AU2010355318A1 - Top rail for a body of a haulage vehicle - Google Patents

Abstract

A top rail of a body for a haulage vehicle is constructed to resist structural deterioration resulting from collisions with loading machinery and material falling from the machinery's buckets during the loading process. The top rail of each sidewall of the body comprises a beam capping an open top of a hollow beam running along the length of the sidewall. In cross section, the hollow beam tapers toward the top rail of the sidewall and terminates within an area of the capping beam. Also in cross section, the capping beam has a preferred arcuate shape where the ends of the arc extend beyond the opposing walls whose upper edges form the open top. The capping beam is welded to the outer surface of the opposing sidewalls such that forces from collisions with the top rail transfer to the walls so as to drive the walls together.

Description

WO 2011/159286 PCT/US2010/038719 TOP RAIL FOR A BODY OF A HAULAGE VEHICLE BACKGROUND OF THE INVENTION [0001] Top loaded open top bodies of haulage vehicles such as off-road trucks are typically exposed to significant forces during the process of loading the bodies. Buckets of loading machines release their loads above the bodies and the material falls from the buckets into the bodies with forces proportional to the total mass of each bucket load and the height over the body at which the load is released. [00021 Machines that load the bodies of haulage vehicle are typically either loaders or shovels. Loaders have smaller capacities than shovels. The largest shovels are cable operated with electric winches, although some shovels are hydraulically operated. Shovels often have bottom opening buckets as opposed to loaders whose buckets typically are rotated to pour its contents. Some of the largest shovels can carry 100 - 120 tons or more in their buckets. [00031 Bodies of large trucks made to haul hundreds of tons of material are typically loaded by shovels or the largest of loaders holding tens of tons of material in their buckets. Even at a low height above the bodies, these heavy loads impart large forces on the bodies when released from the buckets, placing the bodies at risk of damage unless they are well designed to withstand the repeated impact of tons of falling material. [00041 However, the most damaging wear on a body occurs when the shovels or loaders inadvertently collide with the top of the sidewalls of the bodies during the loading process. It is not unusual for operators of shovels and loaders to unintentionally collide the buckets with the upper region of the sidewalls. The motion of the bucket in order to load material in the body begins by raising the bucket to a height that clears the sidewalls of the bucket and then swinging the bucket over the floor of the body before releasing the load to fall into the body. In the course of many cycles of loading buckets of material, it often happens that the bucket or an operating arm attached to the bucket inadvertently collides with the top rail of the sidewall of the body. The collision may be a direct hit or a glancing blow. In either case, the forces are great enough to deform the top rail of the sidewall. [0005] Most bodies of the type that carry hundreds of tons comprise a hollow beam construction as a compromise between the strength of solid beams and their weight. In conventional construction for bodies designed to carry hundreds of tons of material, their sidewalls include a transverse beam along the top of the sidewall. The beam is hollow and is WO 2011/159286 PCT/US2010/038719 2 typically formed by inner and outer plates closed at their tops to form the top rail of the sidewall. Transitioning from the double wall of the hollow beam to the top rail takes various forms to provide structural integrity. [0006] In the past, the opening between the tops of the inner and outer plates comprising the transverse beam running along the top of each sidewall has been closed by inserting a beam or another plate into the opening. The beam often has either a round or rhombus shaped cross section. When the beam has a rhombus-shaped cross section, it is oriented to have opposing corners of the rhombus in touch with the tops of the double walls. Beams of round cross section do not require any particular orientation because of their symmetry. The beam is welded into place, which seals the opening to the interior of the sidewall resulting from the double walled construction. [00071 Although this construction of the sidewalls and top rail of a haulage body works well for most applications, it is less than ideal for haulage bodies whose working environments expose the bodies to large forces from collisions with the buckets of the shovels or loaders and their loads. If the force of the collisions with falling material and the buckets of shovels or loaders are great enough, the beam closing the double walls tends to be driven into the hollow between the walls, thereby acting as a wedge to separate the opposing walls and compromising the structural integrity of the body's sidewall. Once the opposing walls separate as the beam forming the top rail of the sidewall is driven into the space between the walls, haulage material thereafter begins to fill in the void between the opposing walls, which aggravates the damage. BRIEF SUMMARY OF THE INVENTION [00081 According to the invention, double-walled sidewalls of a haulage body are capped so that deforming forces resulting from loads hitting the top of the sidewalls tend to drive the inner and outer walls toward one another. Those skilled in the art of designing bodies for haulage vehicles will appreciate that the construction of the sidewalls are a combination of plates and hollow beams. In this regard, reference herein to a double wall of each sidewall refers to the hollow beam construction in that one side of a hollow beam is the inside surface of the sidewall, whereas the other side of the hollow beam is an outside surface of the sidewall. Regardless of whether the sidewall is described as comprising hollow beams or double walls, the resulting construction is characterized by a top rail of the sidewall in which a beam tops and closes an opening between inner and outer plates.

