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A DUMP BODY FOR A MINING HAUL TRUCK

TECHNICAL FIELD

[01] The present invention is directed to a dump body (truck tray} of special design.

BACKGROUND

[02] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common genera! knowledge.

[03] A mining haul truck is a very large piece of equipment used to remove overburden, rock, dirt, coal, and other payloads. Caterpillar Inc. is an example of a company that manufactures a range of such trucks and details can be found of their website

[04] http://\Aaw.cat.com/equipment/off-highway-trucks/mining-truc ks. Figure 12 also shows a typical PRIOR ART mining haul truck.

[05] These trucks typically weigh, when loaded, between 100-650 tons and can carry a payioad of between 100-400 tons. The truck can be loaded by a power shovel or hydraulic excavator (for reference, known as the loading toot). Figure 13 illustrates a typical PRIOR ART mining truck being filled by a power shovel. The loading fool can have a capacity of up to 100 tons per load.

[06] The present invention is directed to improvements to the dump body of the haul truck. The dump body is the upper tray in which the payioad is collected.

[07] Ciearly, because of the very large amount of payioad to be carried by the dump body, the dump body itself requires specialized manufacture. Typically, the dump body will have a floor which can have a width of between P(

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5-10 m, a pair of opposed upwardly extending sidewalls, a front waif which extends upwardly, and a somewhat horizontal canopy which protects the driver's cab. The rear of the dump body is open. The dump body is pivoted and can be raised to dump the contents from the hauf truck. Figure 5 illustrates a mining haul truck with the dum body in the raised (dumping) position.

[08] US 20130043701 discloses a floor design fo a dump body and describes the forces and strains placed on the floor.

[09] One disadvantage with conventional dump bodies is their weight. In order to make the body strong enough to withstand the forces of payload being dropped into the body, the body is made of thick cast or steel pieces and has a large number of reinforcing beams, struts and the like. Figure 13 at least illustrates a PRIOR ART body illustrating large number of heavy beams welded to the steel walls of the body. There would be an advantage if it were possible to manufacture a body of reduced weight while maintaining acceptable strength and increasing payload capacity but stili staying within the Original Manufactures GVM. There would be an advantage if it were possible to manufacture a body with less man hours by clever redesign of various parts,

[10] Another disadvantage with conventional dump bodies is that care must be taken that the loading tool does not strik the sidewalls of the dump body. However, it is generally not acceptable to have the loading tool dumping the contents into the dump body from a great height as this can damage the dump body floor. Thus, the loading too! is generally positioned close to the sidewalis when dumping payload into the dump body. The loading tool needs to be lifted sufficiently to clear the sidewalls at each dump cycle. This can lengthen the time taken to fill the truck body with payload, as several shovel loads are required to fill the truck body.

[11] There would be an advantage if it were possible to design the body in such a way to reduce strike damage and to reduce the lift distance of the PC

3 shove!, thereby reducing damage to the truck body, and also to improve the cycle time of loading of the truck and to lower operational costs.

[12] There would be an advantage if it were possible to design the sidewails of the dump body in such a manner to reduce the weight of the sidewails without appreciably compromising on the payioad able to be supported by the dump body.

[13] Another part of the dump body is the headboard which is sometimes also called the canopy. Figure 12 and figure 13 illustrate PRIOR ART trucks illustrating a headboard (e.g. 25 in figure 12) which functions to protect the driver's cabin, the engine components, the stairs and the various other parts on the front of the truck. The headboard clearly needs to be made of strong steel and is typically reinforced underneath by strong steel beams. Such beams are illustrated in figure 12 and also in the PRIOR ART body illustrated in figure 14 (see reference numeral 31 ), This construction, while being strong, also adds a great deal of weight to the body and can cause a significant cantitevering effect at the joining area at the base of the canopy and the top of the body creating cracking.

