Patent Publication Number: US-2006006023-A1

Title: Combination rear impact guard, ladder, and ramp for military cargo vehicles

Description:
GOVERNMENT INTEREST  
      The invention described herein may be made, used, and licensed by, or for, the United States Government for governmental purposes without paying me any royalty. 
    
    
     BACKGROUND AND SUMMARY  
      This invention relates to a multifunctional structure to be vertically mounted on the rear of military cargo vehicles, such as tactical trucks, trailers, and semi-trailers. In a first aspect, the invention in a retracted or closed position acts as a rear-impact guard to avoid rear-end crashes by trailing motor vehicles with the bed, its underside, and/or the running gear. In another aspect, the same structure when partially extended will give soldiers a ladder structure to facilitate their ingress and egress of the rear bed. In a separate aspect, a ramp is easily provided when said structure is fully extended to load and unload cargo aboard the vehicle.  
      Thus, military cargo vehicles are used by armed forces for the transport over long distances of heavy military equipment, ammunition, fuels, water, rations, troops, and related support cargos within a theater of operations. These activities often require a variety of both medium- and heavy-duty vehicles that operate within less than optimal environments, including on- and off-road conditions, for support of our global peacekeeping and warfighting efforts.  
      As used herein, a typical cargo vehicle is chosen from a Family of Medium Tactical Vehicles (FMTVs), that are produced by Stewart &amp; Stevenson of Houston, Tex., USA. These trucks are available in a number of variants with load capabilities ranging between 2.5 to 10 tons. The subject trucks and trailers may, or may not, have tailgates or doors across the horizontal rear end of the bed. These gates and doors may be fashioned of a hard material or they may be made in the form of a web of natural or synthetic fibers and coatings or composites thereof.  
      It is understood that the readiness requirements for these vehicles are highly unusual, and therefore necessitate more rigorous and reliable designs than their commercial counterparts. The components of these vehicles, including the bed, supporting elements, and associated equipment, must tolerate more frequent vibrations and impacts than their commercial counterparts. These requirements are even greater when military personnel are aboard.  
      Normally, the beds of cargo vehicles are disposed some vertical distance, typically up to about 5 feet, above the surface over which they are traveling. The result of this configuration is that the beds are substantially horizontal and overhang the running gear or wheels by a considerable distance. For over the road applications, this high vertical alignment can present potential problems for any trailing vehicle of lower height than the bed overhang. Since an operator of a trailing vehicle may become distracted while driving, it is possible that the trailing vehicle might strike the cargo vehicle and submarine below the bed. Reference is made to  FIGS. 1 and 2  for clearer understanding of this potential.  
      The likely result of such an accident would be sustainment of substantial damages and injuries to both passengers and vehicles. As used herein, a trailing vehicle includes trucks, cars, vans, and sport utility vehicles of a variety of shapes and sizes. As a result, it is very desirable to equip our military cargo vehicles with rear impact protection, or under-ride prevention, for highway travel. Moreover, a host of motor carrier safety standards have been set by state and federal regulatory agencies to mandate the addition of protective devices for trucks and trailers to avoid or ameliorate the potential for accidents. See, for example, 49 Code of Federal Regulations 571.223 and .224.  
      Moreover, the bed height of military cargo vehicles makes it quite difficult for a soldier to enter or embark from the elongated, horizontal bed without some means of assistance. This problem is further compounded by the fact that soldiers must carry battle gear on them which can weigh somewhere in the neighborhood of 60 to 100 pounds. This gear is also quite bulky and is rarely distributed evenly about the body. These factors negatively affect balance and place the solider at substantial risk during entry or exit of a vehicle bed without a more practical form of support and assistance.  
      These and other objects, features, and advantages of this invention will be apparent to those skilled in the relevant arts upon a full reading of this specification and the appended claims which explain and define the aspects and principals of this invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a fragmentary rear view of a military cargo vehicle of the prior art.  
       FIG. 2  is a side view of the vehicle of  FIG. 1 .  
       FIG. 3  is a side view of a military cargo vehicle with my invention installed in a retracted position as a rear impact guard that horizontally extends across the rear end.  
       FIG. 4  is a separate side view depiction of my invention secured across a rear bed of a military cargo vehicle and deployed therein as a set of supporting stairs for troop exit or entry of said vehicle.  