WO 2011/159286 PCT/US2010/038719 3 [00091 By constructing the top rails of the sidewalls in keeping with the invention, they wear in a manner that better resists loss of structural integrity over time than do conventional constructions, allowing the useful life of the sidewalls to more closely track the wear patterns of other parts of the body such as the floor. To assist in resisting deformation of the top rail, the invention contemplates welding ribs along the space between the inner and outer walls. Each rib is welded to the inside surfaces of both the inner and outer walls. A flange of each rib extends upwardly to an area above the top edges of the opposing walls in order to interact with the underside of the cap closing the opening between the opposing walls. Because of the construction of the cap of the top rail described hereinafter, each of the ribs in cooperation with the top rail cap effectively locks the opposing walls into a desired position. The ribs span the interior space between the opposing walls and resists compression when the top rail is hit. The construction of the cap of the top rail, however, resists separation of the opposing walls. Thus, the overall construction of the top rail tends to lock the opposing walls into a fixed relative position that resists change during normal wear and use of the body. [0010] Preferably, an arcuate-shaped beam caps the open top of each double walled sidewall of the haulage body as part of the construction of the body such that the cap overlaps the tops of the opposing walls. By overlapping the top edges of the opposing walls with an arcuate shape, the beam is welded to both the top edges and exterior surfaces of the walls. This construction tends to resist separation of the opposing sidewalls in response to deforming forces such as collisions with buckets of shovels and failing material. [0011] When a force is imparted to the sidewall during its normal use (e.g., collisions with the buckets, its arm or with falling material), the arcuate-shaped beam communicates the energy of the force to the outer edge of the top of the each of the inner and outer walls of the sidewall. The energy is translated to a force that tends to deform the sidewall by distorting the inner and outer walls. However, the ribs resist this deformation and tend to make the top rail more environmentally robust than prior constructions. [00121 Although other shapes may also provide the necessary mechanics described above for the arcuate shape of the beam capping the opposing walls, the preferred construction for the top rail of the sidewalls includes a beam or rail that runs the length of the top rail and has an arcuate cross sectional shape. The arcuate-shaped cross section effectively communicates the force of a collision at the top rail to the inner and outer walls. The arcuate shape may be one or more sections of a circle, an ellipse, a parabola or a hyperbola. Non-arcuate shapes can also be used to cap the sidewalls in keeping with the invention as long as the mechanics WO 2011/159286 PCT/US2010/038719 4 of the interaction of the capping rail and the double walls of the sidewall work to translate the force of the collision from the capping beam to a force that pinches/distorts the inner and outer walls. BRIEF DESCRIPTION OF THE DRAWINGS [00131 Figure 1 is a side view of a haulage vehicle (in phantom line) whose haulage body includes sidewalls constructed in accordance with the invention; [00141 Fig. 2 is a back view of the vehicle and the haulage body of Figure 1, showing one of the two sidewalls isolated within a circle; [0015] Fig. 3 is an enlarged view of the sidewall of Fig. 2, which more clearly illustrates the inner and outer walls of a hollow beam comprising part of the top rail of the sidewall; [0016] Fig. 4 is a perspective view of the haulage body of Figs. 1 and 2, isolated from the vehicle and including selected details of the construction of the inner and outer walls of the hollow beam forming part of the top rail of each sidewall; [00171 Fig. 5 is the perspective view of Fig. 4 with the near sidewall isolated and enlarged to better illustrate the construction of the sidewall; [00181 Fig. 5A is an enlarged view of a circled portion of the sidewall illustrated in Fig. 5, showing the internal construction of the sidewall comprising the inner and outer walls of the hollow beam forming part of a top rail of the sidewall; [0019] Fig. 6 is a cross sectional view of the sidewall of Fig. 5 taken along the line 6-6 in Fig. 5; [0020] Fig. 7 is a cross sectional view of the sidewall of Fig. 5 taken along the line 7-7 in Fig. 5; [00211 Fig. 8 is an exploded view of the sidewall of Fig. 5; [00221 Figs. 9 through 13 illustrate an exemplary sequence for constructing the sidewall of Figs. 5-8 from the various parts illustrated in the exploded view of Fig. 8, where Fig. 9 illustrates (1) an outer bolster plate that mates to an inside body plate to form a hollow beam running along the top of the sidewall whose top forms part of the top rail of the sidewall and (2) spaced support ribs that are welded to the facing surfaces of the outer bolster plate and the inside body plate; Fig. 10 illustrates the partial construction of Fig. 9 added to the inside body plate to complete three sides of the hollow beam; WO 2011/159286 PCT/US2010/038719 5 Fig. 11 illustrates the partial construction of Fig. 10 with the addition of additional outer bolster plates to the inside body plate in order to create additional hollow beams for the sidewall; Fig. 12 illustrates the partial construction of Fig. 11 with the addition of a rail or beam capping the first hollow beam running along the length of the top of the sidewall in order to close the beam and provide a top rail of the sidewall; and Fig. 13 illustrates the partial construction of Fig. 12 with the addition of another outer bolster plate to the inside body plate that extends the body forward to define a side of a canopy of the haulage body. DETAILED DESCRIPTION [0023] The following detailed description primarily describes one of the two sidewalls of the illustrated haulage body. Those skilled in the relevant art will appreciate that the opposing sidewall of the body is a mirror image of the sidewall described in detail hereinafter and that all of the detailed description referencing one sidewall applies equally well to the other sidewall. [00241 Turning to the drawings and referring first to Figure 1, an off-highway truck 11 (shown in phantom) is fitted with a dump body 13 for hauling loads of material. The truck 11 includes a cab 15, front and back axles 17 and 19, respectively, and front and back tires 21 and 23, respectively. The cab 15, axles 17 and 19 and tires 21 and 23 are connected by a frame 25. [00251 Trucks of the type illustrated herein are typically used in large construction or open-pit mining sites that require large amounts of material to be moved. The diameter of the tires 21 and 23 for instance may be approximately 10 feet or more. The trucks are designed to carry hundreds of tons of material in a single load. The largest of these types of trucks can carry close to 400 tons. These trucks are general referred to in the industry as "off-highway haul trucks." [00261 In general, the construction of the truck 11 is conventional and is not described in further detail hereinafter. Examples of the type of truck illustrated in Figure 1 include Komatsu model 960 E-1, Caterpillar model 797-F, Bucyrus model MT6300AC, Liebherr model 282, and Hitachi model EH5000 ACII trucks.

