Abstract:
A load leveling weight distributing hitch which provides enhanced flexibility of attachment and removal is described. This invention is directed to load leveling weight distribution hitches with enhanced strength and which are easy to install and adjust, without the use of special tools or equipment. This invention addresses the attachment of the spring bars commonly used with load leveling hitches by presenting a quick connect/quick disconnect which permits the user to easily install the spring bars without the use of special tools. Additionally, this invention provides a thumb screw adjustment for modifying the pitch angle of the ball hitch. This invention also provides a spring bar lift which provides a novel locking mechanism as well as a chain retention device for maintaining the chain tension during sway.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to hitch systems for trailers. More specifically, this invention relates to hitch systems for ball-type couplers, which provide for load leveling, weight distribution, tilt angle ball adjustment, a new and improved means for installing and removing the spring bar components of the invention as well as a new and improved device for lifting and securing the spring bar components of the invention. 
     2. Description of the Related Art 
     A variety of hitch assemblies for evenly distributing the tongue weight of a trailer are well known in the art. Commonly such hitch assemblies include a hitch head, spring bars, bar restraining sockets, and lift units. The head provides the ball mount, the towing vehicle attachment and spring bar attachments. Typical such hitch assemblies use substantially L-shaped spring bars, or use substantially rectangular sockets. Also, if ball pivot adjustment is provided, it requires that the user unbolt, remove and relocate the hitch head. Such existing load leveling or weight distributing hitches are generally mechanically complex with a large number of bolt and nut attachment to fix the hitch together. Mechanical complexity has the disadvantage of being generally less reliable. Also, a disadvantage of the prior weight distributing hitches is that it is relatively difficult for the user to attach the spring bars to the hitch head or for the user to remove the spring bars from the hitch head. This problem makes it significantly more difficult for the user to attach a trailer to a towing vehicle using load leveling hitches. Prior load leveling hitches provide limited or no tension adjustment capability. 
     For general background material, the reader is directed to U.S. Pat. Nos. 3,645,560, 3,649,046, 3,679,231, 3,690,699, 3,692,331, 3,700,261, 3,700,262, 3,730,554, 3,731,746, 3,731,950, 3,778,088, 3,779,407, 3,825,132, 3,847,228, 3,871,686, 3,910,604, 3,964,768, 3,948,567, 3,989,269, 4,023,863, 4,025,085, 4,049,288, 4,053,174, 4,165,885, 4,198,073, 4,211,427, 4,213,627, 4,275,897, 4,312,516, 4,411,444, 4,637,770, 4,687,219, 4,711,106, 4,714,265, 4,722,542, 4,815,752, 5,184,839, 5,284,038, 5,363,924, 5,375,867, 5,421,599, 5,451,088, 5,454,550, 5,465,991, 5,489,111, 5,536,131, 5,562,298, 5,575,492, 5,580,076, 5,615,813, 5,628,525, 5,647,603, each of which is hereby incorporated by reference in its entirety for the material disclosed therein. 
     SUMMARY OF THE INVENTION 
     It is desirable to provide a load leveling weight distributing hitch system for use in towing trailers where the attachment and removal of the spring bars is facilitated and can be accomplished by hand. Moreover, it is desirable to provide a load leveling weight distributing hitch system which provides the capability of spring bar tension adjustment. It is also desirable to provide a load leveling weight distributing hitch system which provides a thumb screw adjustment of the ball hitch pitch. 
     Accordingly, it is an object of this invention to provide a load leveling weight distributing hitch system which provides a quick connect, quick disconnect for the spring bars. 
     It is another object of this invention to provide a load leveling weight distributing hitch system which provides the capability of adjusting the tension of the spring bars. 
     A further object of this invention is to provide a load leveling weight distributing hitch system which provides a thumb screw adjustment for the pitch of the ball hitch. 
     It is a still further object of this invention to provide a load leveling weight distributing hitch system with enhanced strength. 
