Abstract:
A rear impact guard assembly for trailers for absorbing the energy of a rear impact from another vehicle including a pair of tubular vertical guards having a lower tubular horizontal tube mounted at their lower ends. The upper ends of the vertical guards are attached to a horizontal beam, which in turn is affixed to longitudinally extending side rails. The vertical guards are removably affixed to the horizontal beam and respectively removable affixed to the slide rails. Tubular members extend through holes

Description:
This application claims benefit of the filing date of Provisional application, Ser. No. 60/153,381 filed Sep. 10, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates in general to cargo carrying trailers and, more particularly, to a rear impact guard assembly for a trailer. 
     2. Summary of the Prior Art 
     Cargo carrying trailers for highway use are commonly elevated from the highway. As a result, it is known that automobiles and other vehicles commonly impact underneath the back structure of a trailer during rear collisions causing possible serious injury and damage to the colliding vehicles. In order to reduce the damage caused by rear collisions of trailers, recent federal regulations have been introduced requiring the presence of impact guards having defined strength characteristics to reduce both injury and damage. For example, impact guards for trailers must withstand certain minimum impact forces and to absorb energy from impact within  5  inches of plastic deformation of the impact guard as a result of collisions up to thirty miles per hour. Many known techniques for reducing damage due to rear collisions of trailers employ relatively heavy components, which do not provide optimum protection and economy of assembly and repair. With prior rear protection, damage to the structural components of the trailer as a result of rear collisions can also occur. These damaged structural components require costly and time-consuming repair in order to restore the trailer to a safe operating condition. 
     In the past, damaged trailers sometimes are operated with severely deformed rear components, such as bumpers, guards and the like. By being operated in such a damaged state, rear impact protection may be compromised because of which federal regulations are being considered to require the replacement of all severely deformed rear impact guards. To replace damaged rear guards, previous impact guard systems require expensive replacement and repair in order to restore the components to an optimally safe, undamaged condition. 
     Previous designs of impact guards further do not provide an optimally economical replacement after a trailer is subjected to a rear collision. Accordingly, it is desirable in the prior art to provide an improved impact guard assembly to be used at the rear of a trailer body to absorb the energy of rear impact without significant damage to the trailer structure. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an objective of the invention to provide an improved impact guard assembly to minimize injury and damage occurring as a result of impact against the rear of a trailer body by an automobile and the like. The impact guard assembly herein disclosed includes a plurality of vertical guards and a horizontal bumper which assembly is suitably affixed for removal to the rear of the trailer. The impact guard of the invention exceeds applicable standards regarding the absorption of impact forces as prescribed by federal law. After impact the assembly herein disclosed undergoes permanent plastic deformation and may be readily replaced by an undamaged impact assembly by removal of bolts or attachment techniques. The effectiveness of the absorption of energy insures that the components of the trailer frame on which the impact guard is removably mounted are not subjected to potential damaging deformation under a large range of impact conditions. Accordingly, the invention effectively isolates the major structural components from the damaging effects of rear collisions. By protecting the major trailer components, the costs and time required for repair are greatly reduced by the invention. 
