Patent Document

RELATED APPLICATIONS 
     Priority 
     This application claims priority to U.S. Provisional Patent Application No. 61/033,291, filed Mar. 3, 2008, which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     This application discloses devices for attaching an item to a vehicle. More specifically, the present application relates to trailer hitches configured to hold items to a vehicle. 
     BACKGROUND 
     Trailer hitches connect a vehicle to a load. Many common vehicles are configured for standard ball hitch applications, in which a ball is attached to the vehicle and a load is attached to a trailer coupler. The ball and coupler are able to freely pivot with respect to one another. 
     These towing vehicles are often configured to accept standard ball hitches through a trailer hitch receiver. The ball hitch and trailer hitch receiver contain a hole for a retaining pin. This retaining pin ensures that the trailer hitch remains within the trailer hitch receiver, such that the vehicle is redundantly connected to the load. 
     In some loads, such as a horse trailer, movement is desirable as movement between the ball and trailer coupler is necessary for the vehicle and trailer to adapt to changes in the road. Thus, movement between the ball hitch and trailer hitch is not of concern. 
     In other loads, such as an advertising sign or bike rack, movement between ports of the hitch is not desirable. It is desirable that a rigid load hitch engages a standard trailer hitch receiver with minimal, if any movement. It is also desirable to retain the retaining pin configuration. 
     SUMMARY 
     Embodiments of improved rigid trailer hitches and associated methods and implements are disclosed. 
     According to some embodiments, a wedge may be configured to move up a shank within a trailer hitch receiver such that movement of the trailer hitch within the trailer hitch receiver is significantly reduced while also retaining the ability to insert a retaining pin. 
     According to other embodiments, a split wedge may be configured to move along a retaining pin such that movement of the trailer hitch within the trailer hitch receiver is significantly reduced while also retaining the ability to contain a retaining pin. 
     These and other embodiments of a trailer hitch are disclosed herein in a movement reducing trailer hitch as shown and described in the following figures and related description. It will be appreciated that the description and figures are only exemplary of the invention and are not intended to narrow the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of a trailer hitch are shown and described in reference to the numbered drawings wherein: 
         FIG. 1  shows a perspective view of an assembled rigid trailer hitch in accordance with the principles of the present invention; 
         FIG. 2  shows an exploded view of the rigid trailer hitch as seen in  FIG. 1 ; 
         FIG. 3  shows a cross-section of  FIG. 1  perpendicular to the shank&#39;s retaining pin slot; 
         FIG. 4  shows a cross section of the rigid trailer hitch in  FIG. 3  contained within a trailer hitch receiver; 
         FIG. 5  shows a cross section of a rigid trailer hitch with a split wedge; 
         FIG. 6A  shows an end view of a trailer hitch mounted in a hitch receiver with a load attached thereto; 
         FIG. 6B  shows a side view of the trailer hitch and load of  FIG. 6A ; and 
         FIG. 7  shows a multifunction trailer hitch made in accordance with principles of the present invention. 
     
    
    
     It will be appreciated that the drawings are illustrative and not limiting of the scope of invention which is defined by the appended claims. The embodiments shown accomplish various aspects and objects of the invention. It is appreciated that it may not be possible to clearly show each element and aspect of the invention in a single FIGURE, and as such, multiple figures are presented to separately illustrate the various details of exemplary embodiments in greater clarity. Similarly, not every embodiment need accomplish all advantages of the present invention. 
     DETAILED DESCRIPTION 
     Embodiments of a rigid trailer hitch assembly and accompanying drawings are discussed in reference to the numerals provided therein so as to enable one skilled in the art to practice the present invention. The drawings and descriptions are exemplary embodiments of various aspects of a rigid trailer hitch assembly and are not intended to narrow the scope of the appended claims. 
     Turning now to  FIG. 1 , a perspective view is provided of a rigid trailer hitch attachment, generally indicated at  10 . The trailer hitch attachment  10  includes a shank  20  and an attachment member  30  which may engage the shank  20  to improve holding of the shank  20  within a trailer hitch receiver  304  ( FIGS. 4-7 ). The attachment member  30  includes a wedge  40  which may slide relative to the shank, such as, for example on a compound miter  50  of the shank  20 . (A compound miter  50  is preferred to provide improved holding both vertically and horizontally, although an improvement can be achieved with a configuration which works in only one direction). 