     Another object of this invention is to provide a load leveling weight distributing hitch system with enhanced reliability by minimizing the use of attachment bolts. 
    
    
     These and other objects of this invention, which are readily apparent to those of ordinary skill in the art upon review of the following specification, drawings and claims, are achieved by a device which is described in the specific embodiment of this invention. Specifically, a hitch head is provided with a ball hitch attachment point, a towing vehicle attachment, two T-socket posts, two T-sockets, two spring bars having attachment points for stabilizer chains, and two lift units for imposing tension on the spring bars. Innovations in this design include a quick connect/disconnect for the spring bars, a tension adjustment system, and a thumb screw device for adjusting the pitch of the ball hitch. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a system drawing showing two view of the load leveling weight distributing hitch system being used to connect a towing vehicle to a trailer. 
     FIG. 2 is a detail drawing showing five views of the preferred embodiment of the hitch head component of the invention. 
     FIG. 3 is a detail drawing showing three views of the preferred embodiment of the post component of the invention. 
     FIG. 4 is a detail drawing showing two views of the preferred embodiment of the T-socket component of the invention. 
     FIG. 5 is a detail drawing showing two views of the preferred embodiment of the spring bar component of the invention. 
     FIG. 6 is a detail drawing showing three views of the preferred embodiment of the spring bar lift component of the invention. 
     FIG. 7 is a detail drawing showing two views of the preferred embodiment of the spring bar lift lock component of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     This invention is a load leveling weight distribution hitch which uses a quick connect, quick disconnect spring bar attachment, a thumb screw ball hitch pitch adjustment, a spring bar lift having the ability to adjust the tension imposed on the spring bar, and spring bar lift lock, to provide a new hitch design which provides enhanced strength, reliability, ease of use and adjustments over weight distributing hitches in prior use. 
     FIG. 1 a  and  1   b  depict the load leveling and weight distributing system showing the hitch being used to connect a towing vehicle to a trailer. FIG. 1 a  is a view from above the system of the invention. FIG. 1 b  is a side view showing the left side of the invention. The towing vehicle  105  has a standard hitch receiver  106  which is attached to an adjustable shank  110  which is fixed by bolts  112 ,  113  to the hitch head  101  of the invention, which in turn has two “T” sockets  102   a ,  102   b . Each “T” socket  102   a ,  102   b  is shown having received the spring bars  103   a ,  103   b . Each spring bar  103   a ,  103   b  has a chain  111  attached to its trailer end  114 . The chain  111  is provided to control trailer sway. The chain  111  is connected to the trailer tongue  107  via a spring bar lift  104   a ,  104   b . The spring bar lift  104   a ,  104   b , has a sway control bracket  115  which is provided to keep the chain  111  fixed in place, thereby controlling the trailer sway. The trailer tongue  107  is connect to the hitch head  101  by a standard ball  108  and socket  109  connection. In the preferred embodiment of the invention, the component parts of the invention are composed of steel, although alternative materials, including synthetics may be used without departing from the concept of the invention. 
