Abstract:
An interchangeable ball hitch includes a post with a threaded stem and a tapered shank, a ball including a tapered bore adapted for receipt on the tapered shank and a cap for engaging a locking track carried on the tapered shank and securing the ball to the post.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 60/117,544 filed Jan. 28, 1999 and is a continuation of U.S. patent application Ser. No. 09/479,152 filed Jan. 7, 2000. 
     
    
     
       TECHNICAL FIELD  
         [0002]    The present invention relates generally to the towing field and more particularly to an interchangeable ball hitch that may be conveniently utilized to quickly and efficiently tow trailers requiring hitch balls of various diameter.  
         BACKGROUND OF THE INVENTION  
         [0003]    The use of a ball joint coupling comprising a hitch ball and cooperating socket assembly in order to tow a trailer behind a towing vehicle is well known in the art. Such an arrangement provides the necessary freedom of movement to allow a trailer to track smoothly behind the towing vehicle and this is advantageously accomplished while also providing a dependable connection.  
           [0004]    Over the years hitch balls of various diameters have been used for this purpose and several industry standard sizes (e.g. 1 ⅞″, 2″, 2 ¼″, 2 {fraction (5/16)}″) are now in frequent use. As a result, it is not uncommon for a single towing vehicle to be used to tow various trailers where those trailers are equipped with socket assemblies adapted for operative connection with hitch balls of different diameters. Thus, a need is identified for a ball hitch allowing easy and convenient interchange of hitch balls of different diameter so that the hitch of the towing vehicle may be tailored to fit the socket assembly on the trailer to be towed and thereby meet application needs.  
           [0005]    Toward this end, a number of approaches have been proposed in the past. Representative of the interchangeable ball hitch art are U.S. Pat. Nos. 4,433,854 to Smith, 4,522,421 to Vance and 4,938,496 to Thomas et al. Generally, the prior art approaches are relatively complicated structures having many parts. As a consequence, they are not only expensive to produce but also suffer from an increased likelihood of failure. In addition, many require special tools in order to allow the hitch ball to be changed. If these tools are lost or misplaced, significant inconvenience results. Accordingly, it is apparent that a need exists for an improved interchangeable ball hitch overcoming the various limitations and disadvantages characteristic of the prior art.  
         SUMMARY OF THE INVENTION  
         [0006]    Accordingly, it is a primary object of the present invention to provide an interchangeable ball hitch of relatively simple and inexpensive yet durable construction providing convenient interchangeability of balls of various diameter over a long and dependable service life.  
           [0007]    An additional object of the present invention is providing an interchangeable ball hitch wherein balls of various diameter may be securely held on a cooperating post while allowing relative rotation between the ball and post for best possible towing performance and efficiency.  
           [0008]    Still another object of the present invention is providing an interchangeable ball hitch wherein the ball may be quickly and conveniently changed as required to meet the needs of the vehicle operator in towing trailers of various hitch arrangements without the need of special tools.  
           [0009]    Additional objects, advantages and other novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.  
           [0010]    To achieve the foregoing and other objects, and in accordance with the purposes of the present invention as described herein, an improved interchangeable ball hitch is provided. The interchangeable ball hitch includes a post having a mounting stem and a tapered shank. Preferably, the tapered shank carries a locking track and cavity.  
           [0011]    A ball including a tapered bore is received on the tapered shank. Additionally, a cap is provided for engaging the locking track and securing the ball to the post. A detent incorporating a spring loaded pin is received in the cavity for engaging the cap and securing the cap in place in its ball securing position.  
           [0012]    Still more specifically describing the invention, the mounting stem is threaded. The mounting stem is inserted through a cooperating opening in the tow bar or ball mount of the hitch and may be secured in place by means of an appropriate fastener of a type known in the art such as a locking nut.  
           [0013]    In addition, in the most preferred embodiment the cap includes a pair of opposed guide rails for engaging the locking track. Additionally, the cap includes a notch which receives the locking pin when the cap is properly seated on the locking track. This advantageously insures that the cap is positively held in the desired position for securing the ball to the post. Thus, a double lock of highest integrity is provided.  
           [0014]    In accordance with yet another aspect of the present invention, a method is provided for securing a hitch ball to a post. The method includes the steps of (1) placing the hitch ball on the post and (2) sliding a cap over the hitch ball. More specifically, one slides the cap in a direction substantially perpendicular to the longitudinal axis of the post until the cap engages the post and secures the hitch ball to the post. The method may be further defined as including the step of providing a track on the post for engagement with the cap.  
           [0015]    Still other objects of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0016]    The accompanying drawing incorporated in and forming a part of the specification, illustrates several aspects of the present invention and together with the description serves to explain the principles of the invention. In the drawing:  
         [0017]    [0017]FIG. 1 is an exploded perspective view of the interchangeable ball hitch of the present invention;  
         [0018]    [0018]FIG. 2 is a side elevational view of the ball hitch of FIG. 1 shown secured to a tow bar;  
         [0019]    [0019]FIG. 3 is a cross sectional view taken along line  3 - 3  of FIG. 2; and  
         [0020]    [0020]FIG. 4 is a detailed bottom plan view of the cap used to secure the ball to the post.  