[14] The primary purpose of the headboard is to protect the cabin etc. and not to carry a load. The payioad is supported by the main bod part, if payioad is accidentally dropped onto the headboard, it can roll off the front edge and damage the front parts of the truck and potentially cause personnel injury. It is known to provide a small upstanding lip, but large rocks that find themselves on the headboard are able to roll over the upstanding lip and down onto the unprotected parts of the truck. There would be an advantage if it were possible to design the headboard to be lighter, sufficiently strong, be at least partially self-supporting, and have less underbearer beams.

[15] Another disadvantage is that it is difficult to remove rocks or other payioad that are accidentally placed or find their way onto the headboard. There would be an advantage if it were possible for the headboard to be P(

4 somewhat "self-cleaning'' which means that if payload (rocks etc.) is accidentally dropped onto the headboard, it can be removed relatively easily and in such a manner to not damage the front of the truck.

[16] Another disadvantage with conventional dump bodies is the amount of reinforcing in the sidewalls which can add to the weight and fabrication cost and time. Also, the weld joins and other joins between the side wall reinforcing and the headboard are subject to stresses that can cause cracking. There would be an advantage if it were possible to reduce fatigue/cracking and the like in this area of the dump body and there would be an advantage if it were possible to reduce weight and/or fabrication costs and/or time.

[17] Another disadvantage with conventional dump bodies is the amount of reinforcing (and therefore the weight, cost and fabrication time) in the front wail of the dump body. The front wall is the upstanding wall between the floor of the dump body and the headboard and which is typically positioned behind the cabin. Figure 14 typically illustrates the amount of steel reinforcement required in the front wall of a PRIOR ART dump body. There would be an advantage if it were possible to reduce the weight and the amount of steel reinforcement in this part of the dump body, which may thereby also reduce the manufacturing cost and time.

[18] Another disadvantage with conventional dump bodies is the amount of reinforcing required underneath the floor of the dump body in order to support the stresses and weight of the payload during loading, transportation and dumping of the payload. Typically, large and numerous steel beams are positioned underneath the floor or the floor is cast or manufactured with large numbers of reinforcements. The arrangement is typically in the form of a box section frame which adds a large amount of weight to the dump body and appreciably increases the fabrication time and cost. There would be an advantage if it were possible to provide some form of support for the floor which would be strong, reduce the weight and lower the fabrication time and cost. Ρί

[19] !t is an object of the present invention to provide a dump body for a truck, and typically an off-road mining haui truck which can have a reduced weight while maintaining or even increasing payioad capacity and strength.

[20] !t is another object of the present invention to provide a dump body for a truck, and typically an off-road mining haul truck and which may overcome at least some of the above-mentioned disadvantages or provide a useful or commercial choice in the marketplace.

SUMMARY OF THE INVENTION

[21] According to a first aspect of the present invention there is provided a dump body for a mining haul truck, the dump body comprising a floor, a pair of upstanding sidewalis, a front wall, a headboard, and a tail portion extending between the sidewalis and extending from a rear of the floor, the dump body having an open rear, wherein each sidewaii has an upper edge, the upper edge comprising a first substantially level edge extending between the front wall and adjacent an imaginary line extending from a dump point pivot, and a second inclined edge extending between adjacent the dump point pivot and terminating at the tail portion.

[22] According to a variation of the first aspect of the present invention ( and depending on the size and model of the truck) there is provided a dump body for mining haui truck, the dump body comprising a floor, a pair of upstanding sidewalis, a front wall a headboard, and a tail portion extending between the sidewalis and extending from a rear of the floor, the dump body having an open rear, wherein each sidewaii has an upper edge, which comprises a first substantially level edge extending from the front wall and a second inclined edge extending from the first edge and terminating adjacent the tail portion, the length of the second edge being between 40-60% of the length of the first edge. PC

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[23] These versions of the invention can be called the "reversed curved rear sidewa!i" or "concave rear side wa!P.

[24] The second inclined edge typically slopes downwardly towards the rear open end of the dump body. In this aspect of the invention, the second inclined edge is much more pronounced and longer than in a conventional dump body - for instance as illustrated in Figure 13. Instead of the sloping edge being a small fraction of the total length of the upper edge of each sidewa!l, the sloping edge is a significant portion of the total length, and can be between 40-50% of the total length.