WO 2011/159286 PCT/US2010/038719 6 [0027] The illustrated body 13 is mounted to the frame 25 of the truck 11 at a hinge assembly 27 that includes mating parts of the body and frame. The body 13 is mounted to the frame 25 of the vehicle 11 for rotation about the hinge assembly 27. The body 13 is rotated between raised and lowered positions by a conventional hydraulic system that includes a hydraulic cylinder 29 on each side of the truck 11 that connects to the frame 25 and the body 13. Extension of the hydraulic cylinders 29 causes the body 13 to rotate about the hinge 27 from the lowered position illustrated in Figure 1 to a raised position that dumps the load carried by the body. [0028] As best seen in Fig. 4, the general configuration of the body 13 includes a floor 31, two opposing sidewalls 33, a front slope 35 and a canopy 37 extending forward from the front slope. In the illustrated embodiment, the body 13 is shown to have a generally "ducktailed" rear floor construction, which provides for a angled floor 31 that serves to hold the material of a load in the body without requiring a tailgate. However, a tailgate (not shown) can be added to the body 13 to increase capacity of the body for low density loads. Those skilled in the art will appreciate that the invention described herein is not limited in its application to "duckbilled" type truck bodies. To the contrary, the invention can be incorporated into any type of truck body, including for example truck bodies with level floors and tailgates. Also, the invention described herein applies equally well to stationary bodies as it does to the illustrated dump body 13. For example, the invention is applicable to rear eject bodies such as that illustrated in US Patent No. 7,326,023, which is hereby incorporated by reference. [00291 The invention finds its greatest utility in large, off-highway trucks and in environments in which the body 13 is loaded by large shovels or loaders whose buckets can cause damage to the body if the bucket or the arms supporting the bucket collide with the sidewalls. When collisions occur, they typically happen at the top rail of the sidewall. Also, material falling from the bucket may hit the top rail with a relatively large force. In open-pit mining operations, the material being loaded is for example large rocks or mined ore that may have a granulation such that a single piece weighs in excess of 20 tons. Exposure of the top rails 39 of the body 13 to this difficult environment can deform the top rails over repeated loading of the body. [00301 In accordance with the invention, however, the construction of the top rails 39 are such that their deformation caused by collisions with the loading machinery and the material being loaded tends to maintain the integrity of the sidewalls so that their useful life WO 2011/159286 PCT/US2010/038719 7 approximates the useful life of the other parts of the body. Construction of the top rail resists splitting the opposing inner and outer walls forming the top rail, which exposes the interior of the hollow beam formed by the inner and outer walls to a loss of structural integrity and filling with material, which contributes to further deterioration of the sidewall. [00311 Figs. 2 and 3 illustrate the body 13 as seen in its lowered position, resting on the frame 25 of the truck 11. From this view of the body 13, the underside of the floor 31 is best seen. The construction of the floor 31 includes cross beams 41 that provide support for the weight of the load. The beams are typically of a hollow beam construction. Details of the floor's construction are not provided herein. They are conventional and well known in the art. [00321 A rear view of the sidewalls 33 in Figs. 2 and 3 shows each sidewall including a bevel 43 of an outer bolster plate 45 mated to an inside body plate 47 to form a hollow beam that runs along the top length of the sidewall. For each of the sidewalls 33, the bevel 43 is an angled section at a terminal portion of the outer bolster plate 45 that cooperates with a terminal portion 49 of the inside body plate 47 and an arcuate-shaped plate or beam 51 to form the top rail 39 of the sidewall. The arcuate beam 51 receives within its interior space, as most easily seen in Fig. 3, the terminal portion of the inside body plate 47 and the beveled, terminal portion of the outer bolster plate 45. By mating the arcuate beam 51 to the terminal portions of the plates 45 and 47 in this manner to form the top rail 39, collisions with buckets of loading machines and falling heavy pieces of material tend to cause the outside bolster plate to bend