         [0021]    Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawing. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Reference is now made to FIGS.  1 - 4  showing the interchange-able ball hitch  10  of the present invention. The interchangeable ball hitch  10  includes a post  12  having a threaded mounting stem  14 , an enlarged base collar  16  and a tapered shank  18 . An annular locking track  20 , such as a dove tail channel, is provided at the top of the tapered shank  18 . The annular locking track  20  extends continuously around the shank  18 . A fastener such as a locking nut  19  may be tightened on the threaded mounting stem  14  in order to secure the hitch ball to a tow bar T or other support structure such as a ball mount of a weight distributing hitch.  
         [0023]    Additionally, a cavity  22  is formed in the axial end of the tapered shank  18  remote from the base collar  16 . A detent, generally designated by the reference numeral  26  is secured in the cavity  22 . The detent  26  includes a housing  28  that conforms in size and shape to the cavity  22  so as to be received therein. The housing  28  holds a spring loaded pin  30  the function of which will be described in greater detail below. Preferably, the detent  26  is cinched in place for a positive frictional fit. In one alternative embodiment, the housing  28  and the sidewall of the cavity  22  may be threaded for screw like engagement. Of course, other appropriate mounting arrangements could be utilized.  
         [0024]    The interchangeable ball hitch  10  further includes a hitch ball  32 . As best shown in FIG. 3, hitch ball  32  includes a tapered bore  34  which matches the taper of the tapered shank  18 . Accordingly, hitch ball  32  may be received on and secured to the tapered shank  18 .  
         [0025]    As best shown in FIGS. 1 and 3, the hitch ball  32  also includes a slot  36  which communicates with the tapered bore  34 . When the hitch ball  32  is properly seated on the tapered shank  18 , slot  36  is aligned with the locking track  20  at the top of the post  12 . A unitary locking cap  38  is then secured in position on the locking track  20  to hold the hitch ball  32  to the post  12  in a manner described in greater detail below.  
         [0026]    As best shown in FIG. 4, cap  38  includes a pair of opposed guide rails  40  and a notch  42 . The guide rails  40  are sized, shaped and spaced to engage in the dove tail like channel of the locking track  20 . Accordingly, the cap  38  is secured in position by sliding the cap laterally through the slot  36  in a direction substantially perpendicular to the longitudinal axis of the post  12  and engaging the guide rails  40  in the locking track  20 . As a result, the hitch ball  32  is effectively captured on the tapered shank  18  by the overlying cap  38 . This is because the outer margin or shoulder  46  of the cap  38  engages the shoulder  48  of the ball  32 .  
         [0027]    When the cap  38  is fully and properly seated in position to secure the hitch ball  32  to the post  12 , the spring loaded locking pin  30  of the detent  26  projects into and is received in the notch  42  on the underside of the cap  38 . Thus, the pin  30  provides a positive locking force to secure the cap  38  in position. This structural arrangement provides a double lock of high integrity. Specifically, the guide rails  40  lock in the locking track  20  and the pin  30  locks in the notch  42 .  
         [0028]    As a result of the present structural arrangement, hitch ball  32  is not only prevented from moving along the longitudinal axis of the post  12  but is also free to rotate relative to the tapered shank  18  of the post  12 . This is because the guide rails  40  on the cap  38  freely orbit around the annular locking track  20  while maintaining a secure connection. Advantageously, towing efficiency is increased as the free rotation of the hitch ball  32  on the post  12  minimizes the friction that must be overcome during towing as the vehicle and trailer turn relative to each other. Further, relative free rotation of the hitch ball  32  on the shank  18  prevents any inadvertent loosening of the locking nut  19 .  
         [0029]    In addition, it should be appreciated that the hitch ball  32  is securely held on the post  12 . Specifically, the cap  38  may only be removed when properly aligned with the slot  36  in the hitch ball  32 . In all other positions, the upper margin of the hitch ball  32  which projects above the shoulder  48  functions to block cap removal. Further, even when the cap is properly aligned with the slot  36 , the spring loaded locking pin  30  of detent  26  secured in the post  12  seats in the notch  42  of the cap  38  so as to secure the cap in position.  
         [0030]    Of course, as noted above, a single vehicle is often used for multiple towing applications. Each trailer towed may include a socket for receiving a different size hitch ball. Advantageously, the present invention allows one to quickly and easily match the hitch ball  32  to the size of hitch ball socket of the trailer to allow towing. More specifically, a hitch ball  32  of substantially any standard diameter may be secured to the post  12 . More specifically, each hitch ball  32  is machined to incorporate a tapered bore  34  to match the tapered shank  18  of the ball hitch  10 . In this way, a hitch ball  32  of substantially any desired diameter may be properly seated on the tapered shank  18  so that the slot  36  in the hitch ball is properly aligned with the locking track  20  of the post  12  to allow the locking cap  38  to be secured in place in the manner previously described. Advantageously, this procedure may be performed conveniently and efficiently in a short amount of time without any special tools.  
         [0031]    The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. For example, the hitch ball  32  may be fixed to the post  12  so as to prevent relative rotation therebetween, if desired. This may be accomplished through use of a polygonal shank and mating polygonal hitch ball bore or by some other means. Further, the cap  3   8  may either rotate with the hitch ball  32  or the cap may be keyed to the post  12 . Additionally, alternative configurations of the guide rails  40  and locking track  20  may be utilized. Any shape or configuration of cooperating male and female components could be adopted so as to provide an appropriate interlocking of components (e.g. T-shaped, L-shaped). Further, the male and female components could be reversed. Thus, the track could be provided in the cap  38  and the rail could be provided on the shank  18 .  
         [0032]    The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.