P/00/011 28/5/91 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Roadwest Transport Equipment & Sales Pty Ltd Actual Inventors: Peter Frank Lombardi Ravi Subramaniam Address for service is: GOLJA HAINES & FRIEND 35 Wickham Street East Perth, WA 6004 Attorney Code: Invention Title: Tipper Body Construction Divisional Application Details: Original application no 2005220210 The following statement is a full description of this invention, including the best method of performing it known to me: 1 "Tipper Body Construction" Field of the Invention 5 This invention relates to bulk solids material handling, and in particular to a vehicle for transporting bulk solids. This invention has particular application in bulk solids transporting vehicles that have a body that contains bulk solids, and is emptied by tipping the body about a pivot axis. Background Bulk solids transporting vehicles have long been used for transport of bulk solids 10 such as rock and ore from mine sites. Typically, these vehicles which often have rear or side tipping bodies for discharging of their loads, are loaded using overhead hoppers, forklifts, front end loaders, or excavator buckets, with front end loaders being most common. In applications on mine-sites, the vehicles can be quite large, having a payload 80 tonnes or more. Where the vehicle is to be 15 used on the roads, the maximum payload is likely to be between 35 and 40 tonnes. In loading these vehicles, the loader can deliver as a batch, between 3% and 30% of the payload of the vehicle. Often, the loader will drop ore including large 20 rocks into the vehicle. With the weight of a batch being loaded possibly lying between one and ten tonnes, the initial load dropped into an empty vehicle body can deliver energy from the impact on the structure of the vehicle body and chassis. Hitherto, to deal with this problem, the vehicle body has been constructed with longitudinal structural members or a structural frame comprising 25 longitudinal members and cross-members (a ladder configuration) providing support under the base of the body to give some strength against energy imparted from impacts from rocks as the vehicle is loaded. Such an arrangement of longitudinal structural members or a structural frame 30 comprising longitudinal members and cross-members is provided in addition to 2 5 the chassis of the vehicle. While some deformation over time in the longitudinal structural members or structural frame can be tolerated as normal wear and tear, any significant structural deformation in the chassis will render the vehicle unserviceable. 10 The loading of the vehicle can also impact on the side walls of the body. In order to deal with these impact forces, manufacturers fabricate vehicle bodies with coaming which extends along edges and provides reinforcement against impacts, to minimize deformation of the side walls of the body. The word "coaming" has nautical origins, meaning a raised border around a hatchway or 15 roof opening, etc., to keep out water. While the purpose of coaming in bulk load carrying vehicle bodies is not the same, the physical structure, being like a raised frame extending along edges of the vehicle body, bears a likeness to nautical coaming. 20 Hitherto, vehicle body manufacturers have fabricated coaming using rectangular hollow section (RHS) mild steel which forms a border around the edges of sides of the vehicle body. This is often further reinforced by use of vertically extending RHS along the sides of the vehicle body, extending downward from the upper side coaming, in a ladder-like construction. 25 The preceding discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in 30 Australia or elsewhere as at the priority date of the application. It is an object of this invention to provide a vehicle for transporting bulk solids which overcomes disadvantages inherent in the aforementioned configuration, or at least provides an alternative to the aforementioned arrangement. 35 Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood 3 5 to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Disclosure of the Invention The inventors have developed a new and alternative structural configuration for a vehicle having a body for transporting bulk solids, where the body of the vehicle is supported with the central load receiving portion of its base located in spaced 10 configuration above the chassis of the vehicle, and at least the base of the body is formed of resiliently deformable material which provides structural support for the load. The base of the body is able to yield under impact from material as it is loaded. In use, the base of the body need only withstand the impact of the first material loaded into the body without transmitting the energy of the impact 