[25] One advantage of this arrangement is that it can reduce the total weight of the dump body by up to 600-700 kg without appreciably reducing the payload.

[26] The dump point pivot is the pivot point or pivot axis about which the dump tray rotates when being lifted and lowered. An imaginary line (see for instance "X" in figure 5) extending from the dump point pivot towards the upper edge of the side wall will be at or adjacent the position where the first substantially level edge meets with the second inclined edge. This will be described in greater detail below. It can be seen that the second inclined edge constitutes a significant proportion of the total edge length of the sidewafts.

[27] The upper edge and particularly the first edge can include detachable hungry boards and is meant to include the uppermost free edge or "rim" of the sidewa!l.

[28] Another advantage of the first aspect and in a variation of the first aspect of the present invention is that there is now a larger amount of bucket clearance for the loading tool. Thus, with this aspect of the present invention, the loading too! does not need to raise and lower the bucket as much as previously required which can improve the speed of filling the dump body Ρί

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(the fining cycle), can reduce striking damage to the dump body by loading tool and will also reduce wear and tear and costs on the dump body.

[29] According to a second aspect of the present invention there is provided a dump body for mining haul truck, the dump body comprising a fioor, a pair of upstanding sidewalls, a front wall and a headboard, the dump body having an open rear , the headboard being of special design and comprising a first inclined face inclining towards the floor of the dump body, a second inclined face inclining towards one side of the dump body, a third inclined face inclining towards the other side of the dump body, and a top portion.

[30] The second aspect of the present invention can be called the "angled headboard" aspect.

[31] The headboard is also known as the canopy and functions, inter alia, to protect the drivers cabin.

[32] The headboard is preferably formed from a single sheet which is pressed into the required configuration. Alternatively, the headboard may comprise separate sheet members welded or otherwise attached together, The headboard wiil typically be made of steel sheet/panel and will typically have a thickness of between 3-8mm.

[33] The first inclined face may be angled downwardly at between 3- 20° and preferably about 7°. A benefit of this is that any rocks, payload etc. that fail on this part of the headboard wili siide/roil back into the main body portion of the dump body and will not remain on the headboard.

[34] The first inclined face preferably extends from the upper end of the front wall and from one sidewall to the other sidewail.

[35] The second and third inclined faces may comprise "side faces" to direct any rocks etc. falling on the side faces off the side of the truck and onto the Ρί

8 ground. These faces may be angled down at between 3-10° and preferably at about 5°.

[36] The top portion may comprise a substantially flat face which is not very large. Alternatively, the top portion may comprise an apex portion of the various faces, or a domed portion or another inclined portion.

[37] The front part of the headboard may comprise an upstanding skirt portion.

[38] An advantage of the angled one piece design of the headboard is that the headboard is "free standing" and has appreciable inherent strength to deflect rocks etc. which reduces the need to fit numerous large and heavy bearers under the headboard to support the headboard as is required with known PRIOR ART dump bodies of the type illustrated at least in in figure 12 and figure 13

[39] Suitably, the angled headboard of this aspect of the present invention can be reinforced by a fewer more light weight structural members and preferably only a pair of T-section structural members which will substantially reduce the cantiievering effect. This will be described in greater detail below. There may be some mining applications where the conditions are severe and the material being loaded is large, and in these conditions additional T sections may be added on either side of the existing centr T sections for additional strength. Figure 32A in figure 11 Illustrates this variation.

[40] According to a third aspect of the present invention there is provided a dump body for mining haul truck, the dump body comprising a floor, a pair of upstanding sidewails, a front wall and a headboard, the dump body having an open rear, wherein the front wall is reinforced by a plurality of spaced apart upright members at least one adjacent said pair of upright members being interconnected by angled bracing members.

[41] Suitably, the bracing members comprise T sections. P(

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[42] Suitably a pair of angled bracing is provided to interconnect the said adjacent pair of upright members. Suitabl the angles bracing is in an "X" type configuration.

