Abstract:
A system for supporting the bed of a utility vehicle, the system adapted to be mounted on the underbody frame of the utility vehicle, the system comprising: a generally planar unitary support formed from a composite material, the support having a first surface and a second vertically offset surface; a plurality of connecting members extending from the first surface to the offset surface, the members providing strength to said support; a generally rectangular panel fabricated from a composite material, the panel adhesively attached to said offset surface, the panel adapted to serve as a loading surface for the bed of the utility vehicle; a bracket secured to the support for mounting the support to the frame of the utility vehicle; and a backing plate secured to the support, wherein the plate and the bracket sandwich the support to secure it to the frame of the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional patent application Ser. No. 61/942,726, filed Feb. 21, 2014, under 35 U.S.C. §119(e). 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to support structures located underneath the shell or body of a vehicle. More specifically, it relates to corrugated support structures formed of composite material located below the bed of a utility vehicle. 
     Background &amp; Description of the Related Art 
     It is common for public works departments, contractors and service companies to send workers into the field to provide on-site services at remote locations. To perform these services, technicians must usually take tools or materials with them to the job site. One way to transport such items is to load them on a utility vehicle and drive the vehicle to the job site. Typically, these utility vehicles are truck type motor vehicles comprising multiple storage compartments and a bed area for receiving cargo. The vehicles may include an aerial lift or equipment tower to reach elevated locations. The vehicles are designed to maximize storage space on the vehicle while allowing transportation of large, heavy tools that may not be suitably transported by other vehicles. 
     Furthermore, these utility vehicles are often operated in a harsh and demanding manner. It is not uncommon for heavy tools to be tossed or dropped into the bed of the vehicle. Repeated impact from heavy tools or cargo can damage a bed that is not properly supported. The terrain on which the utility vehicles are driven can be rugged which causes bouncing and shifting of heavy cargo in the bed. These utility vehicles may be used in severe weather such as extreme temperatures, precipitation and high winds. For these reasons, these utility vehicles must be structurally robust and durable. 
     To help improve durability and strength, many utility vehicles incorporate a support structure located beneath the bed of the vehicle. This support structure is commonly referred to as an understructure. The understructure helps to support and reinforce the bed as it encounters heavy loads and repeated impact from cargo. The understructure also helps support the vehicle&#39;s body which usually includes numerous racks and utility compartments. 
     Traditional understructures comprise steel or aluminum tube members welded together in a rectangular configuration. The understructure typically has mounting brackets along its perimeter which are used to bolt the understructure to a vehicle frame. Although a traditional metal understructure provides a sturdy support system, it has certain drawbacks. First, the understructure adds significant weight to the vehicle due to its heavy metal construction. The added weight can impact gas mileage and longevity of the vehicle&#39;s suspension system. Second, a traditional metal understructure is highly susceptible to corrosion due to environmental conditions. Water, salt, and other chemicals found on roadways tend to splash onto metal understructures and lead to rust or other corrosion. 
     What is needed in the industry is an understructure that provides the strength and durability of a traditional metal understructure without the weight and corrosion issues mentioned above. As is discussed below, the present invention addresses this need. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a composite understructure and bed for a utility vehicle which may be used on all types of utility vehicles including those having an aerial tower. The understructure is generally planar with a unique arrangement of corrugations and elevated surfaces that help to strengthen and stiffen the understructure. The corrugations create vertical segments, or walls, that act as strengtheners for the understructure. A floor plate, which forms the loading surface of the bed of the vehicle, can be attached over the top of the understructure. The floor plate and understructure together form a bed support assembly. The understructure may have cut-outs to accommodate an aerial tower or access a fuel tank. The understructure may also have cut-outs between its stiffening walls to reduce its weight. The understructure and floor plate are preferably formed from a fiber reinforced composite material such as fiberglass formed from glass fibers and a thermoset resin. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a utility vehicle having an aerial tower. 
         FIG. 2  is an exploded perspective view of the rear cargo area of the utility vehicle of  FIG. 1 , showing a first embodiment of the understructure in accordance with the present invention. 
         FIG. 3  is a perspective view of the composite understructure of  FIG. 2 . 
         FIG. 4  is a cross-sectional view of the bed of the utility vehicle taken along line  4 - 4  of  FIG. 1 . 
