link hitch systems are heavy, making it inconvenient to remove components of the towing system from both the towing and the towed vehicles. Further, the systems are complex, requiring the addition of components to or modifications to the trailer tongue or frame. Additionally, because the trailer-towing system is exposed to the weather and to the conditions found on the roadway, the mechanical components of the system become soiled, and it is undesirable to be required to disassemble and reassemble the various components of the system when it is desired to put the system to use. 
         [0005]    For these reasons, it is generally preferable to utilize a single receiver assembly attached to or integral with the towing vehicle which can be readily adapted to engage the elements on the tongue of the trailer. Typically, such a receiver is in the form of a rectangular cross-section socket, into which fits a corresponding rectangular cross-sectioned plug, which will be secured to the socket utilizing a bolt and nut, or a pin. In this configuration, almost the entire trailer hitch assembly remains associated with the trailer when the towing vehicle is disconnected. 
         [0006]    Unfortunately, such a configuration may allow the forward part of the trailer hitch to sag or droop, making it difficult to align with and reattach to the socket in the towing vehicle. This is particularly true where the spring bar portions of the trailer hitch assembly are secured at their proximal end to the converging link assembly and that their distal end to chains which are suspended from the trailer frame. When spring tension is removed from the spring bars of the trailer hitch, the spring bars are free to swivel, and provide no support to the converging link portion of the trailer hitch. 
         [0007]    It has been known to solve this problem by the incorporation of rigid jack elements which attach the distal end of the spring bar to the trailer frame. This allows the tension on the spring bars to be selectively relaxed, and further allows for precise positioning of the distal end of the spring bar in relation to the trailer frame. Unfortunately, this solution is incomplete, particularly when adapted for use on trailers having a so-called V-nose. V-nose trailers have a somewhat arrow-shaped cross-section which serves to streamline the trailer and make the trailer towing operation more fuel-efficient. Current jack systems of the type described protrude into the V-shaped frame of these trailers, creating the potential for interference between the front of the trailer compartment and the jacks. 
         [0008]    The present invention overcomes these limitations as will be further described herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0010]      FIG. 1  is a perspective view of the prior art in relation to a load leveling, converging link trailer hitch system. 
           [0011]      FIG. 2  is a perspective view of elements of the system configured at the distal end of the load leveling spring bars. 
           [0012]      FIG. 3  is a perspective view of the securement link portion of the system 
           [0013]      FIG. 4  is a perspective view of the forward portion of the trailer hitch assembly, including the converging link component. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    The following detailed description illustrates the structure and operation of the invention, which will be best understood by reference to the following disclosure, as well as  FIGS. 1-4 . 
         [0015]    A conventional trailer is provided with a metal frame which forms the underlying support for the towed vehicle, including the attachment points for the trailer axles on which the frame rests. The trailer frame supports a bed or an enclosure in which cargo may be carried. The forward end of the trailer includes a frame extension, sometimes referred to as a “tongue”. The trailer tongue is typically equipped with the necessary mechanism for securing the trailer to the towing vehicle. 
         [0016]    As previously described, the towing vehicle is conventionally equipped with a receiver, usually in the form of a socket. A ball-type hitch attached to a plug is inserted into the socket, and the plug and socket are secured together using a pin, nut and bolt, or other well-known means. Once this operation has been completed, the trailer hitch ball is rigidly secured to the receiver, which, in turn, is conventionally welded or bolted to the frame of the towing vehicle. 
         [0017]    The frame of the trailer is of generally box-shaped construction, and affixed thereto is a bracket, utilizing U-bolts. The bracket supports a lever assembly consisting of a pair of tangs pivotally attached to a lever element. 
         [0018]    At the forward end of the trailer, a hitch assembly comprised of a hitch bar is coupled to a hitch box enclosing a pair of links which are pivotally secured to the upper and lower portions of the hitch box. The converging link elements of the hitch box create the effect of moving the hitch point close to the rear axle of the towing vehicle, and hence, the towing vehicle steering input does not exaggerate the trailer&#39;s lateral movement. One or more struts may be added to the linkage to dampen movement, and to prevent the trailer hitch from rotating around the ball. All pivoting takes place in the linkage within a converging link unit, not at the hitch ball. 
         [0019]    When the hitch bar is withdrawn from the receiver on the vehicle, natural weight of the assembly causes it to sag or droop. 
