Abstract:
A work bed with its low profile load bed recessed between fenders combined with a unique tailgate mounting system is disclosed. The combination is suited for fixed or dump mounting on a truck and fixed, dump, or selective tilt or dump use on a trailer. Tailgates systems are connected to one or both work bed sides, on one or a pair if symmetrically opposite inwardly inclined axes located outboard of the sides, allowing lateral tailgates or tailgate segments to be manually pivoted to longitudinal transport positions above the fenders where they can be secured. Some tailgates also pivot about lower or upper lateral pivot axes for added versatility.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims domestic priority on U.S. Provisional Patent Application Ser. No. 61/271,314, filed Jul. 20, 2009, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to the pivotal axis of a tailgate for use on a truck or trailer bed and, more particularly, to those beds recessed between tires and fenders commonly referred to as low profile. 
     Tailgates have been designed to pivot about vertical, horizontal or combinations of these axes and all include means for locking them in a closed position. Pickup truck full width tailgates typically only pivot about a lower edge transverse axis. A low profile trailer may also have a tailgate that pivots about a lower edge transverse axis so that the tailgate can serve as a loading ramp. Enclosed low profile trailers, such as horse trailers, often have three piece tailgates with the upper portion divided into nearly equal left and right segments that each open about a vertical laterally outboard axis. They can be swung and secured in longitudinal positions above the fenders. The lower tailgate portion pivots about a horizontal lower edge axis to serve as a loading ramp. 
     Dump trailers typically have a bed that is equipped with a fixed headboard and sides about two feet in height. Selections of three alternate tailgates are often offered. A tailgate type equal in height to the sides and referred to as barn doors, divides the tailgate into nearly equal left and right segments that each open about a vertical laterally outboard axis. Another similar height tailgate can be selectively pivoted about horizontal top or bottom edge axes. When pivoted about the upper axis, chains are often used to limit the tailgate opening for spreading a load as the bed is raised while traveling forward. The same tailgate, also restrained by chains, can be selectively pivoted about a horizontal lower edge axis to align with and therefore extend the load surface rearward. Some tailgates combine the features of both of the above types. A third type, sometime referred to as a landscape tailgate, is much taller and allows selection between two lateral pivot axes. The upper axis is usually located above the elevation of the bed sides but below the top of the tailgate. This axis is supported by extended bed corner posts. The lower pivot axis is located at the lower edge of the tailgate. This tailgate functions like the preceding tailgate, except that it can be pivoted about the lower axis to act as a loading ramp or the upper axis for dumping bulky materials. A trailer equipped to selectively tilt or dump, as taught by Pat. No. RE41126, could be equipped with any of these tailgates. 
     When the beds of open trucks or trailers are empty and their tailgates are closed, transport wind resistance is increased and fuel economy suffers. When pivoted horizontal about a lateral axis, tailgates lengthen trucks or trailers and can create parking or storage issues. Transport width can&#39;t be achieved when fully opened vertical axis barn door type tailgates strike the fenders of low profile work beds. 
     It would be desirable to provide a tailgate pivot system that allowed either a full width or divided tailgate to be swing to a longitudinal position beside the bed of a truck or low profile trailer. It would also be desirable that in this position the tailgate could be secured. It would also be desired that in this position the tailgate or its support system wouldn&#39;t increase transport width. It would also be desired that in this position transport wind resistance could be reduced. It would also be desired that the same tailgate could selectively pivot about a lower lateral axis for bed extension or for use as a loading ramp. It would also be desired that, when used on a dumping bed, this tailgate could selectively pivot about an upper lateral pivot axis for spreading loose materials as the bed travels forward while being raised. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to overcome the disadvantages of the prior art by providing a pivot axis that allows the tailgate of a truck or trailer&#39;s low profile load bed to be pivoted from a transverse vertical plane to a longitudinal transport position beside the load bed. 
     It is another object of this invention to provide a mounting structure for pivoting a tailgate or tailgate segment approximately three quarters of a revolution about a non-vertical axis for transport storage above a fender. 
     It is another object of this invention to provide a pair of pivot axes that allow left and right barn door type tailgate segments to be pivoted from a transverse vertical plane to transport positions above their adjacent fenders. 
     It is a further object of this invention to provide a pivot axis that allows a full width tailgate or two axes that allow tailgate segments to be pivoted from a transverse vertical plane to a longitudinal vertical plane beside the load bed of a truck or low profile trailer. 
     It is another object of this invention that in addition to each of the above objects the tailgate support structure also accommodates lower and or upper lateral tailgate pivot axes. 
     It is a feature of this invention that tailgates can be selectively transported in their closed transverse vertical plane or in a longitudinal transport position beside the load bed. 
     It is an advantage of this invention that, when tailgates are transported in their selective longitudinal transport positions, wind resistance and fuel consumption are reduced. 
