Abstract:
A tool for inspecting a trailer kingpin and adjusting a fifth wheel hitch includes a plate having at least two mutually substantially perpendicular sides, one side having upper and lower generally rectangular tabs extending therefrom and separated by a space therebetween, the space being dimensioned to snugly receive a kingpin lower flange, the upper tab being dimensioned to be snugly received along a kingpin shank. Opposing this tabbed side is a side having at least one shaped recess for receiving a means for adjusting play in a fifth wheel hitch and transferring the application of torque thereto. The plate also includes a shaped aperture for receiving a kingpin, the shaped aperture having a substantially rectangular wide portion and a substantially rectangular narrow portion.

Description:
BACKGROUND 
     Description of the Related Art 
     Fifth wheel hitches are well known in the field of towing trailers using a truck or tractor.  FIGS. 1A through 1C  depict an exemplary tractor and trailer hitch arrangement employing a fifth wheel hitch. Tractor  100  is affixed with a fifth wheel hitch  103  to rear of tractor frame  105 . 
     Fifth wheel hitch  103  includes a fifth wheel hitch assembly  110  pivotally mounted on pedestal  155 . Fifth wheel hitch assembly  110  comprises hitch plate  130  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 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 . 
     The condition of the kingpin is a significant factor in the safe towing of trailers. Operations, however, necessarily result in degradation of the kingpin over time to a point where attempting to hitch using a degraded kingpin is unsafe. For example, most, if not all, kingpins used in the fifth wheel coupling are designed to be used when plumb. If the kingpin is off from vertical by even one degree, effective coupling with the hitch may not be achieved and wear on the fifth wheel lock is accelerated. 
     Further, a worn kingpin, either in the collar area or in the shank results in excessive play between the kingpin and the fifth wheel locking mechanism. Many fifth wheel hitches include means by which the play may be reduced in the locking area. But if the kingpin is worn beyond a certain maximum amount, adjusting to decrease the play becomes ineffective in preventing a loose coupling. 
     The Society of Automotive Engineers (SAE) has promulgated standards for the safe configuration and condition of kingpins in SAE  700  which details the points to be checked during a pre-operation inspection of the kingpin. In addition to checking for mounting and wear, the operator should examine the kingpin to see if it extends the proper length from the trailer bearing plate and that the lower flange is of specified size to prevent disengagement of the kingpin from the fifth wheel jaws. 
     A gauge can be used to aid an operator&#39;s inspection of the kingpin for plumb, excessive wear and proper length. Such a gauge has been disclosed in U.S. Design Pat. No. Des. 273, 467, issued to Martin on Apr. 17, 1984. However, an operator, to properly achieve effective coupling of the trailer to the hitch must use other tools to adjust the hitch, for example a wrench. A separate gauge, thus, adds to the number of implements an operator must have on hand. 
     SUMMARY 
     The present disclosure is directed to a tool for adjusting a fifth wheel hitch coupling that advantageously incorporates a gauge for inspection of the kingpin. 
     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 maybe 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 tool for inspecting a trailer kingpin and adjusting a fifth wheel hitch includes a plate having at least two mutually substantially perpendicular sides, one side having upper and lower generally rectangular tabs extending therefrom and separated by a space therebetween, the space being dimensioned to snugly receive a kingpin lower flange, the upper tab being dimensioned to be snugly received along a kingpin shank. Opposing this tabbed side is a side having at least one shaped recess for receiving a means for adjusting play in a fifth wheel hitch and transferring the application of torque thereto. The plate also includes a shaped aperture for receiving a kingpin, the shaped aperture having a substantially rectangular wide portion and a substantially rectangular narrow portion. 
     In a further embodiment, the tool includes more than one shaped recess for the application of torque to the fifth wheel adjustment means. 
     In a still further embodiment, the wide portion of the aperture includes two widths with a transitional region in between. Likewise, the narrow portion of the aperture includes two widths with a transitional region in between. 
     In yet another embodiment, the region of the plate surrounding the shaped recess, or recesses, is thicker than the remaining portions of the plate. 