         FIG. 5  is a cross-sectional view of the composite understructure taken along line  5 - 5  of  FIG. 3 . 
         FIG. 6  is a perspective view of a second embodiment of a utility vehicle which does not include an aerial tower. 
         FIG. 7  is an exploded perspective view of the rear cargo area of the utility vehicle of  FIG. 6 , showing a second embodiment of the understructure in accordance with the present invention. 
         FIG. 8  is a perspective view of the composite understructure of  FIG. 7 . 
         FIG. 9  is a cross-sectional view of the bed of the utility vehicle taken along line  9 - 9  of  FIG. 6 . 
         FIG. 10  is a cross-sectional view of the composite understructure taken along line  10 - 10  of  FIG. 8 . 
         FIG. 11  is an enlarged fragmentary, exploded view of a mounting bracket for either the first or second embodiments of the understructure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
     Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words “upwardly,” “downwardly,” “rightwardly,” “leftwardly,” “upper,” and “lower” will refer to the installed position (as shown in the drawings) of the item to which the reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the embodiment being described and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof and words of a similar import. 
     The invention comprises a bed support assembly. The assembly includes a vehicle bed plate which presents a loading surface secured over the top of a corrugated understructure formed of composite material such as fiber reinforced polymer or fiberglass, mounted by a series of brackets to the vehicle&#39;s frame.  FIGS. 1-5 and 11  show a first embodiment of the invention employed with a utility truck  6  having an aerial tower  3 , and  FIGS. 6-10  show a second embodiment of the invention as used with a flatbed utility vehicle  206 . The first embodiment of the bed support assembly  24  accommodates the truck&#39;s aerial tower  3  and the fuel tank  4  while the second embodiment of the bed support assembly  224 , used with the flatbed truck  206 , does not. The bed support assemblies  24  and  224  each include a bed or floor plate  22  or  222  which forms a loading surface, secured over a corrugated, generally planar understructure  5  or  205  which is secured to a vehicle&#39;s frame by a series of brackets  59 ,  60 ,  61 . 
     Now, the first embodiment, bed support assembly  24 , will be discussed in detail. As best seen in  FIGS. 2 and 4 , the understructure  5  is installed beneath the rear cargo area or bed  10  of utility vehicle  6 . The bed  10  is defined by the floor plate  22 , side walls  31 , and a front wall  33 . In some situations, bed  10  may also comprise a rear gate but the gate is not required or shown. Side walls  31  are often formed from the back walls of utility compartments  34  which are installed along the sides of the bed  10 . Utility compartments  34  are used for storage of the smaller tools and materials transported on the utility vehicle  6 . The utility compartments  34  are generally configured such that their doors  38  open away from the bed  10 . It is foreseen that certain utility vehicles  6  may not include utility compartments  34  or the compartments may not be along the sides of bed  10  in which case side walls  31  will not be formed from the back walls of the compartments. It is also foreseen that on certain vehicles, bed  10  may not include any side walls  31  or a front wall  33 . A bed  10  without any walls would be defined only by the periphery of floor plate  22 . 
     The understructure  5 , as seen in  FIG. 3 , is a generally rectangular platform having a front edge  40 , side edges  41 , and back edge  42 . Because the understructure  5  is fabricated from composite material, it is lighter and more resistant to corrosion than conventional metal understructures. 
     The understructure  5  is corrugated to include a unique arrangement of raised areas or ridges  20 . Each ridge  20  extends upwardly from the surface  43  of the understructure  5  and is formed by a generally vertically extending projection, connecting member or wall  44  that extends transverse to the plane of the surface  43  of the understructure  5 . Each wall  44  adds strength and stiffness to the understructure  5  to help minimize flexing and increase strength when the understructure  5  is exposed to transverse or bending forces acting perpendicular to the plane of the understructure  5  (e.g., when cargo is placed in bed  10 ). The ridges  20  each extend the same distance from the surface  43  with a plateaued configuration, or a flat top, to form to top surface of the understructure  5 . Alternatively, the ridges  20  could extend downwardly from the surface  43  to present grooves. Still yet, the understructure  5  could be formed with a combination of ridges and grooves. 