     It is another feature of the invention that full width or segmented tailgates can be secured in either their closed transverse vertical plane or in longitudinal transport positions beside the load bed. 
     It is another advantage of this invention that, when full width or segmented tailgates are secured in their longitudinal transport positions beside the load bed, some loading and unloading activities are facilitated. 
     It is another advantage of the invention that, a full width or segmented and locked together tailgate can be manually pivoted about an upper or lower lateral pivot axis and selectively restrained by pivot limiting members and the full width tailgate or each unlocked tailgate segment can be manually pivoted from its closed position to its selective longitudinal transport position. 
     It is a further object of this invention to provide a tailgate mounting support system which is durable in construction, inexpensive to manufacture, carefree of maintenance, facile in assemblage, simple and effective in use. 
     These and other objects, features and advantages are accomplished according to the instant invention by giving at least one end of the tailgate a unique outboard axis of rotation that&#39;s inclined inward or inward and rearward. The optimum orientation of this axis would be influenced by the low profile bed&#39;s fender position, shape and location relative to the lower edge of the closed tailgate. This axis allows the tailgate to be manually pivoted to and from its closed transverse vertical position to a longitudinal transport position above a fender. Including a connecting link between the tailgate and the inclined axis adds the ability to pivot the tailgate about lower and or upper axes for increased functionality. Plus, a symmetrically opposite inclined axis and connecting link, positioned on the opposite side of the bed, would allow the use of a segmented tailgate with additional versatility. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages of this invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a schematic left rear perspective view of a work bed as could be used on a truck or low profile trailer incorporating the principles of the instant invention; 
         FIG. 2  is a rear elevational view of a single axis tailgate system incorporating the principles of the instant invention. 
         FIG. 3  is a rear elevational view of a four axis segmented tailgate system incorporating the principles of the instant invention. 
         FIG. 4  is a schematic left rear perspective view of a work bed with its tailgate pivoted, about an axis inclined inward and rearward, to a vertical longitudinal plane beside the work bed and above the left fender. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the  FIGS. 1-4  the details of the truck or trailer tailgate of the instant invention can best be seen. Any reference to left, right, front or back are used as a matter of convenience and are determined by facing the normal direction of highway travel by the truck or trailer (neither shown) that would carry the work bed and its tailgate system. In  FIG. 1 , work bed  10  is configured to be suitable for use as a dump bed or a tilt and dump bed per the teaching of Pat. No. RE41126. A lateral dump pivot axis  11  is located below and near the rear of work bed  10 . While dumping a load, a lift system (not shown) would raise the front of work bed  10  while pivoting it about dump pivot axis  11 . Floor  12  defining load bed  13 , bed frame  14 , headboard  15 , left side  16  and right side  17  are the primary components of work bed  10 . Left side  16  is shown to include fender  18 , a first and second long post  19  bridging from bed frame  14  to top channel  20 , a first and second short post  21  bridging from fender  18  to top channel  20  and rear post  22  bridging from bed frame  14  to top channel  20 . Right side  17  includes like components. Attached to left side  16  rear post  22  is left support  23  for aligning lower hub  24  and upper hub  25  defining left inclined axis  26 . As shown, left inclined axis  26  reaches inward and rearward equally. The rear surface of right side  17  rear post  22  carries two U brackets  27  with their horizontal rearward reaching legs including holes to receive vertical locking pins  28  (not shown). 
       FIG. 2  shows a schematic left rear perspective view of single axis tailgate system  30  for use with work bed  10 . As with headboard  15 , left side  16  and right side  17  the top edge  31  of single axis tailgate  32  panel  33  includes a formed channel. An angle is formed at the lower edge of panel  33  reinforced by base channel  34 . Vertical channels  35  also strengthen panel  33 . The right end of panel  33  extends to the rear end of right side  17 . Pins  36  are included in single axis tailgate  32  for engagement with U brackets  27  and retention by locking pins  28  (not shown). The left end of panel  33  and base channel  34  extend past left side  16  for connection with hinge  37  and hinge pins  38  aligned for engagement with lower hub  24  and upper hub  25  on left inclined axis  26 . The inward inclination of left inclined axis  26  lifts single axis tailgate  32  above fender  18 . With an equal rearward inclination left inclined axis  26  will assure that single axis tailgate  32  attain a vertical longitudinal transport position beside the bed where it can be easily secured (not shown). 