     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. 1A  is a illustration of a tractor and trailer coupling using a fifth wheel hitch; 
         FIG. 1B  depicts an exemplary fifth wheel hitch; 
         FIG. 1C  is a perspective view of an exemplary fifth wheel hitch plate; 
         FIG. 2A  is a perspective view of a kingpin tool according to one embodiment of the present invention; 
         FIG. 2B  is a plan view of the inventive kingpin tool according to one embodiment of the present invention; 
         FIG. 3A  is an illustration of the use of a plumb gauging portion of the kingpin tool according the present invention; 
         FIG. 3B  is an illustration of the use of a wear gauging portion of the kingpin tool according to the present invention; 
         FIG. 4  is a plan view of the kingpin tool according to an alternative embodiment of the present invention; 
         FIG. 5A  is a plan view of an exemplary fifth wheel hitch plate illustrating exemplary locking and adjusting mechanisms; 
         FIG. 5B  is an illustration of the use of adjustment tool portion of the inventive kingpin tool according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The various embodiments of the present invention and their advantages are best understood by referring to  FIGS. 1 through 4  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 drawing. 
     This invention maybe 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. 
       FIGS. 2A and 2B  depict one exemplary embodiment of the tool  200  according to the present invention displaying a plate  201  having a first side  206  that is substantially perpendicular to an adjacent side  205 . Extending from first side  206  are tabs  202 ,  204  which are separated by space  207 . Tabs  202 ,  204  are substantially rectangular having an outward edge perpendicular to adjacent side  205 . 
     Tool  200  incorporates aperture  210  which is a diameter gauge for a kingpin. Aperture  210  is shaped to have a relatively wider portion  212  and a relatively narrow portion  214 . Formed in a side  215  opposing first side  206 , are one or more open-end wrench spaces  221 ,  222 . Where there are two or more open wrench spaces  221 ,  222 , each such space maybe of a differing size. 
     Use of the gauge portion of tool  200  is shown in  FIGS. 3A and 3B . In  FIG. 3A , tool  200  is oriented to be on edge with respect to ground, and tabs  202 ,  204  positioned toward exemplary kingpin  111 . Upper tab  202  is seated against kingpin shank  113 , with space  207  receiving kingpin lower flange  115 . Kingpin collar  117  rests against the recessed area of first side  203 . Adjacent side  205  placed abutting upper fifth wheel assembly which is mounted to trailer (not shown). Thus, a visual indication of whether the kingpin is plumb may be obtained as a result of the edge of tab  202  being perpendicular with adjacent side  205 . 
     It should be noted that upper tab  202 , space  207  and lower tab  204  are disposed along first side  206  so as to leave an area along the side corresponding to the length of collar  117 . This is so that when the gauge is seated against kingpin and the trailer bearing plate, proper length of the kingpin may also be observed and assessed. 
     The diameter of kingpin collar  117  and shank  113  is checked by placing tool  200  over kingpin  111 , with kingpin  111  inserted through aperture  210 , as shown in  FIG. 3B . Wide portion  212  is of a width that is equal to the diameter of collar  117  less the maximum amount of wear of one-eighth inch. Thus, if collar  117  fits inside wide portion  212 , it is beyond the maximum wear limits and must be replaced. Likewise, narrow portion  214  is of a width that is equal to shank  113  less the maximum amount of wear of one-eighth inch. To check the shank for maximum wear, the inspector attempts to position the narrow portion  214  around the shank. If shank  113  fits inside narrow portion  214 , it is beyond the maximum wear limits and must be replaced. 
       FIG. 4  shows an exemplary alternative embodiment of the inventive tool  400  wherein aperture  410  comprises a wide portion  412  and a narrow portion  414 . Wide portion  412  is composed of a sub-portion of a first width  402  transitioning relatively gradually, through a first transitional region  420 , to a sub-portion of a second width  404 . Likewise, narrow portion  414  is composed of a sub-portion of a third width  403  transitioning relatively gradually, through a second transitional region  422 , to a sub-portion of a fourth width  405 . 