15 directly to the underlying vehicle chassis, as it is the first material loaded that dissipates energy directly into the base, and over a small area of the base. As subsequent material is loaded on top of earlier loaded material, the earlier loaded material spreads the energy over a larger area of the base. Ultimately, as loading proceeds, the base of the body may deflect to the extent that it rests on 20 the upper surface of the vehicle chassis, but when this state of affairs is reached, energy from impacting material being loaded will dissipate through the material already loaded and any energy impacting on the base of the body and the underlying chassis of the vehicle will be well dispersed, so as not to cause damage to the chassis. 25 In conjunction with this, the inventors have developed a new arrangement of coaming and side wall construction for use in the sides of vehicles for transporting bulk solids. 30 Thus, in accordance with one aspect of the invention there is provided a vehicle for transporting bulk solids, the vehicle having a body provided to contain bulk solids said body having a base and sides, said vehicle having a chassis having a pair of longitudinal rails, said body being pivotally connected to said chassis for tipping about hinged mounting points located along a lower edge of said body, 4 5 and said vehicle including hydraulic rams utilized for tipping said body about said hinged mounting points; said body resting above said chassis on elevating mounts located under the body around the periphery of said body, between said body and said longitudinal rails, at least said base of said body being formed substantially of single sheet thickness of resiliently deformable sheet material 10 which provides structural support for the load. The mounts are elevating in the sense that they locate the body, when empty, spaced above the chassis by an air gap, and not in direct contact with the chassis. The air gap provides space for the body to yield under the impact energy of material, rocks etc being loaded, to minimise contact of the body with the chassis, and minimise energy directly 15 impacting the chassis. In use, when loading of the body commences, the bulk material is always emptied into the middle of the body, away from the peripheral positions, so the probability of the first part of a load impacting in close proximity to the elevating mounts and dissipating energy into the chassis through the elevating mounts, is remote. As loading proceeds, the body may come into 20 contact with the chassis though the weight of the load deforming the body, but the impact from material being loaded will be diffused through material already loaded, and not concentrated on a particular point of the chassis which could give rise to damage to the chassis. 25 Preferably said hinged mounting points are spaced away from said lower edge of said body. Preferably said hydraulic rams utilised for tipping said body about said hinged mounting points for discharging load from said body, are arranged in use to be 30 maintained under pressure in a loaded condition. Preferably said elevating mounts comprise four raised pads arranged spatially in rectangular configuration located on said pair of longitudinal rails of said chassis under said base, and proximal to forward and rearward sides of said body. 35 Preferably said raised pads are formed of a substantially non-resilient material such as mild steel. 5 5 Preferably said elevating mounts provide a void between said base and said chassis, said void being located along the longitudinal extent of said chassis, between said raised pads, where with the body unloaded, the base does not contact the chassis. 10 Preferably the chassis is formed of said pair of longitudinal rails having spaced cross-members, and said raised pads each comprise a plate member secured to an upper portion of the longitudinal rails. Preferably said elevating mounts also include at least two further plate members 15 secured to the underside of the base of said body, to rest on each said plate member. There may be only two further plate members which extend laterally across the underside of the base of said body, or four discrete further plate members located so as to be in alignment with the plate members attached to the chassis, or a combination of the two arrangements (ie one further lateral 20 plate member and two further aligned plate members). Alternatively the chassis is formed of a pair of longitudinal rails having spaced cross-members, and said elevating mounts comprise at least two plate members secured to the underside of the base of said body to rest on the longitudinal rails. 