     Each wall  44  is more resistant to flexing than the planar surface  43  of the understructure  5  when a force acts perpendicular to the plane of the understructure  5 . This is due in part to the differences between the area moments of inertia of the cross-sections of the planar surface  43  and the walls  44 . The cross-sections of the walls  44  have a larger area moment of inertia than the cross-sections of the planar surface  43  with respect to a perpendicular or transverse force. The difference in area moments of inertia is primarily due to the vertical orientation of the walls  44  compared to the horizontal orientation of the planar surface  43 . 
     The shape and layout of the raised areas  20  may vary based on the physical characteristics of understructure  5  and its anticipated use. For example, certain layouts may perform better than others for different types of composite materials. Layouts may also vary depending on the desired size, weight or use of the truck  6 . As shown in  FIGS. 2 and 3 , a preferred layout for raised areas  20  includes walls  44  which run diagonally or crosswise with respect to the rectangular shape of understructure  5 . In other words, at least one of the walls  44  is oriented at an angle across the understructure  5  so the wall is neither parallel nor perpendicular to any of the edges of understructure  5 . The “X” shaped wall pattern perform particularly well because such pattern adds strength and stiffness to the understructure  5  while still permitting some flexing to prevent cracking. 
     The raised areas  20  on the understructure  5  are typically mirrored about a longitudinal axis, axis A-A as shown in  FIG. 3 , running from the midpoint of front edge  40  to the midpoint of back edge  42 . That is, for each area that is raised on one side of the longitudinal axis, there is a corresponding area mirrored on the opposite side of the axis that is similarly raised. Accordingly, the walls  44  are also mirrored about the longitudinal axis. While a mirrored configuration appears to be most effective for improving strength and stiffness of understructure  5 , it is foreseen that certain non-mirrored arrangements could also be effective. 
     The understructure  5  is attached to utility vehicle  6  using brackets  59 ,  60 ,  61  which are shown in  FIGS. 3, 4 and 11 . The brackets  59 ,  60 ,  61  are secured to the understructure  5  prior to the understructure  5  being secured to floor plate  22 . As seen in  FIGS. 3 and 4 , the front brackets  59  are located at the front corners of the understructure  5  and the rear brackets  61  are at the rear corners. The middle brackets  60  are located along the sides of the understructure  5  between the front brackets  59  and rear brackets  61 . As best shown in  FIG. 11 , each front bracket  59  comprises an L-shaped upper support  62  attached to an L-shaped base  65 . The upper support  62  forms a slightly obtuse angle but alternatively it could form a right angle. The upper support  62  receives a front portion of the side wall  44  that is proximate a side edge  41  of the understructure. The side wall  44  engages the inner surface of the vertically extending flange  71  of the upper support  62  such that the understructure&#39;s surface  43  rests on the horizontal flange or leg  70  of the support  62  and an outer surface of the side wall  44  contacts an angled vertical flange or leg  71  of the support  62 . 
     The horizontal leg  70  and vertical leg  71  each have holes for receiving a threaded fastener  73  such as a bolt therethrough. Corresponding holes are drilled through the side wall  44  and the surface  43  to align with the holes in the horizontal leg  70  and vertical leg  71 . Threaded fasteners  73  are inserted through the holes and secured against a back plate  75  using threaded nuts or the like. The back plate  75  has an angled configuration similar to upper support  62  and the plate is positioned on the inner surface of side wall  44  and the surface  43 . When the threaded fasteners  73  are tightened, the bracket  59  is securely attached to the understructure  5  by sandwiching it between the back plate  75  and the upper support  62 . It is foreseen that a middle bracket  60  could share a back plate with either a front bracket  59  or back bracket  61  if the middle bracket is proximate either of those brackets. 
     The understructure  5  is attached to the vehicle frame  56  by securing the front, middle and back brackets  59 ,  60 ,  61  to the frame  56 . As best seen in  FIGS. 4 and 11 , threaded fasteners  78  such as bolts are used to secure the brackets  59 ,  60 ,  61  to the vehicle frame  56 . The base  65  of the bracket  59  generally forms a right angle to include a horizontal mounting plate  80  that contacts the frame  56 . There is at least one hole in each mounting plate  80  for receiving a threaded fastener  78 . Depending on the size of the understructure  5 , the mounting plates  80  for the bracket  59  could have multiple holes and utilize multiple threaded fasteners to hold the understructure to the frame  56 . To secure the understructure  5  to frame  56 , the holes in the mounting plates  80  are aligned with corresponding holes in the frame  56  and threaded fasteners  78  are inserted therethrough. Threaded fasteners  78  are tightened using threaded nuts or the like, thus securing the understructure  5  to the vehicle frame  56 . It should be understood that although bracket  59  is discussed in detail, brackets  60  and  61  secure the understructure  5  to the frame  56  in a similar fashion. 