     A rod  60  extends through the shank  20  and may engage the attachment member  30  in a threaded engagement as will be explained below. A rod head  70  may be attached to the end of the rod  60 . When the rod head  70  is rotated in one direction, a threaded end  130  ( FIGS. 2-5 ) of the rod  60  may engage the attachment member  30  and generate a force that causes the attachment member main body  120  ( FIGS. 2-3 ) to move further within the shank  20 , i.e. toward the rod head. This movement may also cause the wedge  40  to slide further up the compound miter  50  of the shank  20 . As the wedge  40  slides further up the compound miter  50 , a force is exerted perpendicular to the longitudinal axis of the shank  20 . When the rigid trailer hitch attachment  10  is within a trailer hitch receiver  304  ( FIGS. 4-7 ), this force may engage the walls  300  of the trailer hitch receiver  304  and cause the rigid trailer hitch attachment  10  to remain substantially rigidly in place. This rigidity is in sharp contrast to where a shank of the prior art is inserted into the trailer hitch receiver  304  and differences between the outside dimensions of the shank and the inside dimensions of the trailer hitch allow movement between the two which is amplified by any item attached to the shank. 
     When the attachment member  30  is placed within the shank  20 , a retaining pin slot  80  is able to accept a retaining pin  410  ( FIGS. 4-7 ). When properly placed, the retaining pin slot  80  lines up with a corresponding slot  380  ( FIG. 7 ) in the trailer hitch receiver  304  such that a retaining pin  410  travels through the trailer hitch receiver  304 , shank  20  and attachment member  30 . Should the rigid trailer hitch&#39;s  10  friction be insufficient to hold the rigid trailer hitch  10  within the trailer hitch receiver  304 , the retaining pin  410  provides sufficient force to keep the rigid trailer hitch attachment  10  within the trailer hitch receiver  304 . Utilizing the retaining pin  410  ensures that the rigid trailer hitch attachment  10  and its attachments are not suddenly dropped from the trailer hitch receiver  304  behind a vehicle. 
     Turning now to  FIG. 2 , there is shown an exploded view of the rigid trailer hitch attachment  10  seen in  FIG. 1 . The shank  20  may contain a longitudinal hole  100  and the rod  60  may be placed in the longitudinal hole  100 . The rod  60  may be held in place by a rod retainer  160  having a rod head  70  of a larger diameter than the longitudinal hole  100  and a central abutment having a washer  110   a  attached to the rod  60 . The washer  110   a  can be welded or otherwise attached to or formed with the rod  60 , and the rod head  70  may be attached to the rod  60  by welding or some other attachment mechanism. The fixed nature of the rod could also be reversed. 
     The attached washer  110   a  may form a flange of a larger diameter than the longitudinal hole  100  and prevent the rod  60  from advancing longitudinally out of the hole  100  toward the rod head  70 . Likewise, the rod head  70  may prevent longitudinal movement of the rod  60  in the opposite direction. Another washer  110  may be used between the rod head  70  and the shank  20  to facilitate rotation of the rod  60 . 
     The rod  60  may connect to the attachment member body  120 . This connection can be accomplished through a threaded end  130  to the rod  60  and a threaded hole  140  within the attachment member body  120 . A rotational motion of the rod  60  may cause the attachment member  30  to engage or release the rod  60  according to the rotation direction and threading of the threaded end  130  and threaded hole  140  combination. 
     The attachment member body  120  may contain a body slot  150  configured to work in conjunction with the retaining pin slot  80  in the shank  20 . The body slot  150  may be configured to be larger than the retaining pin  410  ( FIGS. 4-7 ) such that adjustments that cause movement of the attachment member  30  may not interfere with the ability of the retaining pin  410  to pass through the attachment member body  120 . 
     Various embodiments of the assembly of rigid trailer hitch attachment  10  components can be dependent upon use. For example, in light usage, such as sign or bike carrier attachments, a plastic, resin, aluminum, or light weight or low-cost material may be sufficient for some or all of the components, while reducing overall weight as compared with steel. For heavier loads, steel or other materials of a similar strength may be desired. 
     Turning to  FIG. 3 , a cross-section of  FIG. 1  perpendicular to the retaining pin slot  80  of the shank  20 , the inner working parts of the rigid trailer hitch  10  are shown. The attachment member body  120  may slide into a shank cavity  200  within the shank  20 . Movement of the attachment member  30  may be limited to the plane of compound miter  50  of the wedge  40  by contact between the attachments member  30  and the wedge  40 . Rotating the rod  60  such that more of the threaded end  130  is engaged within the attachment member body  30  causes the wedge  40  to travel up the compound miter  50 . This travel may increase the effective distance between the top  210  of the wedge  40  and the opposite corner  200  of the shank  20 . 
     The rod retainer  160  of the rigid trailer hitch attachment  10  may reduce or prevent lateral movement of the rod  60 . The members of the rod retainer  160  are best illustrated in  FIG. 3 . The rod retainer  160  generally includes the washers  110 , the rod head  70 , and the threaded end  130 . In the illustrated embodiment, rod  60  is contained within the longitudinal hole  100  by a set of washers  110 . The washers  110  have an outside diameter larger than the longitudinal hole  100  and an inner hole diameter that is less than that of the rod head  70  and the threaded end  130 . Such embodiments of rod retainers  160  may minimize longitudinal movement of the rod  60  within the longitudinal hole  100 . Rotating the rod head  70  in the opposite direction may affirmatively disengage wedge  40  and opposing corner  220 . 
     Turning to  FIG. 4 , a cross-sectional view of the rigid trailer hitch  10  of  FIG. 3  is shown contained within a trailer hitch receiver  304 . The trailer hitch receiver walls  300  provide a surface for an upper surface  210  of the wedge  40  to engage with, and an opposing rigid surface for the a lower surface  220  of the shank  20  to engage with. As the head  70  of the rod  60  is twisted one way, the threaded end  130  of the rod  60  may engage the attachment member body  120  and pull the attachment member body  120  further within the shank  20 . As the attachment member body  120  is pulled further within the shank  20 , the wedge  40  may then slide up the compound miter  50 . As the wedge  40  slides up the compound miter  50 , the wedge  40  may then push against the upper surface  210  of the trailer hitch receiver walls  300 , causing firm engagement of shank  20  within trailer hitch receiver  304 . The corresponding return force of the upper surface  210  may then cause the shank  20  to engage the lower surface  220 . The engagement of the wedge  40  and the shank  20  against the trailer hitch receiver walls  300  may provide rigidity to the rigid trailer hitch  10 . Correspondingly, if the head  70  of the rod  60  is twisted in the opposite direction, the rigid trailer hitch  10  may then disengage from the trailer hitch receiver walls  300 . 
     Turning to  FIG. 5 , a cross section of a rigid trailer hitch  10  with an attachment member in the form of a split wedge body  400  is shown within trailer hitch receiver walls  300 . The rigid trailer hitch  10  is shown inserted within the trailer hitch receiver walls  300 . A retaining pin  410  may be inserted in between the upper wedge  420  and the lower wedge  430 . The head  70  of the rod  60  may then be turned to causes the thread end  130  of the rod to engage the split wedge body  400  and draw the split wedge body  400  toward the shank  20 . As the split wedge body  400  is drawn toward the shank  20 , the retaining pin  410  may then cause the upper wedge  420  and the lower wedge  430  to deform outwards and press against the trailer hitch receiver walls  300 . As the upper wedge  420  and lower wedge  430  engage the trailer hitch receiver walls  300 , the combined force of the upper wedge  420 , lower wedge  430 , and the retaining pin  410  may contribute to the rigidity of the rigid trailer hitch  10 . 
     The shank  20  can be held stationary by a flange  440  on the shank  20  in front of the trailer hitch receiver walls  300 . Reduced movement of the shank  20 , in comparison with the split wedge body  400  may aid the retaining pin  410  in separating the upper wedge  420  and the lower wedge  430 . Splitting the upper wedge  420  and lower wedge  430  may thus result in producing the necessary force against the trailer hitch receiver walls  300  to hold the shank  20  firmly within trailer hitch receiver  304 . 
