Abstract:
A load bearing apparatus is configured to simulate a payload. The load bearing apparatus includes a load member configured to simulate the mass of a payload, a frame having frame members, a plurality of retainers configured to support the load member, and first and second outer guides coupled to the load member. The plurality of retainers includes a first retainer positioned at a first height and configured to support the load member at the first height, and a second retainer positioned at a second height different from the first height and configured to support the load member at the second height. The first and second outer guides are coupled to the load member and are configured to receive therebetween at least one lifting member of a lifting device. By using load members of different weights and positioning them at varying heights, different centers of gravity can be achieved.

Description:
BACKGROUND 
       [0001]    The present invention relates to payload simulation for vehicle testing. 
         [0002]    Payload simulators, or weight simulators, are loaded onto a vehicle or a trailer to add weight and alter the center of gravity of the vehicle to simulate a payload during vehicle testing. Weight simulators include plastic water dummies filled with water to a desired weight, sand boxes filled with sand to a desired weight, concrete blocks, and weighted pallets. These weight simulations lack repeatability and differ from test center to test center. 
       SUMMARY 
       [0003]    In one aspect, the invention provides a load bearing apparatus configured to simulate a payload. The load bearing apparatus includes a load member configured to simulate the mass of a payload, a frame having frame members, and a plurality of retainers supported by the frame and configured to support the load member. The plurality of retainers includes a first retainer positioned at a first height and configured to support the load member at the first height, and a second retainer positioned at a second height different from the first height and configured to support the load member at the second height. 
         [0004]    In another aspect, the invention provides a load bearing apparatus configured to simulate a payload. The load bearing apparatus includes a load member and a frame. The load member is configured to simulate the mass of a payload, and the load member has a predetermined mass. The frame has frame members defining a space configured to at least partially include the load member. The load bearing apparatus also includes means for supporting the load member at a first height and at a second height different from the first height, wherein the load member is configured to be positioned at the first height and configured to be positioned at the second height. 
         [0005]    In yet another aspect, the invention provides a method of simulating a payload. The method includes providing a frame structure having frame members that have a plurality of retainers at a plurality of heights, providing a load member, positioning the load member within the frame structure, and retaining the load member at a first height by coupling the load member to a frame member using at least one of the plurality of retainers. 
         [0006]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a side view of a vehicle and trailer including weight sleds according to one embodiment of the invention. 
           [0008]      FIG. 2A  is a front perspective view of one of the weight sleds of  FIG. 1  having weight slabs. 
           [0009]      FIG. 2B  is a left side view of the weight sled of  FIG. 2A . 
           [0010]      FIG. 3A  is a perspective view of one of the weight slabs of  FIGS. 2A-2B . 
           [0011]      FIG. 3B  is a perspective view of another one of the weight slabs of  FIGS. 2A-2B . 
           [0012]      FIG. 3C  is a perspective view of a weight slab. 
           [0013]      FIG. 3D  is a perspective view of yet another one of the weight slabs of  FIGS. 2A-2B . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
         [0015]      FIG. 1  illustrates a weight sled  10  secured to the bed of a vehicle  14 , and a second weight sled  10   a  secured to a trailer  18  for simulating a vehicle payload and a trailer payload. It is to be understood that the first and second weight sleds  10 ,  10   a  are substantially similar or the same, although they may be arranged to have different weights and centers of gravity, as will be described in greater detail below. The description of the first weight sled  10 , below, can be used to describe the second weight sled  10   a.  The weight sled  10  is secured to a vehicle or trailer, such as a military vehicle or trailer, to simulate the weight and center of gravity of a payload. The weight sled could also be used with other vehicles such as trains, boats, ships or commercial trucks. It is not necessary that both weight sleds  10  and  10   a  be used at the same time. 
         [0016]    With reference to the embodiment shown in  FIGS. 2A-3D , the weight sled  10  has a frame  22  and weight slabs  26   a - 26   d,  or load members, of the same or varying weights. In the illustrated construction, weight slabs of varying weights are shown. As best shown in  FIGS. 1 ,  2 A and  2 B, weights  26   a,    26   b  and  26   c  may be spaced at varying heights to achieve different centers of gravity. For the purpose of description, the frame  22  has a front, a rear, a left side, a right side, a top and a bottom. A base  30  is positioned at the bottom and is preferably structured like a pallet to accommodate a forklift or other lifting device to allow for easy loading and unloading onto a vehicle or trailer. Three guides  34   a - 34   c,  or spacers, of tubular steel or another suitable material are welded, or otherwise fastened, to the bottom of the base  30  to provide a space between the bottom of the base  30  and a support surface  38 . The three guides  34   a - 34   c  include two outer guides  34   a,    34   b  coupled to the base of the frame and preferably one intermediate guide  34   c  positioned between the pair of outer guides  34   a,    34   b  and coupled to the base  30  of the frame  22 . The pair of outer guides  34   a,    34   b  and the intermediate guide  34   c  are substantially parallel. The guides  34   a - 34   c  are dimensioned to provide adequate space to accommodate the tines of a forklift or other lifting vehicle or device. In the illustrated construction, the base  30  is substantially rectangular and has dimensions of approximately forty inches by forty-eight inches, after the weight sled  10  is welded. The base  30  is preferably made of steel; however, in other constructions, other suitable materials may be employed. In other constructions, a structure other than guides  34   a,    34   b  may be used to assist a lifting device in lifting the load member. In the illustrated construction, the weight slabs  26   a - 26   d  are constructed substantially symmetrically and are balanced in weight from front-to-rear and side-to-side. In other constructions, the weight slabs  26   a - 26   d  can be asymmetrically constructed and unbalanced to allow the front-to-rear or side-to-side balance of the weight sled  10  to be varied. 