at an elbow 53 of the bevel 43. The bending of the outer bolster plate 45 in response to deforming forces on the sidewall 33 causes the area of the bevel 43 at the terminal portion of the outer bolster plate to distort inwardly or outwardly from the terminal portion 49 of the inside body plate 47. [0033] Because of the arcuate, cross-sectional shape of the beam 51 extends beyond the top edges of the plates 45 and 47, the beam tends to communicate the force of collisions with the top rail 39 along the beam and to outer, upper edges of the outer bolster plate 45 and the inside body plate 47. The arcuate beam 51 caps the terminal portions of the plates 45 and 47 in that the terminal portions of the plates fit inside the concave area defined by the arcuate shape of the beam. In the illustrated embodiment, the arcuate, cross-sectional shape of the beam 51 is a section of a circle. The radius of the circle is selected so that the ends of the arcuate section extend over the top edges of the terminal portions of the plates 45 and 47. By providing this relationship between the arcuate beam 51 and the plates 45 and 47, the beam WO 2011/159286 PCT/US2010/038719 8 mates to the upper edges of the plates 45 and 47 at the outer surfaces. By its shape, the arcuate beam 51 communicates much of the force of a collision to the plates 45 and 47. The force transfers at the outer edges of the terminal portions of the plates 45 and 47 because that is the area where the arcuate beam 51 mates and welds to the plates 45 and 47. [0034] Although a circular cross section for the arcuate shape of the beam 51 is preferred, other generally arcuate shapes are also possible. For example, the arcuate shape may be part of an ellipse, a parabola or a hyperbola. The beam 51 could have shapes other than sections of arcs, as long as the shape of the beam is effective in communicating the force of collisions to the outer edges of plates 45 and 47. [0035] The forces transferred to the plates 45 and 47 from the arcuate beam 51 tend to pinch the plates 45 and 47 together. If the forces are great enough to bend the plates 45 and 47, the initial bending most often occurs at the elbow 53 of the bevel 43. If the bending is great enough, the metal of the outer bolster plate 45 permanently deforms, resulting in the bevel 43 at the terminal portion of the outer bolster plate 45 moving inwardly or outwardly from the terminal portion 49 of the inside body plate 47. If the arcuate beam 51 is impacted with a deforming downward force, the deformation tends to strengthen the opposing walls 45 and 47 [0036] As best seen in Figs. 2 through 5, an end 54 of the beam formed by the plates 45 and 47 is a flat plate that is welded to the plates in order to close the end opening between them. The end 54 can include a section of the arcuate beam 51 from the top rail 39 in keeping with the invention. The end 54, however, is the part of the sidewall 33 that transitions the top rail 39 of the sidewall to the open rear of the body 13 or to an area that mates with a tailgate. As such, this area of the sidewall 33 is not exposed to collisions with the loading machinery or material falling from buckets to the same degree as the top rail. Also, the end 54 is sloped and collisions with it tend to be more glancing blows. Nevertheless, if desired the end 54 can incorporate a construction similar to the top rail construction as described herein. [0037] Referring now to Fig. 4, a perspective view of the body 13 includes a plurality of ribs 55 that reinforce the space between the inside body plate 47 and the outer bolster plate 45. The ribs 55 are also illustrated in Fig. 5 and the isolated and enlarged view in Fig. 5A. The ribs 55 are spaced along the gap between the terminal portions of the inside body plate 47 and the outer bolster plate 45. The ribs 55 tend to help reduce deformation of the top rail WO 2011/159286 PCT/US2010/038719 9 39 comprising the arcuate beam 51 and the terminal areas of the outer bolster plate 45 and the inside body plate 47. [00381 As best appreciated from the cross sectional views of one of the sidewalls 33 illustrated in Figs. 6 and 7, which are taken along lines 6-6 and 7-7, respectively, in Fig. 5, the ribs 55 are welded to inside surfaces of the plates 45 and 47. Collisions with the top rail 39 tend to distort plates 45 and 47 and place the ribs 55 in compression. The ribs 55 resist the compression. However, the capping of the upper edges of the terminal portions of the plates 45 and 47 by the arcuate beam 51 resists outward movement of the plates 45 and 47, which results in a construction of the top rail 