Abstract:
A tailgate apparatus on vehicle bodies mounted so that the tailgate opens by pivoting about a horizontal axis or rotates about either one or both of the outer vertical axes as desired for unloading of the content of the vehicle body or container. The tailgate may be split and hinged in barn door fashion or it may be one-piece and hinged on a single side, while simultaneously hinged in dump fashion at the top. The hardware design of the apparatus allows dual rotatable opening of the tailgate or overhead dump opening of the tailgate.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to tailgate or end-gate devices implemented on transport-type vehicles used in material handling industries and businesses, such as hauling, shipping, construction, excavation, refuse, storage, maintenance, and light industrial and commercial applications. More particularly, this invention relates to pivotable “dump-style” tailgates, and split tailgates that are dually rotatable. 
     Generally, transport vehicles used for material handling are equipped with tailgates designed to fulfill one function; often these tailgates take one of two forms. The first type is a dump-style tailgate that pivots about a horizontal axis at the top of the tailgate while latching at the bottom during transit. The second design has a side hinge and rotates about a vertical axis in barn door fashion; this type of tailgate has been created using both a single door or split door construction. 
     Dump-style tailgates (those that pivot about a horizontal axis at the top) are usually designed for vehicle beds that can be raised in the front causing the material contained to shift to the rear of the bed where it is dumped through the tailgate. Although this tailgate design provides an expedient way to unload material with relatively little manpower, the dump-style tailgate does not provide easy access to the vehicle bed. As a result, situations requiring material to be loaded and unloaded by hand or calling for any other accessibility to the vehicle bed would be complicated by a dump-style tailgate design. 
     In such cases, a side-hinge tailgate (one that rotates about a vertical axis on the side of the tailgate) provides more accessibility to the vehicle bed. A one-piece door construction is hinged on a vertical axis at an end of the tailgate allowing a single tailgate door to open to one side. Though the tailgate door permits ready access to the vehicle&#39;s bed, it can be problematic where the vehicle faces space constraints. For example, a vehicle loading or unloading in a confined space, such as a tight alleyway or between trees, may not have adequate room for the tailgate door to fully open where its width is equal to that of the vehicle bed itself. Thus, in tight spaces such a tailgate would be useless. An alternate side-hinge tailgate has been developed to combat space constraints in which the door is split and hinged on both vertical ends of the tailgate so that each door panel dually rotates about a vertical axis. By splitting the tailgate door, only a portion of the entire bed width is needed to open the door, thereby minimizing the inability to load and unload in narrow spaces. 
     In each of these constructions, however, the user is still limited to either the dump-style or side-hinge door-style tailgate and the limitations of each design&#39;s use. Very few tailgates have been designed which permit the user to alternate between use of the same tailgate as either dump or side-hinge style. However, those tailgates that have been designed to operate as both dump and side-hinge style pose several drawbacks. For example, these dual-purpose tailgates ordinarily employ the one-piece side-hinge style door, creating difficulties in confined spaces as mentioned above. Additionally, the operator&#39;s safety is compromised where the operator must disengage the door latch to use the dump-style gate at the rear of the vehicle. Present split-door style tailgates often position the door latch in the center of the tailgate forcing the operator to stand directly in front of the vehicle bed. If material shifts during transport, the operator could suffer serious injuries by opening the centrally located door latch because he will be standing directly in front of the load when it falls from the vehicle bed. 
     Bontrager has developed one type of dually operable tailgate disclosed in U.S. Pat. No. 6,015,191. The Bontrager invention uses a type of dump-style tailgate, but also permits the operator to use the tailgate as a side-hinge gate. The side-hinge gate on the Bontrager invention can be built as either a one-piece or split tailgate; however, the split gate has only one centrally located door latch which appears to require the operator to manually open the latch while standing directly behind the tailgate doors. If materials in the vehicle bed shifted during transport, the operator&#39;s safety could be jeopardized if material fell from the vehicle bed when she opened the central door latch. Additionally, the Bontrager apparatus does not indicate any specialized construction to insure the split door configuration retains its rigidity and alignment while the door is used as a dump-style tailgate. Again, such rigidity and alignment is important for safety reasons. If the tailgate fails to maintain its rigid structure and alignment, it could collapse during transport or while unloading material, resulting not only in loss of the load, but potentially causing personal injury to operators and bystanders. 
     OBJECTS &amp; ADVANTAGES 
     Accordingly, several objects and advantages of the present Patent Application of Bucks Fabricating, a division of Deist Industries, Inc. for “Tailgate Apparatus Operable as Either a Split Rotatable or Pivotable Gate” are: 
     1. To provide a tailgate apparatus for transport-type vehicles useable as either a dump-style (hinged along the top of the tailgate and pivotable on a horizontal axis), or as a split side-hinge tailgate (hinged at each side of the tailgate and dually rotatable along a vertical axis). 
     2. To provide a more reliable dual purpose tailgate by aligning the side-hinge doors more tightly to increase the rigidity of the structure, thus preventing buckling of the doors. 
     3. To provide a more convenient tailgate apparatus for operations requiring dump-style applications while also needing ready access to the vehicle bed. 
     4. To provide a tailgate apparatus designed for use in spaces where a split side-hinge door construction requires less space to access the vehicle bed. 
     5. To provide a dual purpose tailgate that affords greater safety protections to the operator and to any bystanders where: 
     (a) The dump gate latch is released at the front of the vehicle bed preventing material from spilling onto the operator. 
     (b) The split side-hinge door latches are disengaged by a release handle located on the side of the door opening preventing material from spilling onto the operator. 
     (c) The split door alignment is designed for greater rigidity to prevent buckling of the doors during transit or operation. 
     6. To provide a dual-purpose tailgate that is simpler to operate where it uses a forward release latch system and fewer pins are needed in interchanging between door uses. 
     SUMMARY 
     In accordance with the present invention a two-piece tailgate apparatus operable as either a rotatable or pivotable gate comprises both a rotatable and pivotable mount enabling the tailgate to rotate about either horizontal or vertical axes so that the tailgate door panel(s) open on one or both ends, or alternatively along the top. The tailgate apparatus encompasses safety features allowing the operator to open the door panel(s) without being directly in front of the cargo area. Additionally, the door panel(s) are designed to use angular locking and positioning mechanisms to create a more rigid tailgate structure that prevents buckling and collapsing of the door panel(s) during operation. 
    