25 In use, in the unloaded condition, the body will not contact the chassis through the raised pads/plate members, however as the body is loaded, the body may come into contact with the chassis through the raised pads/plate members. 30 Preferably said hinged mounting points are located along a longitudinal side of the vehicle to configure said vehicle as a side tipping vehicle. The vehicle may be a truck or a trailer for a prime mover or in a road train. Preferably said sides of said body are also formed of resiliently deformable sheet 35 material. Reinforcing can be provided through external flanges at the end, and coaming along longitudinal edges to prevent outward flexing of the walls. 6 5 Preferably the fixed walls and base are fully welded, to form a rigid structure. Further reinforcing can be provided by welding a web at the intersection between at least fore and aft walls and the base. In accordance with a second aspect of the invention there is provided a 10 longitudinal side wall in a body for a vehicle for transporting bulk solids, said side wall between its forward and rearward extents consisting of single sheet thickness resiliently deformable sheet material having longitudinally extending coaming formed of single sheet thickness resiliently deformable sheet material, said coaming extending along an upper edge of said side wall to reinforce said 15 side wall against outward flexing; said coaming extending longitudinally from the top of said side wall, down to a weld line extending longitudinally below the top of said side wall, spaced from the top of said side wall, said weld line securing a lowermost edge of said coaming sheet material to said side wall sheet material, said coaming having a portion of said sheet material extending above and along 20 said weld line substantially lying against said side wall sheet material; said longitudinal side wall between its forward and rearward extents, consisting solely of two sheets of said single sheet thickness resiliently deformable sheet material between the top of said side wall and said weld line, and consisting solely of one sheet of said single sheet thickness resiliently deformable sheet material below 25 said weld line down to a base of said body, said resiliently deformable sheet material comprising sheet material having at least 370 Brinell hardness and a yield strength of at least 1000Mpa. Also in accordance with a second aspect of the invention there is provided a 30 longitudinal side wall forming a side opening door in a body for a vehicle for transporting bulk solids, said side wall between its forward and rearward extents consisting of single sheet thickness resiliently deformable sheet material having longitudinally extending coaming formed of single sheet thickness resiliently deformable sheet material, said coaming extending along an upper edge of said 35 side wall to reinforce said side wall against outward flexing; said coaming extending longitudinally from the top of said side wall, down to a weld line extending longitudinally below the top of said side wall, spaced from the top of 7 5 said side wall, said weld line securing a lowermost edge of said coaming sheet material to said side wall sheet material, said coaming having a portion of said sheet material extending above and along said weld line substantially lying against said side wall sheet material; said longitudinal side wall between its forward and rearward extents, consisting solely of two sheets of said single sheet 10 thickness resiliently deformable sheet material between the top of said side wall and said weld line, and consisting solely of one sheet of said single sheet thickness resiliently deformable sheet material below said weld line down proximal to a hinge located at a base of said body, said resiliently deformable sheet material comprising sheet material having at least 370 Brinell hardness 15 and a yield strength of at least 1 00OMpa. Preferably said side wall sheet material and said coaming sheet material have substantially identical hardness and yield strength properties. 20 Preferably said side wall sheet material has a slight outward curve so as to be convex when viewed from the inside of the body. Also in accordance with the second aspect of the invention there is provided a vehicle for transporting bulk solids, the vehicle having a body provided to contain 25 bulk solids, said body having a base and sides, and a longitudinal side wall forming a side opening door as described above, the side opening door being mounted on a hinge located along the lower extent of said base. Also in accordance with the second aspect of the invention there is provided a 30 vehicle for transporting bulk solids, the vehicle having a body provided to contain bulk solids, the body having a base and sides, including a longitudinal side wall as described above. Preferably the body has a door as described above. Preferably the base is formed of resiliently deformable sheet material. 