[43] Suitably at least two pairs of adjacent upright members are braced. Suitably, these include end upright members.

[44] The upright members may be separate members welded or otherwise attached to the front wall, or may be cast into the front wall, or may be a combination of both.

[45] After much research and experimentation it has now been found that it is possible to reduce the weight of the front wall of the dump body without appreciably reducing the strength by a particular type of reinforcing as described above. Thus, instead of conventional reinforcing, an example of which is illustrated in figure 14 and which comprises a multiplicity of large and heavy steel beams in a vertical and horizontal "boxlike" configuration, it has now been found that an acceptable strength and reinforcing can be provided with less upright members but where at least one pair of adjacent spaced upright members are braced, suitably by T section bracing members, in an X like configuration. Notwithstanding the long use of large haul trucks and the continual desire to reduce truck weight ( which can reduce fuel consumption tyre wear and increase haul truck cycle times), there has been no teaching or realization that the particular type of front wall reinforcement as described above can reduce weight while maintaining stiffness and strength, and can reduce fabrication time.

[46] According to a fourth aspect of the present invention there is provided a dump body for mining haul truck, the dump body comprising a floor, a pair of upstanding sidewails, a front wall and a headboard, the dump body having an open rear, wherein each side wall has a side wall cross bracing member extending from the headboard to a lower end of the sidewall and adjacent the open rear of the dump body. Ρί

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[47] This fourth aspect of the invention can be called the "side wa!l cross bracing" aspect.

[48] After much research and experimentation, it has been found that good strong bracing of the side wa!f and particularly connection of the side wall to the headboard can be achieved with a side wall cross bracing member. The side wall cross bracing member has one end attached to or relative to the headboard extreme front and at or adjacent an upper edge of the side wall and at the other end is attached to or relative to a lower end of the side wall and adjacent the open rear.

[49] In contrast, a typical conventional dump body as illustrated in figure 12 has a large horizontal bracing members or (as illustrated in figure 14) has large vertical bracing members. However, prior to the present invention, the advantage of an angled cross bracing member was not realized,

[50] An advantage of the cross bracing member according to this aspect of the present invention is that it can strongly tie the front of the dump body to the rear of the dump body. It can also provide a strong connection to the headboard to minimize fatigue and cracking between the side wall and the headboard.

[51] Suitably, the cross bracing member comprises a steel beam. The steel beam can provide appreciable stiffening of the sidewall yet reducing the weight.

[52] According to a fifth aspect of the present invention there is provided a dump body for mining haul truck, the dump body comprising a floor, a pair of upstanding sidewails, a front wall and a headboard, the dump body having an open rear, the floor being supported by a pair of spaced apart longitudinal chassis rail beams.

[53] Suitably, each rail beam comprises a T section beam. P(

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[54] Suitably, the chassis rail beams are braced relative to each other by diagonal raii bracing ties. Suitably, a pair of ties is provided in an X type configuration.

[55] After much research and experimentation, it has now been found that the use of a pair of spaced apart longitudinal chassis rail beams and especially in the form of steei T-sections provide strong fatigue resistant connections with floor bearers of the floor, is stiff and lightweight, and provides an efficient use of steel. The chassis rail bracing also provides acceptable stiffness while reducing weight.

[58] This is in contrast to many dump bodies where the floor is reinforced by heavy complicated box section chassis components which increase fabrication time, fabrication costs and weight.

[57] Suitably, the floor includes a plurality of laterai floor bearers. The floor bearers may be cast into the floor or formed separately. Suitably, the floor bearers extend from a side end of the floor and towards a said rail beam. Suitabiy, the floor bearers do not extend between the rail beams.

[5θ] Thus, instead of the complicated and heav arrangement of existing dump bodies which have a multiplicity of transversely extending floo beams extending entirely along the underneath of the floor from one side end of the floor to the other side end of the floor, the present reinforcing arrangement can reduce weight by providing a pair of longitudinal rail beams and laterall extending floor bearers which extend only from a beam to a side edge of the floor but not entirely across the floor. Instead, the diagonal rail bracing ties are provided between the beams and this arrangement provides acceptable stiffness and strength while substantially reducing fabrication costs, fabrication time and weight. This will be described in greater detail below.