    
     DRAWINGS—FIGURES 
     In the drawings, closely related figures have the same number but different alphabetic suffixes. 
     FIGS. 1A and 1B show front views of the tailgate apparatus and its general construct; FIG. 1C shows an exploded top view of the tailgate apparatus to show the unique alignment locking feature of the tailgate doors. FIG. 1D shows another front view of the tailgate apparatus with the safety chains in a crossed position as they would be when the apparatus was used as a dump-style tailgate or during transit. 
     FIGS. 2A to  2 C show various aspects of the side view of the vehicle body that provide further indications of how the tailgate apparatus operates as either a dump-style or split-door style tailgate. 
     
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 DRAWINGS - REFERENCE NUMERALS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 6 
                 dump-swing hinge bracket 
                 7 
                 upper door hinge 
               
               
                 8 
                 door hinge pin 
                 9 
                 lower door hinge 
               
               
                 10 
                 dump latch 
                 11 
                 dump latch bar 
               
               
                 12 
                 safety chains 
                 14 
                 alignment locks 
               
               
                 16 
                 latch loop 
                 18 
                 cam lock 
               
               
                 20 
                 positioning fork 
                 22 
                 bushing 
               
               
                 24 
                 extension bar 
                 25 
                 cam actuator 
               
               
                 26 
                 ratchet binder 
                 28 
                 pivot bar 
               
               
                 30 
                 positioning bracket 
                 32 
                 door chain 
               
               
                 34 
                 door panel 
                 36 
                 vehicle bed 
               
               
                 38 
                 dump latch safety release 
                 40 
                 chain fastener 
               
               
                 42 
                 dump latch release safety chain 
                 44 
                 vehicle bed side wall 
               
               
                 46 
                 front vehicle bed 
                 48 
                 door hinge pin holder 
               
               
                 49 
                 rear vehicle bed 
               
               
                   
               
             
          
         
       
     
    
    