     It is foreseen that various hardware could be used with the threaded fasteners  78  such as washers and lock washers when connecting the understructure  5  to the frame  56 . In some installations it may be beneficial to use a spring bolt connection as shown in  FIG. 11 . With such a connection, the bolt  78  is inserted through a spring  79  before the bolt  78  is inserted through the holes in the mounting plate  80  and frame  56 . The spring is sandwiched between two washers and located on top of the mounting plate  80  which is on top of frame  56 . For a spring bolt connection, the bolt  78  is partially tightened to secure the mounting plate  80  to frame  56 , but not tightened to the point of fully compressing the spring. A spring bolt connection allows the frame  56  to temporarily separate from mounting plate  80  by compressing the spring for shock absorption purposes. 
     Preferably, six brackets  59 ,  60 ,  61  secure the understructure  5  to the vehicle frame  56  (a front  59 , middle  60  and back  61  bracket on each side of the understructure  5  with each pair being aligned). However, it is foreseen that the number and type of brackets could vary. For example, a large understructure might require more middle brackets or a small understructure may not require any middle brackets. Also, there could be brackets located away from the edges of the understructure such as toward the center of the understructure. It is also foreseeable that brackets could be located along the front and back edges of the understructure depending on the configuration of the vehicle frame. 
     Understructure  5  has openings  83  and  92  formed therein to allow installation of an aerial lift or tower  3  and access to the fuel tank  4 , as seen in  FIGS. 2 and 3 . The aerial tower opening  83  is square shaped and sized to allow the base  86  of the aerial tower  3  to extend through the opening  83 . The aerial tower  3  typically attaches directly to the frame  56  of the utility vehicle  6  and projects above the understructure  5  and is stored in or above the bed  10  of the vehicle. The aerial tower or lift  3  may have a basket for holding a worker or some other device attached to the distal end of the tower. When the tower  3  and the understructure  5  are installed, the understructure  5  is configured such that the base  86  extends up through opening  83  with only a small gap  88  between the perimeter  89  of opening  83  and base  86 . The gap  88  is large enough to allow vibrations and some movement by base  86  (for example when tower  3  is supporting a load or when the vehicle is in motion) without the base contacting the understructure  5 . The gap  88  is small enough to prevent tools and other items from falling into the gap and potentially onto the ground under vehicle  6 . In this embodiment, the aerial tower opening  83  is generally located toward the front of the understructure  5  and centered along longitudinal axis A-A. It is foreseen that other shapes, sizes and locations can be used for the aerial tower opening  83 . 
     The understructure  5  also has an opening  92  to allow access to fuel tank  4 . Fuel tank access opening  92  is square shaped and positioned above the primary inlet  95  to the fuel tank  4 . Generally, fuel tank  4  has a fuel pump assembly and sensors located within the tank and those components are usually installed through the fuel tank inlet  95 . Fuel tank access opening  92  allows convenient access to these components. The fuel tank access opening  92  is large enough to allow access to the components for maintenance or repair so that the bed support assembly  24  and tank  4  need not be removed from vehicle  6  during maintenance. The size and location of fuel tank access opening  92  will depend on the size and configuration of fuel tank  4  and inlet  95 . In this embodiment, the opening  92  is generally located on the back half of the understructure  5  and centered along longitudinal axis A-A. Fuel tank  4  is typically not filled with fuel through opening  92  as there is a specific fuel fill cup on the back of the vehicle  6  to receive a filling station nozzle. 