     Wide portion  412  is again used to gauge the wear on kingpin collar  117  by placing tool  400  over kingpin  111 , with kingpin inserted through aperture. In this embodiment, the first width  402  is slightly wider than the diameter of an unworn kingpin collar  117 , and second width  404  is substantially equal to that diameter less the maximum wear allowed by applicable governing standards (e.g., one-eighth inch). Thus, if collar  117  fits within second width  404 , the wear is greater than the maximum allowed and the kingpin must be replaced. However, unlike the previously discussed embodiment, first transitional region  420  provides a visual indication of the progress of wear on collar  117  and gives an operator the option of exchanging a worn kingpin for an unworn kingpin prior to wear exceeding limits. In addition, tool  400  may be imprinted, engraved or embossed with indicia  430 ,  431  to provide further visual explanation of whether collar  117  has worn beyond acceptable limits  431 , or is yet usable  430 . 
     Narrow portion  414  is a gauge of wear on kingpin shank  113  by placing kingpin  111  through wide portion  412  of aperture  410  and positioning tool  400  so that shank  113  is inserted through third width  403 . Third width  403  is slightly wider than the diameter of an unworn shank  113 , and fourth width  405  is substantially equal to that diameter less the maximum wear allowed by applicable governing standards (e.g., one-eighth inch). Thus, if shank  113  fits within fourth width  405 , the wear is greater than the maximum allowed and the kingpin must be replaced. Like first transitional region, second transitional region  422  provides a visual indication of the progress of wear on shank  113  and permits an operator to decide to change the worn kingpin out prior to the wear actually exceeding limits. Again, tool  400  may be imprinted, engraved, or embossed with indicia  440 ,  441  to provide further visual explanation of whether shank  113  is worn beyond acceptable limits  441 , or remains in an operable condition  440 . 
     Many fifth wheel assemblies comprise a means to vary the amount of space between the kingpin and the jaws of the fifth wheel, or “play” when the kingpin is engaged within the slot. Referring to  FIG. 5 , shown is a top view of an exemplary fifth wheel hitch assembly  500  incorporating an exemplary means is a threaded rod  505  extending to a wedge member  507  abutting a movable jaw member  509 . During coupling operation, movable jaw member  509  receives a kingpin and holds it against fixed jaw  506 . 
     Rod  505  extends through the wall of fifth wheel hitch plate  130  and can be turned by application of torque to hexagonal cap  511 . Rotation of hexagonal cap rotates threaded rod  505  which moves block  507  laterally inward or outward with respect to movable jaw member  509 , thereby increasing or decreasing the play. This apparatus is more clearly described in greater detail in co-owned U.S. Pat. No. 5,641,174 issued Jun. 24, 1997, to Terry, et al. and incorporated by reference herein. 
     To advantageously decrease the number of implements an operator must have on hand, tool  200  comprises one or more open end wrench spaces  221 ,  222 . When kingpin is engaged within fifth wheel, tool  200  may be used by simply placing wrench space over the hexagonal cap and applying torque thereto through leverage applied to tool  200 . Wrench space(s) may be of any appropriate size to match the size of any hexagonal cap used. Non-limiting examples of sizes are one and one-sixteenth inch and fifteen-sixteenth inch, which are sizes found on many fifth wheel assembly systems. 
     The inventive tool disclosed hereinabove may be comprised of any suitable material including metals, metal alloys, and suitably durable and strong polymerics. It may be formed from casting or injection molding or other forms of manufacturing known in the arts. Thickness of tool maybe uniform, but where weaker materials are used, it is preferably thicker in the region of the wrench spaces, for example, twice that of the remainder of the tool, in order to support the application of torque. Whether the thickness of the region near the wrench spaces is thicker depends upon the material used as would be appreciated by those skilled in the relevant arts. A prototype has been formed using polypropylene with a thickness in the wrench space region of approximately 0.5 inches, and a thickness for the remainder of the tool of approximately 0.25 inches. 
     As described above and shown in the associated drawings, the present invention comprises an apparatus for a kingpin inspection gauge and fifth wheel adjustment tool. While particular embodiments of the invention have been described, it will be understood, however, that the invention is not limited thereto, since modifications maybe 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.