35 Preferably the base is formed of resiliently deformable sheet material and the side wall is formed with a curvature to meet the plane of the base. 8 5 Preferably the side wall meets the plane of the base in overlapping manner, and is secured thereto by fillet welds extending longitudinally on the inside of the body and on the outside of the body. 10 Alternatively in a preferred form, the base and the side wall are of unitary construction formed from a single sheet of said resiliently deformable sheet material, and are formed with longitudinally extending creases/bends to provide improved rigidity. 15 Preferably said resiliently deformable sheet material comprises sheet having about 400 Brinell hardness. The sheet material may be quench tempered plate, wear grade steel, high impact steel or high tensile steel. In practice sheet having Brinell hardness of 450, 500, 550, or 600 may be employed. A yield strength of up to 1800 Mpa, is preferred, with 1200 to 1500 Mpa being most suitable. 20 Preferably the base is formed of a single sheet of said resiliently deformable sheet material. Preferably the base is substantially flat. 25 Preferably the base is of unreinforced single sheet construction to allow the base to flex. Brief Description of the Drawings Three preferred embodiments of the invention will now be described in the following description of a trailer for transporting bulk solids, made with reference 30 to the drawings in which: Figure 1 is a third angle orthographic projection of the trailer according to the first embodiment of the invention; Figure 2 is a third angle orthographic projection of the trailer of figure 1 showing the discharge door in the open position; 9 5 Figure 3 is a third angle orthographic projection of the trailer of figure 1 showing the discharge door in the open position and the body in the tipping position to discharge the load; Figure 4 is an orthogonal projection from the right rear of the trailer of figure 1; 10 Figure 5 is an orthogonal projection from the right rear of the trailer of figure 1 showing the discharge door in the open position; Figure 6 is an orthogonal projection from the right rear of the trailer of figure 1 showing the discharge door in the open position and the body in the tipping position to discharge the load; 15 Figure 7 is an orthogonal projection from the left front of the trailer of figure 1 showing the discharge door in the open position and the body in the tipping position to discharge the load; Figure 8 is a longitudinal section through A-A in figure 1, of the chassis and body of the trailer of the first embodiment; 20 Figure 9 is also a longitudinal section through A-A in figure 1, of the chassis and body of the trailer of the first embodiment showing deflection of the base of the body under load; Figure 10 is a lateral section through B-B in figure 1, of the chassis and body of the trailer of the first embodiment; 25 Figure 11 is an orthogonal projection from the right rear of the trailer of the second embodiment showing the discharge door in the open position; Figure 12 is an orthogonal projection from the left front of the trailer of the second embodiment showing the discharge door in the open position and the body in the tipping position to discharge the load; 30 Figure 13 is a lateral section through the trailer of the second embodiment, equivalent to the view of the first embodiment in figure 10 Figure 14 is an orthogonal projection from the left front of the trailer of the third embodiment showing the discharge door in the open position and the body in the tipping position to discharge the load; and 35 Figure 15 is a lateral section through the trailer of the third embodiment, equivalent to the view of the first embodiment in figure 10. 10 Best Mode(s) for Carrying Out the Invention 5 All of the embodiments are a trailer 11 for a road train, suitable for both on-road and off-road use. The first embodiment of the trailer is illustrated in figures 1 to 10. Referring to figure 1 in particular, the trailer 11 has an open-topped body 13 supported on a chassis 15. The chassis 15 has a triple axle and wheel assembly 17, 19, 21 at the rear 23 thereof, and has a mount 25 at the front 27 for fitting a 10 king pin for receiving in a turn-table of a prime-mover or dolly. A skip plate 28 is provided underneath the chassis 15 at the front 27 of the trailer. The skip plate 28 is lubricated and contacts the top of the turn-table of the prime-mover or dolly. The chassis 15 has a pair of landing legs 29 which are manually jacked down to support the trailer when not connected to the turn-table. 