       FIG. 5  is another side view of my invention where it is mounted across a rear bed of a military cargo vehicle as a platform and/or ramp to accomplish loading and unloading operations. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  depicts a military cargo vehicle  10  of the prior art in fragmentary rear view. It is to be understood that our military interchangeably uses a variety of trucks and trailers for the purposes of supporting units that are engaged in a variety of war fighting or peacekeeping operations. Cargo vehicles have highly unusual usage requirements for the rapid deployment of troops and cargo over both paved and/or cross country routes. The subject vehicle has a bed  12  resting on a chassis  16  and vertical side-rails or side-walls  14  that extend upwardly from each side of the vehicle bed. Mudflaps  18  and wheels  20  of a conventional nature are shown therein below said bed.  
      Although not shown in this figure, a conforming rail or wall is also transversely provided across the front of the bed to afford troop safety and cargo retention. A rear tail gate may, or may not, also be provided. If it is, it will be an elongated rectangle in form and made of a hard material or an open mesh net with reinforcement. Either form of the tailgate will have conforming receptors thereon that will couple with compatible receptors on the side rails. Examples of intended hard materials are selectable from the group consisting essentially of composite materials, aluminum, and alloys of iron. Mesh nets are usually made of natural and/or synthetic fibers that can be further reinforced or impregnated with compatible rubbers, silicones, plastics, and synthetic polymers to further enhance strength.  
       FIG. 2  is a side view of the cargo vehicle  10  of  FIG. 1  further depicting the extent of overhang between the wheels  20  and the rear of the bed  12 . Absent a rear impact guard, this overhang represents a significant hazard to trailing motor vehicles. In a typical operation cycle, the multifunctional structure  22  predominately remains in a retracted position and functions, under Federal Highway Safety Standards, as a rear impact guard according to  FIG. 3 . Occasionally, this structure will be swept away from the vertical position of  FIG. 3  and into the position of a step ladder as shown in  FIG. 4  to allow troop egress or ingress to the vehicle bed. When a need arises for a cargo platform or ramp, then either version of my structure, as shown in  FIGS. 3 and 4 , can be further extended into the requisite configuration. Finally, the structure  22  is normally returned to a vertical position that downwardly extends to about 1.5 to 2.0 feet from the ground surface  30  once loading/unloading operations have ceased. This particular form of the invention  22  makes an efficient rear impact guard.  
      As shown in  FIG. 3 , the described hazard of  FIG. 2  is surprisingly reduced by the structure of the claimed invention  22 . In  FIG. 3 , the structure  22  is mounted to the chassis  16  at the rear of the vehicle by a joining interconnection of a receiving means  24  on said vehicle and interface assembly means  32  on the top of structure  22 . Suitable materials for compatible receiving means herein include items selectable from a group consisting essentially of a mounting lunette, clevis, pivot, flange, fork, lug, bracket, eyelet, yoke, rivet, weldment, and threaded fastener. The exact selection of which is a matter of availability to the installer, or which will be determined by a cost engineering evaluation during a commercial design and analysis for the production of commercial quantities.  
      Receiving means  24  is multifunctional and can be used for making connections with inward and outward rams  26  and  34 , respectively, of a first actuator means  28  that appears as substantially horizontal in  FIG. 3  for the rear impact guard configuration. Second actuator means  38 , having upper and lower rams  40  and  42 , respectively, are nearly vertically positioned in the rear impact guard configuration with these opposing rams connecting to like receiving means  24  located on the interface assembly means  32  and on a second parallel support means  44 , respectively. The second parallel support means  44  has at least six (three?) pivotal connections, equally spaced apart, that in turn connect to at least three (six?) articulating links  46  that are in mechanical translation with a first parallel support means  48  about a like number (3) of pivotal connections.  
      It will be understood, therefore, that the first and second parallel support means are equally spaced apart at all times due to the rotation or shifting of step means  50  from the vertical to horizontal to angular positions given angular movement of structure  22  from rear impact guard, to step ladder, and then cargo ramp as respectively shown by  FIGS. 3, 4 , and  5 . Since the rails, A and B, respectively, of the first  48  and second  44  parallel support means are also pivotally coupled to the step means  50 , said rails are also dimensionally spaced apart as a continuous parallelogram.  
       FIG. 4  depicts the present invention deployed as a step ladder for mounting and debarking the bed by troops. In this configuration, the first actuator means  28  has further extended inward ram  26  and outward ram  34  to produce an angular sweep away from the vehicle bed to create an angle of about 30° to 60° between said bed  12  and the ground surface  30 . As this occurs, the structure  22  rotates outwardly from the bed of vehicle  10  about a first pivotal connection  36  on interface assembly  32 . This movement causes extension of the first and second parallel support means as a second substantially horizontal actuator moves outward from the rear bed of the vehicle  10 .  
      I wish it understood that I do not desire to be limited to the exact details of construction or method shown herein since obvious modifications will occur to those skilled in the relevant arts without departing from the spirit and scope of the following claims.