     While  FIG. 5  shows the retaining pin  410  not passing through the shank, it will be appreciated that the angle of the engagement between the retaining pin and the upper wedge  420  and lower wedge  430  may be such that it would allow the shank to extend past and receive the retaining pin. In such embodiments, the attachment member that forms the split wedge body  400  cannot be pulled out of the receiver  304  because the thickness of the upper wedge  420  and lower wedge  430  are greater than the distance between the retaining pin  410  and the trailer hitch receiver walls  300 . 
     Either of the embodiments shown herein may provide a marked improvement in the rigidity of anything attached to the shank  20 . The trailer hitches  10  disclosed in this application have almost no play between the shank  20  and the trailer hitch receiver  304 , unlike a conventional shank of a conventional trailer hitch. Thus, rather than having a trailer, bike rack, sign, or other load to the shank  20  swaying back and forth on the back of a vehicle, the shank  20  may be held substantially rigid, with substantially little or no lateral movement of whatever is attached to the shank, relative to the vehicle. 
     Turning now to  FIGS. 6 and 6A , there is shown an end view and a side view of the trailer hitch  10  (or  10 ′) mounted in the hitch receiver  304 . In some embodiments, the trailer hitch  10  may be held in place by turning the rod head  70  to rotate the rod  60  and engage the wedge  40  of wedges  420 ,  430  as discussed above. While conventional trailer hitches will pivot side to side due to the tolerances necessary to insert the hitch into the receiver, embodiments of the trailer hitch  10  may hold the shank  20  firmly, substantially eliminating side-to-side movement of a load  450  attached to a vehicle through the shank  20 . Those skilled in the art will appreciate that the load  450  may be an advertising sign, a bike rack, a trailer, or any other item attachable to the shank  20  and for which pivoting back and forth is undesirable. With the pin  410  installed, the trailer hitch  10  or  10 ′ disclosed within this application has all the retaining ability of a conventional trailer hitch, but may provide a substantial improvement in holding the load  450  stable. 
     Additionally, the rod head  70  may allow for easy attachment and removal of the trailer hitch  10 . Once mounted in the trailer hitch receiver  304 , the rod head  70  need only be rotated in one direction to secure the shank  20  within the hitch receiver  304 . While the wedging action of the trailer hitch  10  in the receiver  304  may ordinarily make removal of the trailer hitch  10  difficult, rotating the rod head  70  in the opposite direction forces the wedges away from the rod head  70  and makes the trailer hitch  10  easy to remove. 
     Turning now to  FIG. 7 , there is shown a perspective, partially exploded view of an embodiment of a multifunction trailer hitch  500 . The multifunction trailer hitch  500  may include several aspects of embodiments of the trailer hitch  10  described above, as well as additional aspects that will be described below. It will be appreciated that these aspects can be incorporated into any of the embodiments discussed above. For example, the embodiments above are discussed primarily in the context that tightening the rod head  70  and rod  60  will draw the wedge  40  along the compound miter  50  and thereby hold the shank  20  tightly in the trailer hitch receiver  304  to prevent lateral pivoting of a load  450  carried by the shank  20  or the two wedge system discussed in  FIG. 5 . As shown in  FIG. 7 , however, the shank  20  may be attached to a ball  504  for towing a trailer, or other device using a ball attachment. The ball  504  may be mounted directly on the shank  20  or may be attached by an intervening structure, such as arm  508 . The arm  508  may be directly attached, i.e. formed integrally therewith or welded (etc.) to the shank  20 , or may be removably attached. 
     When towing a trailer, pivoting of the shank  20  from side to side may not generally be a great concern from the point of view of the load, because the ball  504  may allow for some movement as well. However, in accordance with some embodiments, using the shank  20  and receiver  304  is advantageous because it may substantially reduce noise, and may reduce trailer sway in some circumstances. Traditional shanks tend to vibrate and rattle within the receiver, while, as discussed above, the shank  20  may be held firmly within the receiver  304  by tightening the rod  60 . The secure engagement of the shank  20  may substantially reduce movement between the shank and the receiver  304 , thereby reducing rattling as the vehicle travels along a road. 