         [0017]    Four vertical frame members or uprights  42   a - 42   d  are coupled to the base  30 , one upright at each corner of the base  30 . A first upright  42   a  is positioned at the front left corner of the base  30 , a second upright  42   b  is positioned at the rear left corner of the base  30 , a third upright  42   c  is positioned at the front right corner of the base  30 , and a fourth upright  42   d  is positioned at the rear right corner of the base  30 . The uprights  42   a - 42   d  are preferably welded to the base  30 , although other fastening means are also possible. The weight sled  10  has an overall height of approximately sixty-two inches, after welding. The uprights  42   a - 42   d  are preferably made of angle iron; however, other suitable materials may be employed in other constructions. 
         [0018]    The uprights  42   a - 42   d  include retainers for supporting the weight slabs  26   a - 26   d  at a plurality of different heights, as illustrated in  FIGS. 2A-2B . In the illustrated construction, ten apertures  46  are spaced evenly and vertically on each upright  42   a - 42   d.  The weight slabs  26   a - 26   d  include complimentary retaining features  50 , such as end caps in the outer guides  34   a - 34   b  containing complimentary apertures (illustrated in  FIGS. 3A-3D ) or apertures elsewhere in the outer guides  34   a - 34   b  through which fasteners  48 , such as bolts or pins, can be used to couple the weight slabs  26   a - 26   d  to the uprights  42   a - 42   d  of the frame  22 . In other constructions, the retainers may include fixed or removable support brackets, or the like, coupled to the uprights  42   a - 42   d  and providing a support surface on which the weight slabs  26   a - 26   d  can rest. In further constructions, other retainers may be employed to retain the weight slabs  26   a - 26   d  at a plurality of different heights. 
         [0019]    Side cross members  54  are positioned between adjacent uprights  42   a - 42   d  on at least two sides of the frame  22  to provide structural support, rigidity and strength to the frame  22 . In the illustrated construction, the side cross members  54  are formed of strips of steel plate welded in an X-shape from the top of one upright  42   a - 42   d  to the bottom of an adjacent upright  42   a - 42   d.  The side cross members  54  are preferably located on the sides having hooks for tie-downs, which will be described in greater detail below, to compressively absorb the angled loads induced by the tie-downs. In other constructions, the side cross members  54  may be formed of other suitable materials. 
         [0020]    A removable top cross member  58  is bolted to the top of the frame  22  to provide structural support, rigidity and strength to prevent the uprights  42   a - 42   d  from flexing. In the illustrated construction, the top cross member  58  is formed of square tubular steel. The top cross member  58  includes a welded rectangular frame having tubular steel welded in an X-shape between corners of the rectangular frame. The top cross member  58  is bolted to the uprights  42   a - 42   d  such that the top cross member  58  can be removed to allow the weight slabs  26   a - 26   d  to be lowered in and lifted out of the frame  22  by the forklift or other lifting device. In the illustrated construction, the top cross member  58  is welded together to form a single piece for bolting to the uprights  42   a - 42   d;  however, in other constructions, the top cross member  58  may include multiple discrete parts bolted to the uprights  42   a - 42   d  and may be formed of other suitable materials. 