39 that effectively locks the plates 45 and 47 in relative position. This effective locking of the relative positions of the plates 45 and 47 further strengthens the top rail and helps it resist damage from collisions with buckets and falling material. [00391 Both cross sections of Figs. 6 and 7 include views of lower outer bolster side plates that mate with the inside body plate 47 to provide hollow beams contributing to the construction of the sidewall 33. In the cross section illustrated in Fig. 6, a first lower, outer bolster plate 57 is attached to a forward area of the inside body plate 47. A second lower, outer bolster plate 59 is attached to a rearward area of the inside body plate 47, which can be seen in the cross sectional view in Fig. 7. Both views in Figs. 6 and 7 illustrate a stiffener 61 not illustrated in the other drawing figures, which serves to reinforce the space between the outer bolster plate 45 and the inside body plate 47 that forms the beam running the length of the sidewall 33 and whose top portion defines the top rail of the sidewall. Preferably, the stiffener 61 is a continuous L-shaped beam that runs the length of the space between the outer bolster plate 45 and the inside body plate 47. It is positioned below the ribs 55 and contributes to the overall strength of the hollow beam. During construction, the stiffener 61 is welded to the outer bolster plate 45. The plate 45 is then mated to the inside body plate as explained in connection with Fig. 10. Holes in the inside body plate allow the stiffener to be "plug" welded to the inside body plate. "Plug" welding is a well known welding technique and is not described in further detail herein. [00401 Referring now to Fig. 8, an exploded view of the sidewall 33 illustrates each of its major components. The inside body plate 47 is the main component and substantially defines the overall shape of the sidewall 33. The bolster plates 45, 57 and 59 are welded to the inside body plate 47 to form a hollow beam construction for the sidewall. Additional outer bolster plates 63 and 65 are welded to the inside body plate 47 to form hollow beams in the front WO 2011/159286 PCT/US2010/038719 10 area of the sidewall 33 that transitions the sidewall to a side of the canopy 37 that extends over the cab 15 of the vehicle 11. Each of the ribs 55 is welded to the inside of the hollow beam formed by the inside body plate 47 and the outer bolster plate 45. Referring to Figs. 6 and 7, each rib 55 includes a flange 55a extending upwardly and above the upper edges of the terminal portions of the plates 45 and 47. The flanges 55a end in an arcuate shape that complements the arcuate shape of the beam 51 and preferably contact the underside of the beam 51 when the plate is welded to the plates 45 and 47 to complete the construction of the top rail 39. The steel comprising the several parts of the sidewall 33 is a high strength/low carbon steel typically used for the type of bodies mated to off-highway haul trucks. [0041] The sidewall 33 can be constructed in a number of different ways. Figs. 9 through 13 illustrate a sequence of construction in keeping with the one presently used. First, the ribs 55 are welded to the outer bolster plate 45 as illustrated in Fig. 9. The number and separation of the ribs 55 along the length of the plate 45 is proportional to the strength desired for the sidewall. In the illustrated embodiment, the outer bolster plate 45 is approximately 25 feet long and the ribs are separated by about 1 /2 feet. [00421 Once the ribs 55 are welded to the outer bolster beam 45, the beam is welded to the inside body plate 47 as illustrated in Fig. 10. The opening at the top rail 39 of the sidewall under construction allows the ribs 55 to be welded to the inside body plate 47. [0043] After the outer bolster plate 45 has been welded in place, the bolster plates 57, 59 and 63 are next welded into place as illustrated in Fig. 11. There is no particular sequence for the welding of these three plates. [0044] In Fig. 12, the arcuate beam 51 caps the opening between the inside body plate 47 and the outer bolster plate 45 and then welded in place to complete the top rail 39 of the sidewall 33. Before adding the beam 51, the plate 54 is added to close the back of the hollow beam formed by the plates 45 and 47. [0045] The last bolster plate 65 is welded to the inside body plate 47 in Fig. 13. The plate 65 extends over the top of the outer bolster plate 45 and the two are spot welded or "plug" welded together at small holes (not shown) in the plate 65. [0046] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

