TECHNICAL FIELD

[0001] The present invention relates to safety measures for maintenance of heavy equipment and, more particularly although not exclusively, to maintenance procedures in the mining industry.

BACKGROUND

[0002] In many situations, such as in the recovery of heavy plant, for example in the mining industry, towing and to be towed heavy vehicles or plant, must be coupled together. Typically, this involves the use of coupling devices commonly known as “D” shackles. For the plant such a bulldozers and the very large earth moving vehicles employed in mining, these couplings of necessity are very large and very heavy.

[0003] In some situations, the coupling point to which a tow line or security line must be attached is at a level where a coupling needs to be lifted above shoulder height. Where the location precludes the employment of lifting machinery, health and safety restrictions on lifting the equipment present significant difficulties. In maintenance departments around Australia, personnel are required in pairs to fit a Safety Up Device (SUD) weighing 25-80kg to a Rear Dump Truck (RD) trays for maintenance to be undertaken. One to raise the shackle and sling and another to attach the pin and nut. It's cumbersome and time-consuming, the strength and dexterity required to fit them preclude some people from the task, and it has caused many workplace injuries.

[0004] When large earth moving trucks such as used in the mining industry and earth moving generally, require maintenance, the trays of these vehicles must be secured in the raised position to provide access and prevent the maintenance workers from being put at risk when working under a suspended load. These systems are sometimes called “SUD” which stands for “safety up devices” or “Tray retention systems”

[0005] Typically, this is achieved by securing the tray with a connection assembly extending between a connection point at the underside of the tray and a connection point on the chassis, or on the transaxle. A steel shackle, typically a “D” shackle is installed at the tray connection point and another shackle at the transaxle with a steel wire or sling/strop between the two. Sometimes the transaxle will have an attachment point with a pin that can be used.

[0006] Some of these trucks are so large that, even in the raised position, the connection point on the underside of the tray is well above shoulder height of a person. The weight of the steel shackle of sufficient strength to secure the enormous moment of the tray about its tilting axis, may be of the order of 15Kg, which for health and safety rules on some sites cannot, and may not be safely lifted above head height. When tilted, the area under the tray where the connection point has to accessed is too restricted to allow machinery such as a crane to be used to lift the shackle to the required height.

[0007] This requires the installation of the shackle to take place with the tray in its horizontal position so that a cherry picker of similar device can be brought into position, an operation both time consuming and expensive.

[0008] A further disadvantage of the steel shackle traditionally used in this application is that of stored energy in the shackle so that there is an inherent safety risk if the shackle should be stressed beyond its breaking limit.

[0009] Because of the difficulties associated with fitting steel shackles to the underside of the tipping tray, a common practice is to leave the shackle attached to the tray between services. But these are expensive items of equipment so to leave them attached to what may be a large number of trucks, is wasteful of resources and can lead to the items been damages when the truck goes about it’s normal operations. This is especially so for the very largest dump trucks which require a dual installation, thus four steel shackles and two steel wire or fibre slings.

[0010] It is an object of the present invention to provide a safety assembly which may be readily installed by a single operator with the tray in a raised position.

Notes

[0011] The term “comprising” (and grammatical variations thereof) is used in this specification in the inclusive sense of “having” or “including”, and not in the exclusive sense of “consisting only of’.

[0012] The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.

Definitions

[0013] Braided polymer material: in this specification braided polymer material refers polymer fibers braided together to form a bundle of fibers usually in elongate form. In particular forms the polymer fibers comprise ultra-high molecular weight polymer fibers. In further forms the fibres comprise ultra-high molecular weight polyethylene polymer fibers. In particular forms the fibres comprise UHMWPE fibres. In a further preferred form the fibres comprise an aramid, such as Technora by the Teijin Aramid a high strength polymer closely related to Kevlar, or Dyneema, one of the world’s strongest synthetic fibres which weight for weight is fifteen times stronger than steel. [0014] Tipping truck, rear dump truck and earth moving vehicle in this specification refer to very large, off-road trucks used in major earth works and in the mining industry.