     As best seen in  FIGS. 2 and 3 , the understructure  5  also has several circular openings  98  which receive tie-down rings or anchors (not shown). The anchors are used to secure cargo in the bed  10 . The anchor ring openings  98  are approximately three inches in diameter and able to receive a plug or bracket to which an anchor ring can be secured. For heavy duty applications, an anchor ring could be attached directly to the vehicle frame  56  and extend through openings  98  rather than attaching to the understructure. In this embodiment, the understructure  5  has four anchor ring openings  98 ; however, it is foreseen that an understructure may have any number of openings  98 . 
     The floor plate  22  is secured over the top surface of the understructure  5 . Floor plate  22  serves as the loading surface of the bed. As best seen in  FIGS. 2 and 7 , the floor plate  22  is substantially rectangular with two upwardly turned side flanges  107  along its longitudinal perimeter. The side flanges  107  extend along the length of the plate  22  and extend upwardly therefrom from approximately and preferably three inches. The upwardly turned side flanges  107  are attached to the bed side walls  31 . The floor plate  22  also has two end flanges  108  which extend along the plate&#39;s front and back edges. The end flanges  108  extend downwardly approximately six inches from the front and back edges of the plate  22 . 
     Floor plate  22  has openings that correspond to the size, shape and location of certain openings the in understructure  5 . For example, floor plate  22  has an opening  106  which corresponds to aerial tower opening  83 , an opening  110  which corresponds to fuel tank access opening  92 , and openings  112  which correspond to anchor ring openings  98 . The floor plate  22  openings align with the understructure  5  openings when the floor plate and understructure are adhered together. A removable access door  109  covers the fuel tank opening  110  in floor plate  22 . Access door  109  may be hinged or completely removable and has a mechanism for locking the door when closed. Also, the anchor ring openings  112  in floor plate  22  may have a plug or bracket to which an anchor ring can be secured. It is foreseen that floor plate  22  could use sizes and shapes for its openings that are different than the sizes and shapes of the openings in understructure  5 . Floor plate  22  would typically not have openings corresponding to openings  101  of understructure  100  which are primarily for reducing the weight of an understructure. 
     The floor plate  22  attaches over the top of the understructure  5  to form the bed support assembly  24 . Floor plate  22  is attached to the understructure using a high strength adhesive  111  designed for bonding composite materials. One example of a manufacturer that makes such adhesives is ITW Plexus®. To attach floor plate  22  to understructure  5 , the high strength adhesive  111  is applied to the surface of the raised areas  20  on understructure  5  and then floor plate  22  is placed over the adhesive coated ridges  20 . Accordingly, the bottom surface of the floor plate  22  bonds to the top surface of the raised areas  20 . The adhesive is allowed to cure which fixedly bonds the floor plate  22  to understructure  5 . 
     The components forming the bed, including the understructure  5 , floor plate  22 , side walls  31 , front wall  33  and utility compartments  34  are preferably formed from a fiber reinforced resin composite material such as fiberglass and can be formed using a process called resin transfer molding (RTM). The RTM process involves placing mats or sheets of woven fibers in a mold, closing the mold, injecting resin into the mold until substantially all of the air in the mold has been displaced by resin and then allowing the resin to cure or polymerize (heat may be added if necessary to facilitate curing). After the resin has cured, understructure  5  is removed from the mold and trimmed, sanded, or polished as necessary to create the final product. Commonly used fibers are glass or carbon, and a resin that may be used is vinyl ester. It is foreseen that other materials or processes for forming a fiber reinforced composite material can also be used to create understructure  5 . 
     Now, with regard to the second embodiment shown in  FIGS. 6-10 , only the differences between and distinctions from the first embodiment will be discussed in detail. The understructure  205  of the second embodiment, as best seen in  FIGS. 7 and 8 , does not have an aerial tower opening and may or may not have fuel tank access openings or anchor ring openings. The understructure  205  includes cut-outs  250  in many of the ridges  220  framed by walls  244  which extend upwardly from the understructure&#39;s surface  243 . The openings  250  are formed in the planar or plateaued flat portion of the raised areas  220 . A rim  246  forms the periphery of each cut-out  250  and extends inwardly from the corresponding wall  244 . Cut-out openings  250  are beneficial because they reduce the weight of the understructure  205  as well as allow access to items installed below the understructure  205 . While cut-outs  205  are shown and described in connection with this embodiment, it is foreseen that such cut-outs could also be used in connection with the first embodiment. 
     It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.