[59] However, in some mining applications where the mining conditions are severe and the material being loaded is large, a set of T section cross PC

12 members may be used to take the impact of the larger than what would be considered to be normal sized material. Iron ore mining may constitute severe conditions and this modified style of floor bearers are still light and very strong can wili support the headboard and floor much more with impact loading, for instance to limit wear and tear. Figures 45A, 46A and 48A in figure 11 illustrate this variation.

[60] The dump body may include a tail portion which may be angled slightly upwardly to retain payload especially when the truck is moving along an incline. The tail portion can also function to increase ground clearance when the dump body is tipped upwardly.

[61] It is expected that the above aspects of the invention can be used individually or in combination to provide improvements to the dump body of a haul truck. It is also anticipated that a dump body made according to the above aspects of the present invention can be fabricated more quickly (estimated at 300 less man hours than a conventional dump body) and at less cost.

BRIEF DESCRIPTION OF THE DRAWINGS

[62] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The

Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows.

[63] Figure 1. Illustrates a mining haul truck having a dump body and including embodiments of various aspects of the present invention.

[64] Figure 2. Illustrates the mining haul truck of figure 1 from a different angle.

[65] Figure 3. illustrates a front view of the truck.

[66] Figure 4. Illustrates a rear view of the truck.

[67] Figure 5. Illustrates the truck in a tipping position. Ρί

[68] Figure 6. Illustrates a side view of the truck.

[69] Figure 7. Illustrates a view of the dump body from the rear.

Γ70] Figure 8. Illustrates a below view of the dump body.

[71] Figure 9, Illustrates a close up of the bracing ties.

[72] Figure 10. Illustrates a dose up of the bracing of the front wall

[73] Figure 11. Illustrates a dump body for extreme mining conditions.

[74] Figure 12. Illustrates a PRIOR ART haul truck with a dump body.

[75] Figure 13. Illustrates a PRIOR ART haul truck being filled by a power shovel.

[76] Figure 14. Illustrates a PRIOR ART dump body.

[77] Figure 15. Illustrates another PRIOR ART haul truck from the rear and particularly illustrating the numerous heavy transverse beams extending under the floor and which extend from one side of the floor to the other side of the floor.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[78] Referring initially to figures 1-6 there is illustrated a mining haul truck containing preferred embodiments of various aspects of the present invention. The mining haul truck 10 comprises a large dump body 1 1 , a driver's cab 12 a front engine 13 and ground wheels 14. The truck can also contain axles, differentials, electric generators, electrical wheel drive motors and frame components. Figure 6 provides various dimensions of the truck to illustrate the size of the truck but it should be appreciated that these dimensions are according to a preferred embodiment only and need not be limiting to the invention. However, the dimensions do clearly illustrate that these trucks are of large size and large capacity. Typically, a dump body 11 can accommodate the payload of between 100-400 tons. The truck itself will typically have a combined weight of between 100-650 tons. The cost of such trucks is in the order of $2,000,000 to $8,000,000

[79] In figure 1 , the dump body is filled with a payload 50 typically comprising mining overburden, in figure 2, the dump body is empty. Ρί

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[80] In the non-limiting embodiment of the present invention, the dump body can have a length from the front of the headboard to the rear of the body of about 13 meters, the height of the headboard from the ground may be about 7 meters, the distance between the front and rear wheels of the vehicle may be about 5.9 meters, the distance between the rear wheel axle and the rear of the dump body may be about 4 meters, the height of the rear of the body from the ground may be about 5.1 meters, the degree of travel when the body is tipped may be about 51°, and the height of the front of the body from the ground when in full operational tip may be about 13 meters. Off course, these values may vary depending on the type of vehicle used and the type of dump body used.