         [0020]    One method of preventing this occurrence is the use of an adjustable jack as shown in  FIG. 1 . In this configuration, a bracket  20  is attached to the trailer frame  22  using U-bolts  24 . The upper end of a jack  26  is attached to a bracket, and the lower end of the jack  28  is attached to the distal end of the spring bar  30 . The proximal end of the spring bar  30  is secured into the forward part of the hitch assembly (not shown). Tension on the spring bar  30  may be adjusted by adjustment of the jack  26 . By virtue of the rigid interconnection of the trailer frame  22 , bracket  20  and jack  26 , the distal end of the spring bar  30  is held in a fixed position in relation to the trailer frame  22 , and the spring bar  30  provides vertical support to the converging link trailer hitch assembly (not shown), holding the assembly in relatively fixed position, which allows the vehicle and trailer to be easily interconnected. However, as can be seen from  FIG. 1 , the upper portion of the jack  26  presents an obstacle to portions of the trailer body which may project forward from the trailer frame. 
         [0021]      FIG. 2  shows an embodiment of the present invention, including a modified bracket  40  which contains a U-shaped support flange  42 , a pair of tangs  44 ,  46 , a pivot lever  48  and chain  50 , and an adjustable, rigid link  52 . 
         [0022]    The modified bracket  40  is mounted securely to the trailer frame  54  utilizing U-bolts  56 . The support flange  42  accepts a pin  58  which engages a brace  60 . The brace  60  restricts rotations of portion of the hitch assembly (not shown). The modified bracket  40  also incorporates a tensioner comprising a pair of tangs  44 ,  46  fitted with pivots  48 , which engage a lever  64  provided with a plug  66 , a hook  70  and an eye  68 . When the trailer is configured for towing, a chain  50  interconnects the distal end  76  of the spring bar  72  and the hook  70  mounted to the lever  64 . The lever  64  is then rotated upward about the pivots  48 , until the eye  68  of the lever  64  engages a slot  74  mounted on a third tang  6  on the bracket  40 . A pin or other securing element (not shown) can be placed through the eye  68 , preventing the lever  64  from rotating. In this configuration, tension is applied to the chain  50 , which in turn supplies tension to the spring bar distal end  76 , thereby applying the necessary load leveling forces to the trailer hitch assembly (not shown), achieving the desired result of dispersing the trailer weight loads evenly between the axles of the towing vehicle. 
         [0023]    When it is desired to park the trailer and separate the trailer from the towing vehicle, the support system of the present invention incorporates an adjustable, rigid link  52  which is positioned between the support flange  42  and the distal end of the spring bar  76 . Prior to separating the towing vehicle and the trailer, the lever  64  is rotated downward as shown in  FIG. 2  about the pivots  48 , thereby releasing the tension on the spring bar  72 . The adjustable, rigid link  52  is provided with one or more holes and pins  78 . In this fashion, the overall length of the link  52  can be adjusted. The upper end of the link  52  is provided with an eye  80  through which a pin  82  is inserted, passing through openings in the support flange  42 , thereby securing the link  52  at its upper end, to the bracket  40  and support flanges  42 . At the opposite end of the link is a fork  84  which captures the distal end of the spring bar, and one or more holes  86  in the fork  84  accept a locking pin (not shown) which captures the underside of the distal end of the spring bar  76 , thereby providing vertical support to the spring bar  72  at its distal end  76 .  FIGS. 3 and 4  show additional views of embodiments of this invention.  FIG. 3  shows the spring bar  72 , the adjustable, rigid link  52  with a fork  84  with one or more holes  86 .  FIG. 4  shows the distal end  76  of the spring bar  72  operatively connected to the adjustable, rigid link  52  by the fork  84 . The adjustable, rigid link  52  is connected to the support flange  42  by a pin  82  inserted though an eye  80  attached to the link  52 . 
         [0024]    It will be appreciated that this combination of elements eliminates the requirement for a jack to raise and lower the distal end of the spring bar, thereby eliminating the potential for interference between the upper end of the jack and the body or load being carried on the trailer frame. Further, this configuration provides the necessary support for the converging link trailer hitch assembly in that the supporting link holds the distal end of the spring bar in position, so that the towing vehicle may be removed without allowing the converging link and load leveling trailer hitch assembly to sag or otherwise become misaligned. 
         [0025]    When it is time to interconnect the vehicles again, the trailer hitch assembly is already in position for interconnection. Once the converging link/load leveling portion of the hitch has been reattached to the towing vehicle socket, the link assembly can be removed from its position interconnecting the support bracket and the distal end of the spring bar, and tension can be reapplied to the lever, thereby providing tension to the chain and to the spring bar itself, thereby applying the necessary load to the spring bar. 
         [0026]    Having thus described my invention, numerous obvious modifications and improvements thereto may be made by the skill of artisan, without departing from the substance of my invention, which I claim as follows: