Abstract:
A fifth wheel slide assembly secondary lock includes an elongated cam member supported by a spindle extending upward from a sliding pedestal. A pair of linkage bars are pivotally coupled by one end to opposing ends of the cam member, the other ends of the bars being coupled to wedges operable for selectively engaging slide rails mounted to a vehicle frame in order to maintain a longitudinal position of said pedestal. The pedestal includes at least one stop extending upward from the pedestal at a height that extends above an arc defined by the rotation of the cam.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional App. Ser. No. 61/484,717, filed May 11, 2011. 
    
    
     BACKGROUND 
     1. Field 
     The present invention relates generally to fifth wheel adjusting slide assemblies, and in particular to fifth wheel adjusting slide assemblies with a secondary lock. 
     2. Description of Related Art 
     Many current fifth wheel adjusting slide assemblies use selection wedges that engage opposing, laterally spaced slide rails to hold the fifth wheel&#39;s longitudinal position relative to the slide rail. The wedges are typically held in place in the slide rail by spring force. If the spring becomes dislodged, or fails, the wedges could disengage from the slide rails, and the fifth wheel would slide freely within the slide assembly. If the fifth wheel was coupled to a trailer, the results would be dangerous and catastrophic. 
     SUMMARY 
     For purposes of summarizing the invention, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any one particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     A fifth wheel slide assembly secondary lock includes an elongated cam member supported by a spindle extending upward from a sliding pedestal. A pair of linkage bars are pivotally coupled by one end to opposing ends of the cam member, the other ends of the bars being coupled to wedges operable for selectively engaging slide rails mounted to a vehicle frame in order to maintain a longitudinal position of said pedestal. The pedestal includes at least one stop extending upward from the pedestal at a height that extends above an arc defined by the rotation of the cam. 
     These and other embodiments of the present invention will also become readily apparent to those skilled in the art from the following detailed description of the embodiments having reference to the attached figures, the invention not being limited to any particular embodiment(s) disclosed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. 
         FIG. 1  is an exemplary tractor truck with an exemplary fifth wheel hitch attached to adjacent truck frames; 
         FIG. 1A  is elevational view of an exemplary tractor truck and trailer with a fifth wheel hitch; 
         FIG. 1B  is an exemplary fifth wheel hitch; 
         FIG. 1C  is an exemplary hitch plate; 
         FIG. 1D  is an exemplary prior art fifth wheel slide rail assembly; 
         FIG. 2  is a plan view of an exemplary prior art pedestal assembly showing an exemplary locking configuration; 
         FIG. 3  is a plan view of an exemplary pedestal and locking assembly according to an embodiment of the present invention; 
         FIG. 4  is another plan of view of the assembly of  FIG. 3 ; 
         FIG. 5  is a plan view of the assembly of  FIG. 3 , with the locking wedges retracted; 
         FIG. 6  is a perspective view of the pedestal with locking assembly; and 
         FIG. 7  is another perspective view of the pedestal with locking assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The various embodiments of the present invention and their advantages are best understood by referring to  FIGS. 1 through 7  of the drawings. The elements of the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. Throughout the drawings, like numerals are used for like and corresponding parts of the various drawings. 
     This invention may be provided in other specific forms and embodiments without departing from the essential characteristics as described herein. The embodiments described above are to be considered in all aspects as illustrative only and not restrictive in any manner. The following claims rather than the foregoing description indicate the scope of the invention. 
     Furthermore, reference in the specification to “an embodiment,” “one embodiment,” “various embodiments,” or any variant thereof means that a particular feature or aspect of the invention described in conjunction with the particular embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases “in one embodiment,” “in another embodiment,” or variations thereof in various places throughout the specification are not necessarily all referring to its respective embodiment. 
     Terms such as “aft,” “rear,” “forward,” “front,” “lateral,” or “outward,” or the like, and derivatives thereof are to be understand in relation to the truck or vehicle on which the fifth wheel is mounted. On the other hand, rotational terms such as “clockwise” and “counter-clockwise” are to be understood as viewed in the figure(s) referenced in the detailed description. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     Fifth wheel hitches are well known in the field of towing trailers using a truck or tractor.  FIG. 1  depicts an exemplary tractor and trailer hitch arrangement employing a fifth wheel hitch  103 . Tractor  100  is affixed with a fifth wheel hitch  103  to rear of parallel tractor frame members  105 .  FIGS. 1A through 1C  depict another view of an exemplary tractor and trailer hitch arrangement employing a fifth wheel hitch. Tractor  100  is affixed with a fifth wheel hitch  103  positioned rearward on the tractor frame  105 . Fifth wheel hitch  103  includes a fifth wheel hitch assembly  110  pivotally mounted on slide assembly  155 . Fifth wheel hitch assembly  110  comprises hitch plate  130  which houses a locking mechanism underneath with slot  135  opening toward the aft end of fifth wheel assembly  110  for receiving a kingpin  111  from trailer  119 . 
     Kingpin  111  typically extends downward from a trailer bearing plate  107 , which rests upon fifth wheel assembly, specifically, upon load area  145  of fifth wheel hitch plate  130 . Kingpin is, typically, a unitarily constructed article comprised of a lower flange  115  capping a shank  113  which extends from collar  117 . 
       FIG. 1D  depicts an example of a conventional slide rail where slide rail assembly  120   a  is comprised of left and right slide rail plates  102   a, b  tied in parallel by two or more tie bars  104   a, b  which form slide frame  121 . Left slide rail  151   b  is attached to the upper surface of left slide rail plate  102   a  and right slide rail  151   a  is attached to upper surface of right slide rail plate  102   b  such that fifth wheel hitch assembly  110  and slide assembly  155  are located therebetween, inboard of the left and right slide rails  102   a, b . Slide rail plates  102   a, b  and slide rails  151   a, b  each have longitudinal axes which parallel the longitudinal axis of tractor  109  and are typically mounted, either with welding or fastening, to parallel longitudinal truck frame members (not shown), usually with using interposing angle iron members. 
     Slide stop blocks  105   a - d  are located at each end of each slide rail plate  102   a, b . Slide stop blocks  105   a - d  prevent over travel of slide assembly  155 . As is shown in the illustration, slide rails  151   a, b  of the prior art are typically a flange extending inboard of the assembly, slidably receiving laterally extending flanges  111 ,  114  of slide assembly  155 . Slide rails  151   a, b  typically include gaps, or detents,  176  spaced along the length of the slide rail. 
     The slide assembly  155  may include a means for selectively locking the bracket in position longitudinally with respect to the slide rail assembly. One example, shown in  FIG. 1D , is a pneumatic cylinder  177  mounted in the assembly from which laterally extend plunger arms  173   a, b . A fork member  179  may be mounted to the respective lateral ends of plunger arms  173 , where the fork member includes projections, or prongs,  181  that insert into the slide rail gaps  176  when the plungers arms are extended. The engagement of the projections  181  into the gaps  176 , thus, prevents longitudinal movement of the slide assembly  155 , and, therefore, the fifth wheel assembly. Slide assembly  155  also comprises brackets  165  which provide attachment support for the hitch assembly  110 , configured to allow the hitch assembly to pivot in the longitudinal plane. 
     Referring to  FIG. 2 , another prior art slide assembly is shown with wedges that engage the slide rail and are held in place in the slide rail by spring force. In  FIG. 3 , a new slide assembly arrangement includes a toggle lock. The wedges in this arrangement are also held in place in the slide rail by spring force, but the added toggle lock acts as a back-up. In the event that the wedges begin to disengage from the slide rail, spring force resists this disengagement. If the retraction force on the wedges exceeds the spring force, the toggle lock prevents the wedges from retracting fully from the rail. 
     One end of the wedge linkage bar attaches to the wedge through a bolted joint that rotates freely. The other end of the wedge linkage bar attaches to the toggle cam through a slotted joint that allows for both rotation and linear motion. This liner motion is necessary to allow the wedge to seat fully in the slide rail. In the closed position, the toggle cam rotates over center and rests against the toggle cam stops. 
     As described above and shown in the associated drawings, the present disclosure is drawn to a fifth wheel slide assembly secondary lock. While particular embodiments of the invention have been described, it will be understood, however, that the invention is not limited thereto, since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. It is, therefore, contemplated by the appended claims to cover any such modifications that incorporate those features or those improvements that embody the spirit and scope of the present invention.