     FIGS. 2 a ,  2   b ,  2   c ,  2   d , and  2   e  show the detail drawing of five view of the preferred embodiment of the hitch head  101  component of the invention. FIG. 2 a  shows a top down view of the hitch head  101 . FIG. 2 b  shows a section view along the line A—A of the hitch head  101 . FIG. 2 c  shows the side view of the hitch head  101 . FIG. 2 d  shows the rear view of the hitch head  101 . And FIG. 2 e  shows the front view of the hitch head  101 . The preferred hitch head  101  has a top surface  204  in which three openings are provided, a ball hitch attachment opening  202 , which receives the ball stem  116 , two T-socket post holes  201   a,b , two shank mount plates  203   a ,  203   b , each of which has two bolt openings  208 ,  209  for fixing the hitch head  101  to the adjustable shank  110 . It can be seen that the top bolt opening  208  is provided as a slot which provides the user/installer with the capability of adjusting the pitch of the hitch head  101 . Ball hitch  108  adjustment is provided by a thumb screw  206  having a drive end and a thumb head end which is installed through a threaded opening  209  and which by being turned by the user/installer the relative pitch of the ball can be adjusted. This ball hitch  108  adjustment is presently preferably accomplished by turning the thumb head end  213  of the thumb screw  206  thereby pressing the drive end  212   a  of the thumb screw  206  against to interact with the bolt opening  208  in order to provide adjustment to the pitch of the hitch head  101 . In one preferred embodiment of this invention, a sway control adjustment plate  210  is provided, fixed to the bottom of the hitch head  101  by bolts  215  provided through bolt openings  212  and fixed to the bottoms of the T-socket posts by bolts  214  provided through bolt openings  211 . A variety of hitch head sizes can be employed depending on the ball hitch, trailer tongue and desired spring bar pitch and tension, without departing from the concept of this invention. 
     FIGS. 3 a ,  3   b ,  3   c  and  3   d  are detail drawings of the preferred embodiment of the post component of the invention. FIG. 3 a  shows a side view of the T-socket post  301 , showing the T-socket rotation slot  302 , which is a slot cut into the periphery of the T-socket post  301  and extending generally half way around the T-socket post  301 , to provide an engagement with a T-socket pin  409 , which is installed through a pin opening  403  in the T-socket  102 , to allow the T-socket  102  to pivot approximately 180 degrees about the t-socket post  301 . FIG. 3 b  shows the top down view of the preferred T-socket post  301 . FIG. 3 c  shows a section view of the post  301  along the A—A section. FIG. 3 d  shows a side view of the T-socket post  301  which shows the T-socket installation slot  304 . The post  301  is provided with a tapered end  305  which is press fitted into the post opening  201  of the hitch head  101 . Once press fitted in, the post  301  is welded securely into place. A bolt hole opening  303  is provided in the event the sway control plate  210  is used. When installed each T-socket  102  is provided with a pin which passes through an opening in the T-socket to the T-socket rotation slot  302 . This combination of the T-socket pin and the T-socket rotation slot provides the capability of rotating the spring bars  103  away from the trailer, thereby aiding in the installation and removal of the spring bars  103 . The T-socket installation slot  304  is provided in order to allow the T-socket  102  to be installed on the post  301 . Preferably, the post  301  is made from polished high strength steel. Alternative materials could be used without departing from the scope of this invention. 
     FIGS. 4 a  and  4   b  provide detail drawings showing two views of the preferred embodiment of the T-socket  102  component of the invention. FIG. 4 a  shows a top down view of the T-socket  102 , while FIG. 4 b  shows a section view along the A—A line. A tube opening  401  is provided, which is installed over the post  301 . A spring bar opening  402  is provided to receive the first end of the preferred spring bar  103 . The pin opening  403  is provided to interact with the T-socket pin  409  and the T-socket rotation slot  302  to permit the t-socket  102  to rotate about the post  301 . A set screw opening  404  is provide to fix the T-socket pin  409  in place. Also, provided in the T-socket is a retainer pin opening  405 . The use of a retainer pin  406  which is held in place by a spring  408  pinned  407  to the T-socket, provides the quick connect/quick disconnect feature of this invention. This is accomplished in combination with the retainer pin slot  502  of the spring bar  103 . When the spring bar  103  is installed in the T-socket  102  it is pushed straight in forcing the retainer pin  406  up and then down into the retainer pin slot  502 . The retainer pin  406  being sprung to allow movement only on the insert of the spring bar  103  fixes the spring bar  103  in the T-socket. To remove the spring bar  103 , it is rotated in either direction. Rotation of the spring bar  103  causes the retainer pin slot  502  to force the retaining pin  406  upwards, thereby releasing the spring bar  103 . In the preferred embodiment of the invention the T-socket is pitched downward to induce tension in the spring bar  103 . The preferred T-socket is composed of cast steel, although alternative materials could also be used without departing from the scope of this invention. 