[81] The present invention is directed to improvements to the dump body 11. Dump body 11 comprises the following main components: a floor 15 which can have a width of between 5-10m and a length of between 9-10 m, opposed sidewalls 16, 17, a front wall 18 which extends upwardly from floor 15 and between sidewalls 16, 17, and a headboard (also known as a canopy) 19 which extends over the driver's cabin 12. The rear 20 of dump body 1 1 is open to ailow payload to be dumped when the dump body is raised (see figure 5),

[82] According to the first aspect of the present invention, (the reverse curved rear side wail aspect) the dump body 1 1 is as described above and contains particularly shaped sidewalls 16, 17. Specifically, and initially referring to figure 2, each sidewa!l 16, 17 is provided with an upper edge which comprises two parts being a first substantially level edg 21 , and a second inclined edge 22 which slopes downwardly towards the open rear part 20 of the dump body 1 1. The particular shape of the inclined edge is such that the second inclined edge 22 comprises between 40-60% of the total edge length. That is, rather than the second inclined edge being a small part of the upper end of the side wall, the second inclined edge can constitute almost half of the side wall. This is also perhaps better illustrated in figure 6 and figure 5 which more dearly shows that the second sloping edge portion 22 constitutes approximately half the total length of the upper P(

15 end of the side wall {that is the combination of edge 21 and edge 22). The first substantially level edge 21 extends from the front wail 8 of the dump bod and terminates approximately at the dump point pivot 23 which is best illustrated in figure 5. By this is meant that an imaginary line "X" extending from the dump point pivot 23 and substantiaily at right angles to edge 21 wiil be the approximate point where edge 21 and edge 22 meet. The first substantially level edge 21 will usually be substantially horizontal but may also be a little inclined but much less so than the second edge.

[83] The second inclined edge 22 typically slopes downwardly towards the rear open end 20 of the dump body, in this aspect of the invention, the second inclined edge is much more pronounced and longer that a conventional dump body, for instance that illustrated in Figure 13. Instead of the sloping edge being a small fraction of the total length of the upper edge of each sidewatl, the sloping edge is a significant portion of the total length, and can be between 40-50% of the total length. It should be realized that this can depend on the model and size of the truck.

[84] In this aspect of the invention, it is preferred that the open rear 20 of dump body 11 is provided with an upwardly curved angled tail portion 24.

[85] It is found that this particular design of the sidewails can reduce the weight of the dump body by between 600-700 kg of steel without compromising on the payload that the dump body can support. Another advantage is that there is less sidewall for the loading too! to strike. To explain, referring to the PRIOR ART arrangement illustrated in figure 13, the relatively high sidewails required the loading tool 51 to be raised and lowered by a greater distance than is the case with the particularly designed sidewaiis of this aspect of the present invention. This improves the filling cycle time. Additionally, there is less chance of the loading tool striking the sidewails of the dump body 1 as the sidewails are less pronounced.

[88] Referring to at least figure 2, figure 7 and figure 8, there is illustrated the second aspect of the present invention (angled headboard aspect) which Ρί

16 is a particularly designed headboard 19. Instead of the headboard being substantially flat (see for instance PRIOR ART headboard 25 illustrated in figure 12 and figure 13), the headboard has various profiled surfaces.

[87] Specifically, and referring to figure 2 at least, the headboard has a first inclined face 26 inclining towards the front wall 18 and the floor 15 of the dump body, a second inclined face 27 inclining towards one side of the dump body, a third inclined face 28 inclining towards the other side of the dump body, and a top portion 29.

[88] The headboard 19 is also known as a canopy and functions, inter alia, to protect the driver's cabin.

[89] The headboard can be formed from a single sheet of steel which is pressed into the required configuration.

[90] The first inclined face 26 is angled downwardly at about 7°. A benefit of this is that any rocks, pay!oad etc. that fall on this part of the headboard will slide/roll back into the main body portion of the dump body and will not remain on the headboard. The first inclined face extends from the upper end of the front wall 18 and from one sidewail 16 to the other sidewall 17.

[91] The second 27 and third 28 inclined faces comprise "side faces" to direct any rocks etc. failing on the side faces off the side of the truck and onto the ground. These faces are angled down at about 5°. The top portion comprises a substantially flat face which is not very large.