WO 2011/159286 PCT/US2010/038719 11 [0047] The use of the terms "a" and "an" and "the" and similar references in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. In this regard, one of the sidewalls 33 has been described in detail, but the description applies equally well to the other, opposing sidewall. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. The method described herein can be performed in any suitable order unless otherwise indicated or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and is not aimed at posing a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. [0048] A preferred embodiment of this invention is described herein, including the best mode known to the inventor for carrying out the invention. Variations of this preferred embodiment may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate and the inventor intends for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims (16)

1. A body for mounting to a haulage vehicle comprising: a floor for supporting a load; opposing sidewalls extending upwardly from each lateral side of the floor; each sidewall having an inside body plate and at least one outside bolster plate forming inner and outer walls, respectively, of the sidewall; the inner and outer walls of each sidewall extending upwardly to upper edges that mate to a top rail of the sidewall; a plurality of ribs each spanning the inner and outer walls of each sidewall at an area proximate the top rail, where the ribs are spaced along the length of the sidewall to provide structural integrity to the sidewall; and a beam spanning and capping the upper edges of the inner and outer walls of each sidewall to form a top rail of the sidewall, where the beam overlaps the upper edges of the inner and outer walls such that separation of the upper edges resulting from collisions is resisted by the overlapping top rail and relative movement of the opposing walls resulting from collisions is resisted by the plurality of ribs.