     DETAILED DESCRIPTION 
     FIGS.  1 A to  1 D—The Preferred Embodiment 
     FIGS. 1A and 1B show a front view of the tailgate apparatus as it would appear if used in a split-door style application; the tailgate apparatus is attached to a vehicle body having a cargo bed. There are two door panels  34  that are each connected to respective dump-swing hinge brackets  6 ; these swing hinge brackets  6  also connect the tailgate to the vehicle body allowing the tailgate to move pivotably about a horizontal axis at the top. Each door panel  34  has an upper door hinge  7  and a lower door hinge  9  that is attached to the door panel  34 . The upper door hinge  7  is attached to the door panel  34 , but not to the vehicle body itself The top piece of the lower door hinge  9  is attached to the door panel  34 , but the bottom piece of lower door hinge  9  is attached to the vehicle body. These hinges ( 7  and  9 ) permit the door panels  34  to rotate about a vertical axis at one or both ends of the tailgate apparatus. A door chain  32  is connected to the door and can be attached to the chain fastener  40  while not in use. The dump latch bar  11  is attached at the bottom of the door panel  34 ; the dump latch  10  can be engaged or disengaged from the dump latch bar  11  so that the door panel  34  is secured or unsecured to the vehicle body at the bottom. While the dump latch  10  is disengaged from the dump latch bar  11 , the door panels  34  can pivot about the horizontal axis at the top of the tailgate. The safety chains  12  on the door panels  34  are fastened to chain fasteners  40  on the door panel to allow them to be crossed or uncrossed as needed during operation or in transit. 
     Two latch loops  16  are attached to the right door panel  34 ; the positioning bracket  30  and positioning fork  20  are also attached to the right door panel. The positioning bracket  30  and positioning fork  20  have corresponding parts on the opposing door panel  34  that provide a tight, angular fit when the latch loops  16  are in a closed position. 
     The pivot bar  28  is attached to three bushings  22  that are connected to the left door panel  34 ; the pivot bar  28  is also connected to two cam locks  18  that may engage and disengage with the latch loops  16 . The pivot bar  28  is connected to the cam actuator  25 , which is in turn connected to the extension bar  24 . The extension bar  24  is connected to the ratchet binder  26 , and the extension bar  24  is attached to the door panel  34  along the left edge opposite the pivot bar  28 . 
     The construct of the left door panel  34  along its edge mirrors that of the right door panel  34 . It encompasses a dump-swing hinge bracket  6 , an upper door hinge  7 , a lower door hinge  9 , a door hinge pin  8 , a door chain  32 , a chain fastener  40 , a dump latch  10 , and a dump latch bar  11 . 
     FIG. 1B shows the same front view of the tailgate apparatus as FIG. 1A, but illustrates the tailgate apparatus in split-door style where one door panel  34  is open. FIG. 1B shows the vehicle bed  36  where the right door panel  34  is open and the latch loops  16  are disengaged from the cam locks  18  so the slit-door panel  34  is in an open position. 
     FIG. 1C shows a top view of the door panels  34  illustrating a close-up depiction of the alignment locks  14 ; the alignment lock has a piece attached to each door panel  34  so that when the door panels  34  are in a closed position, the alignment locks form a tight, angular fit. FIG. 1C also shows the top view of the extension bar  24  as it connects to the cam actuator  25 . 
     FIG. 1D shows the same front view of the tailgate apparatus as shown in FIG. 1A; however, FIG. 1D shows the safety chains  12  in a crossed position where the safety chains  12  are attached to the chain fasteners  40  on the door panel  34 . Each safety chain  12  is fastened to the chain fastener  40  on the opposite door panel  34  than that to which the safety chain  12  is attached. 
     FIGS.  2 A to  2 C—Additional Embodiments 
     FIGS. 2A to  2 C illustrate various side views of the vehicle body indicating how the tailgate apparatus is used in conjunction with the vehicle body. The door panel  34  of the tailgate apparatus is shown attached to the dump-swing hinge bracket  6 , which attaches the door panel  34  to the rear vehicle bed  49 . The upper door hinge  7  and the lower door hinge  9  are connected to the door panel  34  as shown in FIG.  1 A. The door hinge pin  8  is inserted into the lower door hinge  9 . The dump latch bar  11  is engaged with the dump latch  10 , shown in the down position. The door hinge pin holder  48  is connected to the rear vehicle bed, which also connects to the vehicle bed side wall  44 . The vehicle bed side wall  44  is attached to the front vehicle bed  46 . The dump latch release safety chain  42  is also attached to the front vehicle bed  46 ; it is shown fastened to the dump latch safety release  38 , which is connected to the dump latch  10  attached at the rear vehicle bed  49 . 
     FIG. 2B shows the door panel  34  in an open position attached to the vehicle bed side wall  44  by the safety chain  12 , which is attached at the chain fastener  40  on the vehicle bed side wall  44 . FIG. 2B also shows the dump latch safety release disengaged from the dump latch release safety chain  42 . The dump latch safety release  38  is connected to the dump latch  10 , which is in an up position and disengaged from the dump latch bar  11 . 