15 Referring also to figure 7, the chassis 15 has two longitudinal rails 31 and 33, each being formed of a web 35 and an upper and lower flange 37. The web is 5mm thick mild steel, and flange is 130mm x 16mm flat bar, fully fillet welded together (both sides) for structural strength. Referring to figure 7 and 8, the 20 longitudinal rails 31 and 33 are joined (fully fillet welded) by six cross-members 39, 41, 43, 45, 47, and 49 also comprising a web 51 and an upper and lower flange 53, of the same materials as used in the chassis rails 31 and 33. Each of the six cross-members 39, 41, 43, 45, 47, and 49 has an aperture 55 in the web 51 for running services (electrical cabling, hydraulic and compressed air lines). 25 Referring to figure 1, a rearmost cross-member 57 is also provided, fillet welded to the longitudinal rails 31 and 33, on which is supported a Ringfeder T M coupling 59 for connecting a bogey or further trailer to be towed, to form a road train. Referring back to figure 7, the chassis 15 includes hinged mounting points 30 formed by outriggers 61 with hinges, supporting the body 13 from the chassis, for rotating the body to tip the load from the body. The out-riggers 61 are fillet welded to the chassis rail 33. The out-riggers each have three 5mm thick webs 63 and flange 65 formed from 150mm x 16mm, and are formed from mild steel. 11 5 The open topped body 13 has a base 67 bounded by sides to form an enclosure 69 for containing bulk solids for transport. The sides comprise a forward wall 71 and a rearward wall 73, fillet welded to the base 67, and to a side wall 75. Structural rigidity is provided in the upper extents of the forward wall 71 and the rearward wall 73 by obliquely outwardly extending portions 77 formed with 10 flanges 78 formed integrally therewith, and right angle section 79 and web 81 secured also by fillet welding at the fold between the portions 77 and respective wall 71, 73. Webs 83 are welded to the base 67 and the forward wall 71 and to the base 67 and the rearward wall 73 to provide added strength. 15 Referring to figure 10, the side wall 75 is shown relative to the edge 85 of the forward wall 71 (and rearward wall 73). The side wall 75 comprises a curved structural portion 87, and reinforcement against flexing by coaming 89, the coaming 89 being joined to the curved structural portion 87 by a longitudinally extending butt weld 91 and fillet weld 92. The curved structural portion 87 is fillet 20 welded to and extends below the base 67, and both are also welded to a longitudinally extending body runner 93, the body runner 93 being provided for structural rigidity and strength. The curved structural portion 87, coating 89, and body runner 93 are welded to the forward wall 71 and the rearward wall 73. The curved structural portion 87 is secured at the top thereof to the forward wall 25 71 and the rearward wall 73 by bolted joints 94, at the top of the wails, to provide additional strength, to prevent shearing at the welds. The enclosure 69 is completed by an outwardly opening door 95 mounted on a hinge 97 located along the lower extent of the base 67. Movement of the door 30 95 between the closed position as shown in figures 1, 4, and 10, and the open position as shown in figures 2, 3, 5, 6, and 7 is controlled by two double acting hydraulic rams 99, one located at each end (forward and rearward) of the body 13. 35 The outwardly opening door 95 has a slight outward curve, being convex when viewed from inside the body, and its location when closed is shown relative to the edge 101 of the forward wall 71 (and rearward wall 73). Reinforcement against 12 5 flexing of the door 95 is provided by coaming 103, the coaming 103 being joined to the door 95 by a longitudinally extending butt weld 105 and fillet weld 107. The curvature in the outwardly opening door 95 also assists in reinforcing the door 95 against flexing. 10 The coaming 89 and 103 extends longitudinally along the upper extents of the side wall 75 and outwardly opening door 95, respectively, as can be seen in figures 4 and 5 in particular. Referring to figure 10, the coaming 89 and 103 each extend up to a peak 108 shaped like a shallow inverted vee, which is designed to allow any material being loaded to spill off to either side, and not be 15 retained where it may fall off and be a hazard to other road users. The coaming 89 extends downward from the peak 108, along a portion 108A which is generally spaced from the side wall 75. Similarly the coaming 103 also extends downward from the peak 108, along a portion 108A' which is generally 20 spaced from the sheet material forming the door 95. The coaming 89 and 103 each include an obtuse angled longitudinal fold 108B and 108B' respectively at the bottom of portions 108A, 108A', marking a boundary between the portions 108A 