2. The body of claim 1 wherein the body is a dump body mounted to a frame of the haulage vehicle to rotate about an axis in order to dump the load.

3. The body of claim 1 wherein each of the ribs is in contact with an underside of the beam.

4. The body of claim 3 wherein each of the ribs contacts the underside of the beam at a flange extending above the upper edges of the inner and outer walls.

5. The body of claim 1 including a section that forms a canopy over a cab of the haulage vehicle.

6. The body of claim 1 wherein the outside bolster plate fits to a top portion of the inside body plate to form a hollow beam running the length of the sidewall. WO 2011/159286 PCT/US2010/038719 13

7. The body of claim 1 wherein the beam has a generally arcuate cross section whose ends extend the beam over the upper edges of the inner and outer walls.

8. The body of claim 7 wherein the arcuate cross section is a section of a circle whose radius is such that the ends of the section form a concaved area that receives the upper edges of the inner and outer walls.

9. The body of claim 1 wherein the inner and outer walls of each sidewall cooperate in cross section to taper proximate where the sidewall transitions to the top rail.

10. A method of making a body for a haulage vehicle comprising; forming plates into a hollow beam running along a length of a sidewall of the body and with opposing walls and an open top contributing to a top rail of the sidewall; and capping the open top of the beam to complete the formation of the top rail and allowing edges of the opposing walls defining the open top to be received into a convex shaped area of the cap facing the open top such that the cap is welded to outside surfaces of the edges defining the open top.

11. The method of claim 10 in which a cross section of the sidewall at terminal portions of the opposing walls ending in the open top is generally tapered to where the opposing walls form the top rail.

12. The method of claim 10 including adding supporting ribs between the opposing walls to resist relative movement of the walls.

13. The method of claim 10 including forming a beam that defines a side of a canopy of the body for protecting a cab of the haulage body when the body is placed on the vehicle, where the beam for the canopy mates to the beam contributing to the top rail.

14. The method of claim 12 including extending the ribs into the convex-shaped area so that the ribs are in close proximity to a surface of the cap of the top rail. WO 2011/159286 PCT/US2010/038719 14

15. The method of claim 10 wherein the open top of the opposing walls is capped by a beam having an arcuate cross section.

16. The method of claim 15 in which the arcuate cross section is a section of an arc whose endpoints extend beyond the edges of the opposing walls defining the open top.