       FIG. 3  shows four axis segmented tailgate system  40 . It differs from single axis tailgate system  30  in significant ways (The segments can separately pivot about symmetrically opposite inclined axes and together about either of the inclined axes or about two lateral axes). Four axis segmented tailgate system  40  connects to load bed  10  modified by the removal of U brackets  27  and with left support  23 , left lower hub  24 , left upper hub  25  and left inclined axis  26  symmetrically duplicated for connection with right side  17  rear post  22  creating right inclined axis  41 , right upper hub  42  (not shown), right lower hub  43  (not shown) and right support  44  (not shown). Segmented tailgate  45  includes left segment  46  and symmetrically opposite right segment  47 . Left segment  46  includes panel  48  with top and bottom edges formed the same as panel  33 , lower channel  49 , inner channel  50 , outer channel  51 , left upper pin  52  and left lower pin  53  both identical to pin  36 . Left upper pin  52  and left lower pin  53  connect with left inclined axis link  54  left U brackets  55  equivalent to work bed  10  U brackets  27  with horizontal rearward reaching legs including holes to receive vertical locking pins  56  identical to locking pins  28  (not shown). Left inclined axis link  54  includes lower hinge pin  57  and upper hinge pin  58  for engagement with lower hub  24  and upper hub  25  on inclined axis  26 . Right inclined axis link  59  symmetrically opposite to left inclined axis link  54  includes lower hinge pin  60  and upper hinge pin  61  for engagement with lower hub  43  (not shown) and upper hub  42  (not shown) on right inclined axis  41 . Right inclined axis link  59  also includes right U brackets  62  for connection with right segment  47  upper pin  63 , lower pin  64  and locking pins  65  (not shown). With left segment  46  unlocked from right segment  47 , left segment  46  is free to be manually pivoted about left inclined axis  26  and right segment  47  is free to be manually pivoted about right inclined axis  41  to longitudinal transport positions beside load bed  28  and locked (not shown). With segmented tailgate  45  closed, left segment  46  and symmetrically opposite right segment  47  can be locked together (not shown) and left segment  46  lower pin  53  aligns with right segment  47  lower pin  64  defining lower lateral axis  66  and upper pin  52  of segment  46  aligns with upper pin  63  of segment  47  to define upper lateral axis  67 . Locking pin  56  (not shown) can be removed from upper left U bracket  55  and locking pin  65  (not shown) can be removed from upper right U bracket  62  allowing segmented tailgate  45  to pivot about lower lateral axis  66  and extend the load bed or to act as a loading ramp while its rotation is limited by typical chains (not shown). Locking pin  56  (not shown) can be removed from lower left U bracket  55  and locking pin  65  (not shown) can be removed from lower right U bracket  62  allowing segmented tailgate  45  to pivot about upper lateral axis  67 , while typically restrained by chains (not shown), for spreading loose materials from load bed  13  as work bed  10  pivots about axis  11  while traveling forward. 
       FIG. 4  shows work bed  10  with single axis tailgate  32  pivoted about inclined axis  26  to its longitudinal transport position beside load bed  13  where it can be locked (not shown). Arc  70  shows the path traveled by the lower right corner of single axis tailgate  32  in moving from its closed position. The movement shown for this tailgate is typical of the inclined axis pivoting of any tailgate. 
     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiments of the invention; however, concepts as based upon the description may be employed in other embodiments without departing from the scope of the invention. For example, it should be understood that any combination of inward and rearward inclination on the inclined axis, moving the single inclined axis from the left side to the right side fall within the scope of this invention. 
     The primary purpose of a tailgate is to provide a wall to close the rear opening of a work bed and thereby secure loads. However, they can also serve to extend load beds, act as loading ramps or assist in controlling the off loading of some materials. Opening the tailgate can also facilitate loading or unloading. Many work beds have their bed frames and load beds positioned well above truck or trailer tires. This allows full width or segmented tailgates to pivot about vertical axes to longitudinal positions when opened. 
     Referring now to  FIGS. 1-4 , in  FIG. 1  a work bed with its load bed recessed between fenders (often referred to as low profile) is shown equipped with left inclined pivot axis  26 .  FIG. 2  shows single axis tailgate system  30  for pivotal connection with pivot axis  26  and closed position lock mechanism for single axis tailgate  32 . Inwardly inclined axis  26  allows tailgate  32  to selectively pivot from a closed lateral position to a longitudinal position above fender  18  where it can be locked. As shown by  FIG. 3 , left segment  46  can pivot about left inclined axis  26  and right segment  47  can pivot about right inclined axis  41 . It can also be visualized that with left segment  46  and right segment  47  locked together segmented tailgate  45  acts as a full width tailgate that, with the inclusion of left inclined axis link  54  and right inclined axis link  59 , can be pivoted about either left inclined axis  26  or right inclined axis  41 . It is also shown that with left inclined axis link  54  and right inclined axis link  59  lower lateral pivot axis  66  and upper lateral pivot axis  67  add versatility. It can be readily visualized that modifications to add left inclined axis link  54  to  FIG. 2  single axis tailgate  32  could create a three axis tailgate with the benefits provided by lower lateral pivot axis  66  and upper lateral pivot axis  67 . Further, it can be visualized that such a tailgate could extend well above upper lateral pivot axis  67 . With lengthened rear posts and the addition of an elevated third lateral axis for selective attachment, this tailgate could serve as a landscape tailgate within the scope of the instant invention.