108A', and sheet portions 108C 1080'. The sheet portions 108C and 108C' each extend convergently downward at an acute angle to the sheet 25 material forming the side wall 75 and to the sheet material forming the door 95, respectively. Where the sheet portions 108C and 108C' meet the sheet material forming the side wall 75 and door 95 respectively, there is an obtuse angled longitudinal fold 108D and 108D' in the coaming 89 and 103 respectively, Below the obtuse angled longitudinal fold 108D and 108D', the coaming 89 and 103 30 extends further downward in a further sheet portion 108E and 108E'. The further sheet portions 108E and 108E' substantially lie against said sheet material sheet material forming the side wall 75 and door 95 respectively, and are fillet welded 92 and 107 to this sheet material along a lower edge of the further sheet portion 108E and 108E'. This arrangement of convergent downward extending of the 35 coaming to a fold whereafter the coaming continues along against the sheet material of the side wall 75 and of the door 95, to the position where it is welded 13 5 to the sheet material, is believed to direct any impact forces on the peak 108 in a manner that minimizes shear stresses on the welds 92 and 107. The body 13 is supported on three hinges 109 located in the outriggers 61, the hinges 109 allowing for pivoting of the body in side tipping manner to discharge 10 the load, as shown in figures 3, 6, and 7. Tipping of the body 13 is controlled by two double acting hydraulic rams 111, one located forward of the body 13, and the other located rearward of the body 13. When unloaded, the body 13 is supported from direct contact with the chassis 15 15, above and on the chassis 15 by the elevating mounts formed by four square shaped plate members 113 in alignment with two further plate members 115 extending laterally across the base of the body 13 proximal to the forward wall 71 and rearward wall 73 of the body 13. 20 The double acting rams 111 can in use be maintained under pressure, in a loaded condition, to slightly elevate the body 13 off the chassis, if required. If, when the body is not loaded, the double acting rams 111 are maintained under pressure to slightly elevate the body 13 off the chassis 15, the four square shaped plate members 113 in alignment with two further plate members 115 will 25 not come into contact until such time as load weight increases as the body is loaded with bulk solids. The base 67 is formed from 8mm thick HARDOX T M 450 Brinell hardness high impact steel sheet, while the forward wall 71, rearward wall 73, side wall 75 and 30 coaming 89, and door 95 and coaming 103 are formed from 4mm thick
HARDOX
T M 450 Brinell hardness high impact steel sheet. The body runner 93 is formed from 5mm thick HARDOX T M 450 Brinell hardness high impact steel sheet. The HARDOX T M sheet is a resilient deformable steel sheet that will flex under impact and load, but under designed load conditions will return to its 35 original shape. HARDOX TM sheet is manufactured by SSAB Oxel6sund AB. The forming of the body of this material provides wear resistance and impact resistance against permanent deformation of the body during loading operations. 14 5 The forming of the side walls, door and attached coaming of this material provides significant benefit in terms of resilience and resistance against permanent deformation. In particular, the forming of the coaming of the same material as the sheet material of the longitudinal door and longitudinal side ensures that the risk of permanent deformation of the sides of the trailer is 10 minimized. In particular, it avoids the problem noted by the inventors in prior art trailers having coaming of RHS section mild steel, where the coaming yields under impact, and does not spring back into shape, resulting in a permanent bend that can result in the trailer body width exceeding required specifications and perhaps road regulations. 15 It will be noted that the side wall 75 and the door 95 consist of, between their forward and rearward extents, single sheet thickness sheet material forming the side wall 75 and door 95 respectively, each of the side wall 75 and the door 95 having coaming 89 and 103 respectively, along their upper longitudinal extents. 