SUMMARY OF INVENTION

[0015] According to one broad form of the invention there is provided safety assembly; the safety assembly including at least one shackle and a connecting line; the safety assembly securing the tipping tray of an earth moving vehicle into an inclined position for maintenance; the shackle comprising an assembly of polymer material and a transverse pin; the assembly of polymer material formed by splicing together ends of an initial length of polymer material to form an initial loop; longer opposing sides of the initial loop drawn together and secured side by side within an enveloping sheath to leave a secondary loop at each opposite outer end; the secondary loops engaging with the transverse pin. [0016] Preferably, the fibres are arranged in an assembly of multiple bundles spliced together to make one continuous loop.

[0017] Preferably, the coupling is formed by firstly providing a split at a first end of the assembly to form a first loop adapted to receive a transverse bone.

[0018] Preferably, the transverse bone is secured in the first loop by whipping.

[0019] Preferably, secondly a second end of the assembly is split to form a second elongate loop. [0020] Preferably, the second end of the assembly and the second elongate loop are folded back to pass under the bone and over the first loop to form the pull coupling.

[0021] Preferably, the shackle is formed from the continuous loop by a split at each end to form a first loop and a second loop.

[0022] Preferably, an assembly of a bolt and a first thimble is installed in the first loop and a second thimble is installed in the second loop.

[0023] Preferably, an outer end of the bolt is threaded to receive a locking nut; the nut securing the second thimble and second loop to the bolt when the second thimble and second loop are slid over the bolt to form a D shackle.

[0024] According to another broad form of the invention there is provided a coupling of a coupling and shackle combination; the coupling formed from an assembly of spliced together bundles of high molecular weight polymer fibres sheathed in braided polymer material.

[0025] Preferably, the assembly is split at a first end to form a first loop; the first loop adapted to receive a transverse bone secured in the first loop by whipping.

[0026] Preferably, the assembly is split at a second end to form a second elongate loop; the second elongate loop folded back to pass under the bone and over the first loop to form the assembly into a ring. [0027] According to another broad form of the invention there is provided a shackle of a coupling and shackle combination; the shackle formed from an assembly of spliced together bundles of high molecular weight polymer fibres sheathed in braided polymer material.

[0028] Preferably, the assembly is split at each end to form respectively a first loop and a second loop.

[0029] Preferably, an assembly of a bolt and a first thimble is installed in the first loop; a second thimble being inserted into the second loop.

[0030] Preferably, a lock nut assembled to a threaded outer end of the bolt secures the second thimble and second loop to the bolt when the second thimble is slid over the bolt to form a D shackle. [0031] According to another broad form of the invention there is provided a method of forming a coupling of a coupling and shackle combination; the method including the steps of: forming an assembly of high molecular weight into bundles to form a continuous loop, controlling shape of the continuous loop by sheathing the continuous loop with braided polymer material, providing at a first end of the continuous loop a first split to form a first loop adapted to receive a transverse bone, providing at a second end of the continuous loop a second split to form an elongated second loop, folding back the second end and the second elongated loop to pass under the bone and over the first loop to form the coupling.

[0032] According to another broad form of the invention there is provided a method of forming a shackle of a coupling and shackle combination; the method including the steps of: forming an assembly of high molecular weight into bundles to form a continuous loop, controlling shape of the continuous loop by sheathing the continuous loop with braided polymer material, providing a split at each end of the continuous loop to form a first loop at a first end and a second loop at a second end, inserting an assembly of a bolt and a thimble into the first loop and inserting a second thimble into the second loop, sliding the second thimble and second loop over the bolt, securing the second thimble and second loop on the bolt by a locking nut on a threaded outer end of the bolt to form the shackle.

[0033] According to another broad form of the invention there is provided a method of recovering a disabled item of equipment by a towing source; the method including the steps of: Attaching one of either a coupling or a shackle to a towing fixture of the towing source,

For a coupling in open condition, fitting an end with an elongate loop of the coupling ring through a first loop at a first end of a connecting cable,

Closing the coupling by folding the end with the elongate loop back and around a bone of the pull ring,

Attaching one of either a coupling or a shackle to a towing or recovery fixture of the disable item of equipment,

Fitting a second loop at a second end of the connecting cable to the coupling or the shackle, Applying sufficient tension to the connecting cable to move the disabled item of equipment and wherein each of the coupling and the shackle includes assemblies of bundles of ultra-high molecular weight polyethylene polymer fibre.