     Another aspect of embodiments illustrated in  FIG. 7  includes a second receiver  304 ′, which may be attached to the shank  20 , thereby acting as a load similar to  450  in  FIGS. 6 and 6A . This may allow for a second shank  20 ′ to be mounted into the receiver  304 ′, thus providing a multifunction trailer hitch  500 . If, for example, in the event that a person wished to tow a trailer behind their vehicle and to also have a bike rack or sign carried by the trailer hitch as well, the multifunction hitch  500  may allow both to be accomplished. The ball  504  may be used to tow the trailer, while the engagement between the second receiver  304 ′ and the second shank  20 ′ can be used to attach the bicycle rack, sign, etc. If the bicycle rack or sign is no longer needed, the second shank  20 ′ can be removed without removing or otherwise affecting the trailer engaging the ball  504 . Likewise, two different bike racks, signs, etc. could be mounted with one being removable independent of the other. One could be mounted directly to shank  20 , while the other is attached to shank  20 ′ which may be longer to provide spacing between the two loads. 
     For the sake of brevity, only one second receiver  304 ′ and second shank  20 ′ are shown. It will be appreciated, however, that some embodiments may include multiple secondary shanks and receivers, and could be used to enable multiple different loads (or a load which is better served by multiple attachment points) to be carried by the multifunction trailer hitch  500 . Embodiments of multifunction trailer hitch  500  may also allow such loads to be carried securely and with less movement and rattling than conventional hitches. Such embodiments may also allow several loads to be added or removed independently of each other. Further, it will be appreciated that other embodiments may use the invention as an extender with a second receiver  304 ′ in line with the receiver  304  rather than at a right angle as shown in  FIG. 7 . 
       FIG. 7  also illustrates the holes  80  in the shanks  20 ,  20 ′ and the holes  380  in the receivers  304 ,  304 ′, which form a slot for a pin  410 . The retaining pin  410  ( FIG. 6 ) may extend through each shank and its respective receiver to ensure retention even if the shanks were otherwise not securely mounted. 
     Some embodiments may include a quick release  512 . Rather than using a rod head  70  on the rod  60 , the second shank  20 ′ shows the use of a quick release  512 . The quick release  512  may include a cam  516  and an arm  520  extending from the cam  516 . Rather than rotating the rod head  70 , the quick release  512  can be used to rotate the rod  60  ( FIGS. 1-6 ) until the wedge  40  is moved sufficiently up the compound miter  50  that it starts to secure the shank  20 ′ in the hitch receiver  304 ′. The arm  520  is then used to rotate the cam  516  which pulls the rod  60  and other structures (see discussion in  FIGS. 1-6  above) outwardly to move the wedge  40  ( FIGS. 1-4 ) or wedges ( FIG. 5 ) toward the quick release  512  and into secure engagement between with the inside wall  300  of the receiver  304 ′. Those of skill in the art will be familiar with such cam mechanisms, such as those used on many bicycle hubs to hold the wheel to the forks. While only shown on the second shank  20 ′, it will be appreciated that both shanks could have the quick release  512  to facilitate more rapid and toolless attachment and removal of the shanks  20 ′ from the receivers  304 ′. 
     There is thus disclosed embodiments of an improved rigid trailer hitch  10 ,  500 . It will be appreciated that the elements shown in one drawing could be used in conjunction with the other drawings, and illustrate exemplary embodiments. For example, the quick release  512 , the attachment mechanism for a ball, and/or the two shank system shown in  FIG. 7  could be used with any of the other embodiments. Likewise, the internal structures or load attachment mechanisms discussed in  FIGS. 1-6  could be used in conjunction with the general concept shown in  FIG. 7 . Other combinations of features discussed herein may also be provided without departing from the scope of the claims. 
     Likewise, it will be appreciated that numerous changes may be made to the present invention without departing from the scope of the claims. The appended claims are intended to cover such modifications.

Technology Category: 7