[92] The front part of the headboard is surrounded by an upstanding skirt portion 30 which functions as a barrier to prevent or reduce the possibiiity of pay!oad falling off the front of the headboard and damaging the railings and other parts in the front of the truck.

[93] The shape of the headboard means that any payload accidentally being dropped in this area will either slide back info the main body portion of PC

17 the dump body (because of inclined face 26) or will slide off side faces 27 and 28 to the sides of the truck. The top portion 29 is relatively small and it is unlikely that it will be able to support an undesirable amount of payload.

[94] The single piece angle headboard is made of steel and is self- supporting and is able to withstand impact of rocks and payload due to the shape of the headboard. Thus, there is less need to provide heavy protective support beams underneath the headboard as is the case with some existing known dump bodies for instance as illustrated in figure 12 and figure 14. Specifically referring to figure 12 it can be seen that the headboard 25 needs to be reinforced by numerous large and heavy beams 31 ^' .

[95] In contrast, and referring to figure 8, the underneath of headboard 19 can be sufficiently reinforced by a pair of structural members 32 which are in the form of T-sections. Thus, instead of requiring multiple heavier steel box section, sufficient reinforcement can be provided by a pair of T sections 32. These sections are stiff and lighter than box section or solid steel beams, reduce fabrication time and provide an efficient use of steel.

[36] A third aspect of the invention is directed to a redesign of the front wal! of the dump body in order to provide strength reduce weight, improve fabrication time and reduce fabrication costs. This aspect of the invention is best illustrated at least in figure 8. in this third aspect, the front wall 8 is reinforced by a plurality of spaced apart upright members 33 at least one adjacent said pair of upright members being interconnected by angled bracing members 34. In the particular embodiment, the front wall 18 is reinforced by four upright members 33 comprising a pair of upright edge members and a pair of intermediate upright members. These members may comprise steel beams or castings. In the particular embodiment illustrated in figure 8, two sets of front wall cross bracing is provided by the angled bracing members 34. The bracing members 34 comprise T sections which are stiff yet light weight and can reduce fabrication time. The bracing members extend between one of the edge members and an adjacent P(

18 intermediate upright member. The cross bracing functions to tie the front wali and side wail together.

[97] After much research and experimentation it has now been found thai it is possible to reduce the weight of the front wall of the dump body without appreciably reducing the strength, by a particular type of reinforcing as described above. Thus, instead of the conventional reinforcing, an example of which is illustrated in figure 13 and which comprises a multiplicity of large and heavy steel beams in a vertical and horizontal "boxlike" configuration, it has now been found that an acceptable strength and reinforcing can be provided with less upright members but where at least one pair of adjacent spaced upright members are braced by T section bracing members in an X like configuration. Notwithstanding the long use of large haul trucks and the continual desire to reduce truck weight and fabricating costs (which can reduce fuel consumption, tyre wear and haul truck cycle times), there has been no teaching or realization that the particular type of front wall reinforcement as described above can reduce weight while maintaining stiffness and strength, and can reduce fabrication time.

[98] A fourth embodiment of the invention (the side wall cross bracing aspect) is best illustrated at least in figure 2, figures 5-6, and figure 8. In this embodiment, each side wall 16, 17 has a side wali cross bracing member 35 extending from the headboard 19 to a lower end of the sidewall and adjacent the open rear 20 of the dump body.