     FIGS. 5 a  and  5   b  provide detailed drawing of the preferred embodiment of the spring bar component  103  of the invention. FIG. 5 a  show the top down view of the preferred embodiment of the spring bar component  103  of the invention. FIG. 5 b  shows the side view of the spring bar  103 . The retainer pin slot  502  is shown for use as described above. A taper  505  is provided on the first end  501  of the spring bar  103 . This taper  505  provides the means whereby the retainer pin  406  is forced upwards, allowing the spring bar  103  to be inserted and locked in place within the T-socket  102 . The second end  503  of the spring bar  103  has two holes  504   a ,  504   b  which provide an access for attaching a tension chain  111 . In the preferred embodiment of the invention, the spring bar  103  is made of steel, although alternative materials could be used without departing from the concept of this invention. 
     FIG. 6 is a detail drawing showing three views of the preferred embodiment of the spring bar lift component of the invention. FIG. 6 a  shows a top down view. FIG. 6 b  shows a front view and FIG. 6 c  shows a side view. The spring bar lift  104  is an improved version of commonly known spring bar lift type devices. The purpose is to receive one or more chain links into the opening  601  and then to leverage the lift upwards, by inserting a bar or other equivalent means, into the concave opening in the chain latch  606  to thereby lock the chain to the lift in a fixed position. Two important improvements to previously known spring bar lifts are provided in this invention. First, a chain retention loop  602  which is a generally oval loop, fastened typically by a weld, although other fastening means could be employed in alternative embodiments, to the inverted U-shaped element  605 , within which chain  111  can be inserted to reduce chain  111  movement, is provided to maintain chain tension in a sway. Second, an improved lift lock  603  is provided. Additional detail on the improved lift lock  603  is provided below. Other features of the spring bar lift  104  include: a clamp devices  604  for fixing the lift  104  to the trailer tongue  107 ; an inverted U-shaped element  605  adapted to fit over the trailer tongue  107 ; and a pivotable chain latch  606  which pivots about a pivot point  607 . The preferred pivotable chain latch  606  is a three piece structure having two side portions  609   a ,  609   b  and a center portion  610 , the center portion  610  having within it the chain opening  601  and each side portion  609   a ,  609   b  being attached to a brace member  608   a ,  608   b  by a pivot point  607 . The preferred pivotable chain latch  606  is a three piece structure having two side portions  609   a ,  609   b  and a center portion  610 , the center portion  610  having within it the chain opening  601  and each side portion  609   a ,  609   b  being attached to a brace member  608   a ,  608   b  by a pivot point  607 . 
     FIGS. 7 a  and  7   b  are detail drawings of the preferred embodiment of the lift lock component  603  of the invention. FIG. 7 a  is a side view and FIG. 7 b  is a section view cut along the A—A axis. The preferred embodiment of the lift lock has an exterior body  701  within which is installed a pivot pin  703  which in turn is held in a normally locked position by an internal spring  706  inserted within the exterior body  701 , with one end  708  of the spring  706  against an interior wall  709  on tapered end  705  of the lift lock  603 , and the other end  710  of spring against a piston  707  by pressure imposed on a piston  707  affixed to the locking post  702 . In the normally locked position, the locking post end  702  engages an opening  608  in the pivotable chain latch  606 . However, when the post  704  is rotated by the user along the tapered section  705  of the body  701  of the lift lock  603 , the locking post  702  is withdrawn from the opening  608 , thereby releasing the pivotable chain latch  606 , and relaxing the tension on the chain. 
     The described embodiments of the invention are to be considered in all respects as illustrative only and not as restrictive. Although the embodiments shown here describe materials and specific interrelationships, these are to be considered only as descriptive of the current best mode of the invention as known to the inventors at the time the patent application is filed. The scope of this invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and equivalency of the claims are to be embraced within their scope.