         [0021]    Together, the base  30 , the uprights  42   a - 42   d,  the top cross member  58  and the side cross members  54  define a space in which the weight slabs  26   a - 26   d  are retained. Each weight slab  26   a - 26   d,  or load member, is substantially planar and can be retained in the frame  22  at multiple heights to simulate various centers of gravity, depending on the height chosen. Each weight slab  26   a - 26   d  may have a different weight to further allow for control and variation of the center of gravity—including varying the height of each load member—and overall weight of the weight sled. Multiple weight slabs  26   a - 26   d  having the same weight may also be employed. For example, in the illustrated construction of  FIGS. 2A-2B , three different weight slabs  26   a,    26   b,    26   c  having three different weights are employed. Each weight slab  26   a - 26   d  may be positioned at any of the heights allowed by the retainers  46  to achieve different centers of gravity. The weight slabs  26   a - 26   d  need not be positioned immediately adjacent each other. In other words, the weight slabs  26   a - 26   d  can be retained in the frame  22  while leaving unused retainers  46  in between the weight slabs  26   a - 26   d.  In the illustrated construction, the first weight slab  26   a  is substantially one-thousand pounds ( FIG. 3A ), the second weight slab  26   b  is substantially five-hundred pounds ( FIG. 3B ), and the third weight slab  26   c  is substantially one-hundred pounds ( FIG. 3D ). A fourth weight slab  26   d  weighing substantially two-hundred pounds may also be employed ( FIG. 3C ). In other constructions, weight slabs having other weight values may be employed. In the illustrated construction, the frame  22  is constructed to accommodate up to nine weight slabs  26   a - 26   d  in any combination of weights and heights, and is designed to accommodate this weight at a 5-4-2 G-loading (the equivalent of five gravitational-forces (5 g) vertically, four gravitational-forces longitudinally, and two gravitational-forces laterally). Therefore, the maximum weight of the sled  10  would be nine-thousand pounds plus the weight of the frame  22  itself, equaling approximately ten-thousand pounds in total. To allow for a safety factor, the total weight preferably does not exceed six-thousand pounds. In other constructions, the frame  22  may be constructed to accommodate a different number of weight slabs  26   a - 26   d  having the same or different weight values, depending on the desired load or center of gravity to be simulated. The weight slabs  26   a - 26   d  may also be formed in other shapes and configurations that allow various centers of gravity and overall weights to be simulated. An optional steel box, not shown, may be retained in the frame  22  by way of the retainers  46 . The steel box may contain quantities of sand and/or gravel adjusted for fine-tuning the weight of the sled  10 . Tie-down attachment points and forklift guides, similar to those described below, may be welded or otherwise attached to the steel box. 
         [0022]    Each weight slab  26   a - 26   d  includes a pair of outer guides  62   a,    62   b  coupled to the weight slab  26   a - 26   d  and preferably an intermediate guide  62   c  positioned between the pair of outer guides  62   a,    62   b  and coupled to the weight slab  26   a - 26   d,  such that the weight slab  26   a - 26   d  is transportable by a forklift. The pair of outer guides  62   a,    62   b  and the intermediate guide  62   c  are substantially parallel. The first weight slab  26   a  includes only one set of three guides  62   a - 62   c  because the thickness of the weight slab  26   a  itself substantially equals the thickness of one guide. Weight slabs having a thickness lesser than that of the guides  62   a - 62   c,  such as the second, third and fourth weight slabs  26   b - 26   d,  may include a second set of the three guides  64   a - 64   c,  as illustrated. This ensures that each weight slab  26   a - 26   d  has an overall thickness equal to approximately two guide-thicknesses for ease of storage and transportation. In the illustrate construction, the overall thickness of the weight slabs  26   a - 26   d  including the guides  62   a - 62   c,    64   a - 64   c  is approximately four inches. 
         [0023]    Tie-down attachment points, such as first and second hooks  66   a,    66   b,  respectively, or handles are welded, or otherwise fastened, to the left side of the first and second uprights  42   a,    42   b,  respectively; and third and fourth hooks  66   c,    66   d,  respectively, or handles are welded, or otherwise fastened, to the right side of the third and fourth uprights  42   c,    42   d,  respectively, such that the first and second handles  66   a,    66   b  are opposite the third and fourth handles  66   c,    66   d.  The handles  66   a - 66   d  are structured to provide attachment points for tie-downs  70  (shown in  FIG. 1 ) to secure the frame  22  to the vehicle or trailer to be tested. The vehicle or trailer may already be adapted for receiving the tie-downs, or a frame for the vehicle or trailer may be constructed to be integrated with the vehicle or trailer and to provide the needed tie-down receiving structure for securing the weight sled  10  to the vehicle or trailer. It can be made possible to adjust the location of the weight sled  10  between the front and the rear and left and right of the vehicle or trailer in order to adjust the weight balance from the front to the rear or side to side. The tie-down attachment points, or handles  66   a - 66   d,  could be placed in different locations, including the front or back of the frame, or even the top of the frame if a wider frame is desired. In the illustrated construction, the handles  66   a - 66   d  are made of semi-circular curved steel bar stock; however, in other constructions the handles  66   a - 66   d  may be made of other suitable materials and may have other suitable shapes for providing attachment points for tie-downs. For example, the handles  66   a - 66   d  may be curved, triangular, rectangular, or could be hooks. Furthermore, the handles  66   a - 66   d  may alternatively or additionally be disposed on the front and rear sides of the sled  10 . 
         [0024]    Four gussets  74  are welded, or otherwise fastened, to each upright  42   a - 42   d  at an angle α of approximately 45 degrees relative to each upright  42   a - 42   d.  A first pair of gussets  74  abuts a first end of each handle  66   a - 66   d  and a second pair of gussets  74  abuts a second end of each handle  66   a - 66   d.  The gussets  74  are positioned to strengthen the weld joints where the handles  66   a - 66   d  are welded to the uprights  42   a - 42   d.    
         [0025]    Thus, the invention provides, among other things, a weight sled  10  for simulating the weight and center of gravity of a payload. The weight sled is safe, easy to use, and allows for repeatability of testing. Various features and advantages of the invention are set forth in the following claims.