[99] The side wail cross bracing member 35 has one end 36 attached to or relative to the headboard and at or adjacent an upper edge of the side wall, and has the other end 37 attached to or relative to a lower end of the side wall and adjacent the open rear. Cross bracing member 35 comprises a strong steel beam having a height of about 400 mm and a thickness (depth) of about 200 mm and a suitable length depending on the length of the dump body. The top of the cross bracing member extends into the headboard region 19 and provides a strong connection to the headboard to minimize P(

1 fatigue and cracking in this area which can be a problem with other types of PRIOR ART dump bodies,

[100] Referring to figure 8, the other end of cross bracing member 35 is attached to a transverse beam 38 which extends across and under floor 15. ft is found that the cross bracing member 35 provides sufficient stiffness to the side wall without the requirement of multiple large and heavy horizontal or vertical reinforcing beams, instead, if an additional horizontal beam (e.g. 39 in figure 2 is present, this beam can be smaller and more lightweight. This is in contrast to the PRIOR ART dump body illustrated in figure 14 which illustrates a large number of vertical beams in the side wail or the PRIOR ART dump body illustrated in figures 12, 13 and 14 which illustrate very large and heavy horizontal and interconnecting substantially vertical beams.

[101] A fifth aspect or embodiment of the present invention is directed to improvements in the bottom support of the floor 15 of the dump body 11. Figure 8 and figures 9-10 best illustrate this embodiment of the present invention. In this particular embodiment, the floor is supported by a pair of spaced apart longitudinal chassis rail beams 40, 41 , which are in the form of T sections. The beams 40, 41 are spaced apart such that the imaginary central longitudinal axis of the floor extends between the beams. The beams 40, 41 are spaced apart by a distance of between 2-4 m. In the particular embodiment, each beam 40, 41 comprises a pair of short length beam members. Referring to figures 8 and 9, the beam comprises a first beam member 42 and a second beam member 43 which are in longitudinal alignment. The beams are interconnected to each other via a pair of strong steel side plates 44 which also form part of the dump point pivot 43. The pivot openings can be seen in figure 9 extending through each side plate 44. In an alternative, beam 43 may be further separated into two parts extending from each side of the transverse beam 38, The rail beams 40, 41 are braced by diagonal chassis rail bracing ties 45, 46 which extend only between beams 40, 41 and also between (rear) transverse beam 38 and a corresponding forward transverse beam 47. To provide further reinforcement to floor 15, the floor contains a number of floor bearers 48 which are best Ρί

20 illustrated in figure 8. These bearers 48 can be cast into floor 15 or formed separately and attached to the bottom of floor 15. The bearers 48 do not extend entirely across the bottom of the floor as is the case with some known dump bodies an example of which is illustrated in PRIOR ART figure 15 which illustrates transverse bearers 49 extending entirely across the bottom of the dump body floor and which add considerable weight, fabrication costs and fabrication time in the manufacture of the body.

[102] Instead, the bearers 48 according to this embodiment extend only from adjacent one side of the floor to adjacent one of the rail beams 40, 41.

[ 03] The combination of the longitudinal rail beams 40, 41 together with the bracing ties 45, 46 and the floor bearers 48 provide a good strong steel rigid floor to the dump body without the weight, fabrication costs and fabrication time of conventional existing dump bodies.

[104] The dump body according to the present invention may further include a taii portion 24 forming part of the open rear 20 of the dump body 11. The tail portion can be angled slightly upwardly to retain payload especially on grades, can reduce wear on the floor plate and can increase ground clearance when the dump tray is tipped upwardly this being best illustrated in figure 5,

[105] For heavy mining applications (iron ore mining) the body may require additional strengthening or alternative strengthening, this being illustrated in figure 1 1. in figure 11, the headboard contains strong spaced T sections 32A extending under the headboard and along the front of the body and connecting to the reinforcement under the floor with at least some of the beams preferably connected to the parallel rail beams. Additionaliy, the floor contains multiple strong T sections 48A extending to the side of the floor and sections 45A, 46A extending between the parallel rail beams. PC

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[106] The embodiments of the invention taken individually or in various combinations thereof provides an improved dump body that is strong, has a good payload capacity and can have a reduced weight compared to similar conventional dump bodies. Furthermore, the fabrication complexity can be reduced and the fabrication costs can be reduced and it is estimated that the time taken to fabricate the dump body can be reduced by about 300 man hours.

[107] !n compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term "comprises" and its variations, such as "comprising" and "comprised of" is used throughout in an inciusive sense and not to the exclusion of any additional features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

[108] Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms.

[109] Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention. Therefore, it should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention.