Rear impact guard assembly for trailers

[0002] This application claims benefit of the filing date of Provisional application, Ser. No. 60/153,381 filed Sep. 10, 1999.

[0003] 1. Field of the Invention

[0004] This invention relates in general to cargo carrying trailers and, more particularly, to a rear impact guard assembly for a trailer.

[0005] 2. Summary of the Prior Art

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] FIG. 1 is a side elevational view of the rear impact guard assembly for trailers of the invention;

[0012] FIG. 2 is a partial end view of the rear impact guard assembly of FIG. 1 with parts broken away;

[0013] FIG. 3 is a top plan view taken along line 3—3 of FIG. 2;

[0014] FIG. 4 is a side elevational view of the rear impact guard assembly of FIG. 1 without the mounting assembly;

[0015] FIG. 5 is a top plan view of FIG. 2 taken along lines of 5—5;

[0016] FIG. 6 is top plan view of FIG. 1 without the slide rail;

[0017] FIG. 7 is a partial end view taken along lines 7—7 of FIG. 1;

[0018] 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;

[0019] FIG. 9 is a back partial perspective view of the rear impact guard assembly of FIG. 8;

[0020] FIG. 10 is a back partial perspective view with parts shown disassembled of the rear impact guard assembly of the invention;

[0021] 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

[0022] FIG. 12 is an enlarged partial perspective back view of the bumper mounting for the rear impact guard assembly of the invention.

[0023] 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 8a, and intermediate vertical section 8band lower short horizontal cross section 8c(FIG. 7). The upper horizontal section 8aof 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 10aand 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.

[0024] 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).

[0025] 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 48aand a lower horizontal plate 48bis welded to the flat plate 40 as reinforcement members. The side mounting bracket 6 further is provided with an elongated hole 42afor 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 42aof 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.

[0026] 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.