     FIG. 2C illustrates the door panel  34  attached to the rear vehicle bed  49  by the dump-swing hinge bracket  6 . The door hinge pin  8  is inserted into the door hinge pin holder  48  so that it is no longer hinging the door panel  34  to the rear vehicle bed  49 . The dump latch safety release  38  is disengaged from the dump latch release safety chain  42  so that the dump latch  10  is in an up position and disengaged from the dump latch bar  11  as shown in FIG.  2 B. 
     Operation 
     The tailgate apparatus has two different modes of operation. First, it can be used as a dump-style tailgate in which the door panels  34  pivot about a horizontal axis at the top of the tailgate where the door panels  34  are connected to the dump-swing hinge brackets  6 . When used as a dump-style tailgate, the door hinge pins  8  must be placed in the door hinge pin holder  48  as shown in FIG.  2 C. The door hinge pin  8  is used to connect the door panels  34  and the rear vehicle bed  49  where it is inserted in the lower door hinge  9  because the top part of the lower door hinge  9  is connected to the door panel  34 , whereas the bottom part of the lower door hinge  9  is connected to the rear vehicle bed  49 . When the door hinge pin  8  is removed from the lower door hinge  9  and placed in the door hinge pin holder  48 , the tailgate can swing about the horizontal axis at the top where the door panels  34  are connected to the dump-swing hinge bracket  6 . In addition, the dump latch  10  must be disengaged from the dump latch bar  11  by using the dump latch safety release  38  as shown in FIG.  2 C. The result is that the bottom of the door panels  34  are no longer attached to the rear vehicle bed  49  since the dump latch  10  is disengaged from the dump latch bar  11 . 
     When using the tailgate apparatus as a dump-style tailgate, the alignment locks  14  (shown in FIGS.  1 A- 1 C), the positioning fork  20 , and the positioning bracket  30  provide several different points where the door panels  34  fit together at various angles. This angular construction creates a rigid and tight fit between the door panels  34  that prevents them from buckling or collapsing while they are used as one door piece in a dump-style application. Additionally, the structure is maintained where the ratchet binder  26  can move the extension bar  24  so as to tighten the latch loops  16  around the cam locks  18  creating a tighter fit where the door panels  34  meet. The safety chains  12  may also be crossed while the door is in operation or in transit as a further precaution by fastening each chain to the chain fastener  40  attached to the opposite door panel  34  to prevent the doors from opening prematurely or from buckling. 
     Second, the tailgate apparatus can be used in split-door applications where access is need to the vehicle bed, or where the cargo load must be loaded or unloaded in a narrow or confined space. In such applications, the tailgate would appear as in FIG. 1A with the door hinge pins  8  inserted into the lower door hinges  9 , so that the door panels  34  are connected to the rear vehicle bed  49 . Again, the dump latches  10  would need to be disengaged from the dump latch bars  11  by using the dump latch safety release  38  as shown in FIGS. 2B and 2C; this allows the split door panels  34  to rotate freely about vertical axes along each side of the tailgate. 
     The split door panels  34  may be opened by ratcheting the ratchet binder  26  that in turn shortens or elongates the extension bar  24 . The extension bar  24  then moves cam actuator  25  causing the pivot bar  28  to move in a circular manner. The cam locks  18  are attached to the pivot bar  28 ; as the pivot bar  28  moves, the cam locks  18  are disengaged from the latch loops  16 . When the latch loops  16  have been disengaged from the cam locks  18 , the split door panels  34  can be fully opened as shown in FIG.  1 B. It is important to note that the off-center placement of the ratchet binder  26  protects the operator from injury upon opening the split door panels  34  because. If material in the vehicle bed shifted during transport, it could fall out unexpectedly when the door panels  34  were opened. If the operator were standing directly in front of the doors, he and other bystanders could suffer serious injuries. Since the ratchet binder  26  is placed off-center, it provides further safety precautions from such a result. FIG. 2B also shows how the split door panels  34 , once opened, can be attached to the vehicle bed side wall  44  by connecting the safety chain  12  to the chain fastener  40  that is affixed to the vehicle bed side wall  44 . 
     Conclusions, Ramifications, and Scope 
     Thus, the tailgate apparatus of this invention provides a device that can be simply operated and permits use between both dump-style and split-door style tailgate applications. The angular construction of the door panels creates a more reliable tailgate apparatus where the structure is more rigid and the split panels are more tightly fitted so that the doors do not buckle or collapse during operation of the tailgate. While my above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible. One example would be where the apparatus was used both as a dump-style tailgate and as a single door tailgate that rotates about a vertical axis at one end of the tailgate instead of both ends as described above. Accordingly, the scope of the invention should be determined not by the embodiment(s) illustrated, but by the appended claims and their legal equivalents.