20 The side wall 75 and the door 95 are lacking lateral/tranverse bracing between their forward and rearward extents, which provides improved appearance, and reduced tare and improved aerodynamic properties of the trailer, which lead to improved fuel efficiency, in use. 25 The plate members 113 are formed of 25mm thick mild steel and are fillet welded to the chassis 15. The two further plate members 115 formed of 12mm thick mild steel, and include slots 117 through which plug welds are made to the underside of the base 67. The two further plate members 115 are also fillet welded to the underside of the base 67. As can be seen in figure 7, the forward and rearward 30 hinges 109 mount to respective two further plate members 115 on check plates 119. A 12mm spacer plate 121 is provided to align the central hinge 109 with the two other hinges. Figures 7 and 8 show a longitudinal vertical cross section through section A-A of 35 figure 1. Figure 7 shows such a cross section in the unloaded condition, while figure 8 shows the loaded condition, with a load shown as 123. In figure 8, deflection of the base 67 under the weight of the load, so that the base 67 15 5 contacts the top of the flanges 37 and 53 of the chassis rails 31, 33, and cross members 41, 43, and 45 respectively. To provide silencing against noise that will result from such contact, the relevant flanges are provided with padding in the form of 25mm thick rubber strip which is fixed by adhesive to the relevant flanges. 10 The sequence of unloading the trailer is shown in figures 1 through 3 and 4 through 6, although in use it would be expected that the trailer will be connected to a prime mover or dolly, and not standing on its landing legs for such an operation, when carrying a load. 15 Referring to figures 11 to 13, the second embodiment is illustrated. In this embodiment, the body runner 93 present in the first embodiment is omitted. In order to achieve the required strength, the side wall 75 is formed with a curvature 125, to meet the plane of the base 67. The side wall meets the plane of the base 20 67 in overlapping manner with a longitudinally extending overlap 126. The base 67 and the side wall 75 are fillet-welded on the inside 127 of the body 13 and on the outside 129 (ie both sides of the sheet material). The base 67 and side wall 75 are also welded to the forward wall 71 and the rearward wall 73. 25 Referring to figures 14 and 15, the third embodiment is illustrated. This differs from the second embodiment in that instead of a smoothly curving side wall 75, the side wall 75 and base 67 are of unitary construction (formed from a single sheet of 4mm thick HARDOX T M sheet), and are formed with six longitudinally extending creases/bends 131, formed in a press brake, in order to provide 30 improved rigidity. The trailers of the first and second embodiments are designed to receive an initial impact of a two tonne rock impacting an area of 1 m 2 dropped from a height of 1.5m by a loader into the body, in a central position, without damage 35 occurring to the chassis. In practice, the initial load is more likely to be ten tonnes of ore comprising a number of small rocks dropped from a loader bucket, impacting an area of 2.5m 2 to 3m 2 . With subsequent loads during the loading 16 5 operation, as further material is dropped on top, the energy is spread over a larger area, so it is of no concern that the base 67 of the body 13 begins to come into contact with the chassis 15 as loading continues. As the elevating mounts formed by four square shaped plate members 113 in alignment with two further plate members 115 are in close proximity to the forward wall 71 and rearward 10 wall 73 of the body 13, it is unlikely that any initial load dropped into the body 13 will impact in the region of the elevating mounts. Thus the energy from the initial impact of any loading operation will be dissipated through the flexing of the base 67 within the space provided between the base 67 and the relevant web portions forming the chassis 15. 15 The invention provides a much reduced tare when compared with conventional trailers of the same capacity. This allows the load carrying capacity to be increased to the maximum allowable for transport by road, offering improved efficiency and associated productivity gains. The trailer of the first embodiment 20 has an overall length of 9.9m, width of 2.5m, and height of 3.1m. The internal dimensions for the body are length 5.9m, width 2.25m (narrowest) and 2.4m (widest), and height 1.2m. The total load (iron ore) of the trailer as illustrated is 33.8 tonnes for on-road use, and 40 tonnes for off-road use. The unladen tare is 9.2 tonnes and gross tare for on-road use is 47 tonnes (including 4 tonnes for the 25 dolly). Due to the structural differences in the second and third embodiments, the unladen tare would be slightly less in these embodiments than that of the first embodiment. It should be appreciated that the scope of the invention is not limited to the 30 particular embodiment disclosed herein. Thinner material may be used for the body, for applications where a hard initial impact is not expected during loading. For example, trailers designed to carry fine particulate material may be constructed of 3mm plate. 35 17