[0034] Preferably, the coupling includes a first loop formed at a first end of the assembly of polymer fibres; a bone inserted into the first loop secured in position by whipping.

[0035] Preferably, the elongate loop is formed at a second end of the assembly of polymer fibres.

[0036] Preferably, a length of the assembly of bundles of polymer fibres of the shackle is provided at each end with a loop.

[0037] Preferably, an assembly of a steel thimble and a steel bolt is inserted into a first of the loops; a steel thimble being inserted into a second of the loops.

[0038] Preferably, in a closed condition the thimble in the second of the loops is slid over an outer end of the bolt and a securing nut is fitted to a threaded end of the bolt.

[0039] According to another broad form of the invention there is provided a connecting cable connecting either one of a coupling or a shackle at each outer end of the connecting cable; the connecting cable formed of aramid polymer bundles spliced together and sheathed with an integral loop provided at each outer end; each of the coupling and shackle including assemblies of bundles of ultra-high molecular weight polyethylene fibres.

[0040] According to another broad form of the invention there is provided a method of lifting a load; the method including the steps of: fitting the load with a sling,

With a coupling in an open condition feed an end of the coupling with an elongate second loop around a lifting point of the sling,

Closing the coupling by folding the end with the elongate second loop back on itself to pass the elongate loop under a bone of the coupling and over a first loop,

Fitting an end of the closed coupling over a lifting hook of a lifting device and, Wherein the coupling is formed of an assembly of bundles of ultra-high molecular weight polyethylene; a first end of the assembly provide with a first loop for securing therein a bone; a second end of the assembly provided with a second elongated slot; the second end adapted for folding back to pass the elongate loop under the bone and over the first loop to close the coupling.

[0041] According to another broad form of the invention there is provided an assembly of bundles of fibres of ultra-high molecular weight polyethylene; the bundles forming a coupling wherein a first loop is provided at a first end of the assembly for securing therein a bone; an elongate second loop provided at a second end of the assembly; the elongate loop folded back on itself to pass under the bone and over the first loop to form the coupling and, wherein the bundles of fibres are chosen in number to define a desired breaking strain of the coupling.

[0042] According to another broad form of the invention there is provided an assembly of bundles of fibres of ultra-high molecular weight polyethylene forming a shackle; the assembly provided at each outer end with respectively a first loop and a second loop; an assembly of a metal bolt and a first metal thimble inserted into the first loop and a second metal thimble inserted into the second loop to form the shackle when the second loop is slid over the bolt and a locking nut is fitted to a threaded end of the bolt and, wherein the bundles of fibres are chosen in number to define a desired breaking strain of the shackle.

[0043] Preferably, the above method of constructing the coupling and shackle so as to provide a coupling and shackle of predetermined maximum breaking strain; said method comprising selecting the diameter of the fibres and selecting the number of laps of fibre forming the bundles so as to control the predetermined maximum breaking strain.

[0044] According to another broad form of the invention there is provided a pull ring formed from a length of braided polymer rope and a peg; the peg secured in first and second loops formed in the braided polymer rope; a main loop extends between and from the first and second loops; the pull ring locked into a closed ring by folding over the main loop to pass under outer portions of the peg and over those portions of the main loop adjacent the first and second loops.

[0045] Preferably, each of the first loop and the second loop is formed by threading a respective end of the length of braided polymer rope through an adjacent section of the rope.

[0046] Preferably, the peg is secured in the first and second loop by drawing the respective ends tight.

[0047] Preferably, the ends of the braided polymer threaded to form the first loop and the second loop are threaded through portion of the braided polymer rope adjacent to the opposite loop so as to draw the two loops closely together around the peg. [0048] According to another broad form of the invention there is provided a pull ring comprising first and second loops secured around a transverse peg; an elongate loop of braided polymer rope extending from and between the first and second loop; the elongate loop when folded back to pass under outer ends of the transverse peg and over portions of the elongate loop adjacent to the transverse peg, forming the pull ring.

[0049] According to another broad form of the invention there is provided a method of forming a pull ring from a length of rope and a transverse steel peg; the method including the steps of: folding the length of rope about a mid point of the rope to form two sections of the rope; folding inward each of the two sections approximate their respective mid points; attaching a needle fid to an outer end of the first of the two inward folded sections and threading the outer end through an adjacent portion of the first of the two inward folded sections to form the first loop; repeating the previous step for the second of the two inward folded sections to form the second loop; tightening the first and second loop around the transverse peg.