     The design of the rear guard assembly herein provides a lightweight structure, which is economical to manufacture because of open sections and less parts. The rear guard assembly further provides a controlled and predictable deformation as a result of impact. Ease of assembly and disassembly for repair is facilitated by convenient bolted or riveted attachment of guard assembly to the trailer frame. The rear guard assembly herein not only is affixed to the rear sill, but also to the trailer slider rails for transfer of the loads imposed by impact to provide under a structure with improved strength. The invention provides an effective technique of preventing injury and minimizing damage to a colliding vehicle and to the trailer structure apart from the rear impact assembly as compared to prior art, rear protection techniques. In addition, the rear impact assembly herein disclosed may be readily removed even in a deformed state and replaced by a new assembly for economy and convenience allowing an impacted trailer to quickly return to service. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of the rear impact guard assembly for trailers of the invention; 
     FIG. 2 is a partial end view of the rear impact guard assembly of FIG. 1 with parts broken away; 
     FIG. 3 is a top plan view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a side elevational view of the rear impact guard assembly of FIG. 1 without the mounting assembly; 
     FIG. 5 is a top plan view of FIG. 2 taken along lines of  5 — 5 ; 
     FIG. 6 is top plan view of FIG. 1 without the slide rail; 
     FIG. 7 is a partial end view taken along lines  7 — 7  of FIG. 1; 
     FIG. 8 is a partial front perspective view of the rear impact guard assembly of the invention shown mounted on the rear frame of a trailer; 
     FIG. 9 is a back partial perspective view of the rear impact guard assembly of FIG. 8; 
     FIG. 10 is a back partial perspective view with parts shown disassembled of the rear impact guard assembly of the invention; 
     FIG. 11 is a side perspective view of the mounting of the cross tubes of the side of the rear impact guard assembly of FIG. 8; and 
     FIG. 12 is an enlarged partial perspective back view of the bumper mounting for the rear impact guard assembly of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1-12, there is illustrated the rear impact guard assembly of the invention for trailers being generally designated by reference numeral  2  and formed from a suitable metal and the like. The rear impact guard assembly  2  is provided with a pair of vertical guards  4  and a side mounting bracket assembly  6  as seen in FIGS. 1,  6  and  10 . A respective side mounting bracket assembly  6  supports each of the vertical guards  4  in attached relationship thereto and to a longitudinally extending slide rail  8  in a manner to be described. The slide rail  8  is conventionally used in trailers and possesses a cross-sectional shape having a top horizontal section  8   a , and intermediate vertical section  8   b  and lower short horizontal cross section  8   c  (FIG.  7 ). The upper horizontal section  8   a  of the slide rail is affixed to the conventional structural cross I-beams  9  on the underside frame and the rear door frame of the trailer body as shown in FIGS. 1 and 8. The lower end of the vertical guard  4  is affixed by welding or bolts (not shown) to the rear cross guard member  10  of the rear impact guard assembly  2 . The cross guard member  10  in the form a tubular structure and has free ends  10   a  and is supported by the vertical guards  4 . Alternatively, the horizontal cross guard  10  may be otherwise affixed to a vertical post or other member (not shown) of the trailer body. As best shown in FIGS. 8 and 10 the pair of vertical guards  4  are secured at the upper end to the rear sill  11  of the trailer as will be described. The rear sill  11  is connected to the conventional major structural underframe of the trailer. 
     Details of the vertical guard  2  are best shown in FIGS. 1-5. Although two vertical guards  4  are shown utilized in connection with the invention (FIG.  2 ), it is within the scope of the invention to use other number of vertical guards as is appropriate under given circumstances. Each of the vertical guards  4  are fabricated with a modified U-shaped cross section having an intermediate wall  12  facing rearward from the trailer, an elongated side flange  14  and a shorter opposed side flange  16  whereby the vertical guard  4  is open at its rear facing the front of the trailer and at its top and bottom. As best seen in FIGS. 2,  4 , and  5 , the elongated flange  14  of the vertical guard  4  includes a reinforcement flange  18  which serves as an additional stiffener to flange  14 . Each vertical guard  4  is provided with a pair of horizontal gussets  20  which are respectively welded to side flanges  14  and  16 , and front wall  12  of the vertical guard  4 . Although two gussets  20  are shown, it is within the scope of the invention to use one or more than two gussets if desired. Under impact forces, the vertical guards  4  are subjected normally to torsional loading to cause the vertical guards  4  to undergo plastic deformation in a controlled manner. Control of the deformation of the vertical guard  4  is achieved by the transfer of loading and bending by gussets  20  between the flanges  14  and  16  and because of the presence of reinforcement flange  18 . The combined effect of gussets  20  and reinforcement flange  18  serves to insure that deformation of the vertical guards  4  due to excessive impact forces commences at the gussets  20  to result in predictable deformation of the vertical guards for superior control of impact forces. It is an important function of the vertical guards  4  along with horizontal member  10  to not only absorb the forces of impact in a range exceeding federal regulations, but to insure that damaging deformation forces are not transferred to slide rails and the underframe of the trailer through rear sill  11 . The flange  14  includes a pair of upper bracket securement holes  22  (FIGS.  1  and  10 ). The vertical guard  4  further has an upper mounting attachment hole  24  (FIG. 1) disposed through front wall  12  for attachment to the trailer intermediate cross member  11  at its upper position (FIGS.  1  and  6 ). 
     As is best seen in FIGS. 8,  9 ,  10 , and  12 , the mounting of the upper portion of the vertical guard  4  is accomplished through use of a U-shaped channel weldment  30  which is welded to the underside of the rear sill  11  of the trailer. The weldment  30  has a cross sectional configuration in shape allowing it to telescope snugly within the top of the vertical guard  4  whereby a bolt assembly  32  (FIGS.  1 , 6 , and  8 ) affixes the vertical guard  4  to the weldment  30  and hence to the intermediate cross member  11 . The side mounting bracket  6  includes a vertical plate  40  as seen in FIGS. 1,  6 ,  7 ,  10 , and  11 . The inside end of the side mounting bracket  6  includes a curvilinear upper portion  42  having a shape corresponding to a segment of one of the conventional holes  44  provided in the slide rail  8 . The lower portion  46  of the side mounting bracket  6  is angularly cutoff whereas the remainder of the edges bottom, top and front edges of the side mounting bracket  6  are straight. A U-shaped section  48  having a pair of vertical plates  48   a  and a lower horizontal plate  48   b  is welded to the flat plate  40  as reinforcement members. The side mounting bracket  6  further is provided with an elongated hole  42   a  for each slide rail  8 . A channel/cross-member reinforcement  50  having a modified U-shape is suitably attached by welding and the like to the side of the rear sill  11  as best seen in FIGS. 9,  10  and  12  and includes a projecting attachment pin  52 . The pin  52  not only facilitates assembly/disassembly of the rear bumper guard assembly  2 , but transfers impact loads to the rear sill  11  and out to the trailer bottom outer rails (not shown) without deformation of the slider rails  8 . Channel  50  further reinforces the rear sill and transmits excessive torsional loads to the rear sill  11  through pin  52  and to the bottom outer rails (not shown). The channel  50  reinforces the flanges of the cross-member against deformation for forces not absorbed by rear guard assembly  2  and are transmitted to the rear sill and the outer bottom rails. The pair of slide rails  8  are provided with a vertical end plate  54  having suitable holes  56  such that the pins  52  are inserted in the slide end rail plate  54  for support. A bolt assembly (not shown) also attaches the plate  54  to the channel  50  through hole  53  (FIG.  9 ). A pair of cross-tubular member  58  extend between the pair of slide rails  8  and have end portions projecting through aligned pairs of holes  44 . The end portion of one of the tubular members  58  also extends through elongated hole  42   a  of bracket  6  while the interior tubular member  58  extends through slide rail hole  44  disposed adjacent to the upper curvilinear section  42  of plate  40  of the side bracket assembly  6 . Conventionally, the holes in the slide rails may be spaced by different center spacings. Thus, elongated hole  42  permits universal mounting of the assembly under different center spacings. The structure of the tubular members  58  and the side mounting bracket assembly aid in strengthening the trailer sub-frame and slide rails preventing torsional impact forces to damage said rails. 
     Under impact conditions, the vertical guards  4  and cross guard  10  demonstrate physical strength characteristics to absorb energy of impact within  5  inches of permanent deformation under conditions prescribed by law. After deformations of guard components occur, each of the vertical guards  4  and horizontal guard  10  so damaged may be readily removed as a unit through removal of bolts  32  and  60 . The side bracket assembly  6  can also be replaced if necessary. In certain situations, it is also possible to remove vertical guard  4  separately from horizontal guard  10  under situations in which separation between the lower end of vertical guards  4  and lower horizontal guard  10  can be separated such as, for example, the vertical guard  4  and guard  10  being interconnected by bolt assemblies or other means permitting separation of the parts. Upon removal of the damaged components, a replacement guard assembly can easily be accomplished by reinsertion of the bolt assemblies. The deformation of the impact guard assembly  2  not only minimizes damage to the colliding vehicle, but also alleviates structural damage to the trailer.