[0050] Preferably, the method includes the further steps of: reattaching the needle fid to the outer end of the first of the two inward folded sections and threading the outer end through a portion of the rope adjacent to the second loop; repeating the previous step of the outer end of the second of the two inward folded sections to thread this outer end through a portion of the rope adjacent to the first loop, so as to draw and lock together the first and second loop around the transverse peg.

[0051] Preferably, the method includes the further steps of: with a needle fid reattached to the outer end of the first inward folded section, threading the outer end through the centre of the second section of rope extending from the second loop from a point adjacent to the second loop to emerge proximate the mid point of the rope; repeating the above step for the outer end of the second inward folded section to thread it through the centre of the first section to emerge proximate the mid point of the rope; cutting each of the outer ends to a taper close to the sides of the rope; working each of the outer ends back into the centres of the two sections of the rope.

[0052] According to another broad form of the invention there is provided a safety assembly; the safety assembly including at least one shackle and a connecting line; the safety assembly securing the tipping tray of an earth moving vehicle into an inclined position for maintenance; the shackle comprising an assembly of braided polymer material and a transverse pin; the assembly of braided polymer material formed into a loop at each opposite outer end of a length of the braided polymer material; the loops engaging with the transverse pin.

[0053] In a particular preferred form the at least one shackle comprises a shackle constructed as described above.

[0054] Preferably, at least one shackle is attached to a connection point on an underside of the tipping tray rearward of a tilt axis of the tipping tray; the pin of the shackle passing through the connection point.

[0055] Preferably, a loop at a first end of the connecting line passes around the assembly of braided polymer material between the loops engaging with the transverse pin.

[0056] Preferably, a second shackle is connected to a loop at a second end of the connecting line; the second shackle connected to a connection point on a chassis or transaxle of the earth moving vehicle.

[0057] Preferably, a loop at a second end of the connecting line passes around a connection point on a chassis or transaxle of the earth moving vehicle.

[0058] Preferably, length of the assembly of shackle and connecting line when taut is equal to distance between the connection point on the underside of the tipping tray and the connection point on a transaxle of the earth moving vehicle.

[0059] Preferably, the assembly of polymer material is braided from initial lengths of bundles of polymer strands; outer ends of the polymer strands spliced together to form the assembly into a braided loop of material.

[0060] Preferably, the braided loop of material is stretched into an elongate loop; opposing longer portions of the loop drawn together and secured to lie side by side within an enveloping sheath to leave the loop at each opposite outer end of the assembly of braided polymer.

[0061] Preferably, a first thimble is secured in a first loop at a first outer end of the assembly of braided material and a second thimble is secured in a second loop at a second outer end of the assembly.

[0062] Preferably, each thimble is secured in a respective loop by lashing around regions of the braided polymer material extending from the thimbles.

[0063] Preferably, the pin comprises a shaft with a larger diameter head at one end and a projecting threaded section of smaller diameter at an opposite end.

[0064] Preferably, the first thimble is a free sliding fit on the shaft; location of the first thimble limited by the larger diameter head.

[0065] Preferably, the first thimble can be integral to the shaft or sliding [0066] Preferably, the second thimble is free sliding fit on the shaft; location of the second thimble limited by an inwardly projecting rim; internal diameter of the thimble at the rim being a free sliding fit over the threaded section.

[0067] Preferably, the second thimble is secured on the pin in use by a threaded locking element driven onto the projecting threaded section of the pin.

[0068] Preferably, the connecting line is formed of braided polymer material; the line initially formed as a loop of braided polymer strands by splicing ends of a length of the braided together; the loop then stretched and opposing longer portions of the loop drawn together side by side and enveloped within a sheath leaving projection portions to form loops at opposing outer ends of the sheath.

[0069] According to another broad form of the invention there is provided a method of reducing weight of a shackle component of a safety assembly securing a tilting tray of an earth moving vehicle in a raised position for maintenance; the method including the step of replacing a steel loop of a steel “D” shackle with braided polymer material; the braided polymer material extending between two thimbles; loops at outer ends of the braided polymer material passing around the two thimbles; the two thimbles engaging with a pin to form an equivalent “D” shackle.

[0070] According to another broad form of the invention there is provided a method of supporting a tilting tray of an earth moving vehicle in a raised position; the method including installing a shackle of a safety assembly to a connection point on an underside of the tilting tray when the tray is in the level position; a shackle of the safety assembly including a transverse pin and a loop of braided polymer material; the loop of braided polymer material extending from around two thimbles engaging with the transverse pin to form an equivalent “D” shackle; a connecting line of the safety assembly connecting the shackle to a connection point on a transaxle of the earth moving vehicle when the tray is in the raised position.

[0071] Preferably, the method includes the steps of: passing the loop of braided polymer material through a loop at a first end of a connecting line of the safety assembly, assembling a first thimble of the two thimbles onto a shaft of the transverse pin, passing the pin through an aperture of the connection point to position the first thimble on one side of the connection point, threading the second thimble of the two thimbles onto the shaft of the transverse pin to locate on an opposite side of the connection point, threading a locking element onto a threaded section of the pin adjacent the second thimble, bringing the tilting tray into the raised position, securing a loop at a second end of the connecting line to a connection point on the transaxle. [0072] According to another broad form of the invention there is provided a method of constructing a flexible element of a light-weight “D” shackle; the method including the steps of:

Forming a length of braided polymer material into an initial loop by splicing ends of the length of braided polymer material together,

Stretching the initial loop so as to bring opposing longer portions of the initial loop to lie side by side,

Enveloping the side by side longer portions within a sheath to leave a secondary loop at each outer end of the sheath,

Inserting a thimble in each secondary loop; the thimbles adapted for sliding engagement with a pin of the shackle to assume the form of a “D”.

[0073] According to another broad form of the invention there is provided a method of forming a connecting line of braided polymer material extending between two shackles or between a shackle and a connection point on an earth moving vehicle; the shackle and connecting line forming a safety assembly for retaining a loading tray of an earth moving vehicle in a raised position for maintenance; the method including the steps of:

Forming a length of braided polymer material into an initial loop by splicing ends of the length of braided polymer material together,

Stretching the initial loop so as to bring opposing longer portions of the initial loop to lie side by side,

Enveloping the side by side longer portions within a sheath to leave a secondary loop at each outer end of the sheath,

Inserting a thimble in each secondary loop.

[0074] In a further broad form of the invention, there is provided a method of reducing personnel required from a pair to a single person for securing a tipping tray of a tipping earth moving vehicle in an inclined position for maintenance while complying with applicable health and safety and load regulations; the method including the steps of: replacing one or more steel “D” shackles with a polymer based “D” shackle, replacing one or more steel connecting lines with polymer based connecting lines, fitting the polymer based “D” shackle to a connection point on an underside of the tilting tray when the tray is in the tilted position, attaching a connecting line from the polymer based “D” shackle to an attachment point at a rear transaxle of the vehicle. [0075] Preferably, the weights of the polymer based “D” shackles lies in a range of 4.2-14.2Kg compared to that of equivalent load rated steel “D” shackles having weights in the range of 25-80kg. [0076] Preferably, the equivalent load rating is in a range of 40 to 60tonnes.

[0077] Preferably, the applicable health and safety and load regulations include AS 1333 and IS013333:1994.

[0078] In another broad form of the invention, there is provided a method of preparing a tipping tray of an earth moving vehicle for retention in an inclined position for maintenance with a single operator; the method including the steps of: the operator threads a loop at a first end of a connection line onto an opened polymer based light weight “D” shackle,

- the operator lifts the polymer based “D” shackle above head height to align a first thimble of the polymer based “D” shackle with an aperture of a connection point on the underside of the tipping tray, a pin of the polymer based “D” shackle is passed through the first thimble and through the aperture of the connection point, the second thimble is slid onto the pin and secured by a locking element at a threaded end of the pin.

[0079] Preferably, the method includes the further steps of: securing a loop at a second end of the connection line to an attachment point or another polymer based light weight “D” shackle at a rear transaxle of the earth moving vehicle. [0080] Preferably, weight of the polymer based light weight “D” shackle is approximately one sixth of the weight of equivalently work and safety and load regulated steel “D” shackles.

BRIEF DESCRIPTION OF DRAWINGS

[0081] Embodiments of the present invention will now be described with reference to the accompanying drawings wherein:

[0082] Figure 1 is a partial view of a rear end of a earth moving truck with the safety assembly of the invention in position;

[0083] Figure 2 is a perspective view of shackle component of the safety assembly of figure 1;

[0084] Figure 3 to 5 illustrate a sequence of production of a flexible portion of the shackle and of the connecting line of the safety assembly of figure 1. DESCRIPTION OF EMBODIMENTS

[0085] With reference to figure 1, a safety assembly 10 according to the invention, comprises at least one shackle 12 and a connecting line 14. In use the shackle 12 is coupled to a loop 16 at one end of the connecting line 14 and the shackle installed to a connection point 18 at the underside of the raised tray 20 of an earth moving vehicle 22, rearward of the transverse tilt axis 24 of the tray 20. In a preferred arrangement, a second shackle 12 is connected to a loop 26 at the other end of the connecting line 14 and the second shackle then connected to a connection point 28, typically positioned on the rear transaxle 29 of the vehicle 22. In an alternative arrangement, depending on the structure of the available connection point 28, the loop 26 may be coupled directly to it. The combined length of the shackles or shackle and connecting line when taut, is such as to secure the tray 20 at the limit of its tilt and prevent it lowering unexpectedly.

[0086] The shackle 12 according to the invention, is a fraction of the weight of an equivalent steel “D” shackle by virtue of its construction. For example, a steel “D” shackle required to secure the 50tonne tray of a 300tonne earth moving vehicle may weigh 15kg whereas the weight of an equivalent capacity shackle of the invention weighs just 2.9kg. Some earth moving trucks are even larger than this ranging up to 700tonne when loaded, with the equipment to secure a tray of such a vehicle tipped in a raised position accordingly required to be much heavier. In some vehicles two sets of shackle and connecting line may be used.

[0087] For example, for an ultra class truck which may have a load tray weighing 50tonnes, the load capacity of the safety device, usually a pair of safety devices, is rated on the force required to hold the tray with its centre of gravity over the tipping axis of the tray. Although when in this position a shackle of lOtonne capacity would suffice, in practice a safety margin is added to the shackle load rating to bring the load capacity to 50 tonnes. Preferably, to cover a range of smaller trucks to the largest, load ratings for the shackle and connecting line of the invention may range from 20 to lOOtonnes.

[0088] Turning now to figure 2, the shackle 12 of the invention is comprised of an assembly of braided polymer material 30 and a transverse pin 32. The assembly of polymer material 30 is formed by splicing together opposite ends of an initial length of braided bundles or one single loop of polymer strands together to form an initial loop 32 as shown in figures 3 and 4.

[0089] This initial loop 32 is then stretched and the opposing longer portions of the loop drawn together and secured to lie side by side within an enveloping sheath 34 as shown in figure 5, to leave two secondary loops 36 and 38, one at each opposite outer end of the assembly 30.

[0090] For the shackle 12, a shorter version of the assembly shown in figure 5 is now prepared by inserting a first thimble 40 into a first loop 36 secured by seizing or lashing 42 around regions of the braided polymer material extending from the first thimble 40. A second thimble 44 is similarly secured in the second loop 38, again by lashing 46.

[0091] The transverse pin 32 of the shackle 12, as shown in figure 2, comprises a shaft 48 with a larger diameter head 50 at one end and a projecting threaded section 52 of smaller diameter at the opposite end. The first thimble 40 is a free sliding fit on the shaft 48 and in use, locates on the shaft adjacent to the head 50. In an alternative arrangement, the first thimble 40 may be an integral part of the shaft 48.

[0092] The second thimble 44 is necessarily a sliding fit on the shaft 48 but its position is limited by an inwardly projecting rim leaving an aperture just larger than that of the threaded section 52, so that in use, the projecting rim of the second thimble 44 locates against the shoulder of the shaft at the root of the threaded section. In use, the second thimble 44 is secured in position by a threaded locking element 56 driven onto the threaded section 52.

[0093] The connecting line 14 is of similar construction to that of the assembly of polymer material 30 of the shackle 12, but of greater length. As with the loops at the outer ends of the assembly of polymer material of the shackle, the loops 16 and 26 of the connection line 14 may also be fitted with thimbles, sized to allow coupling with the shackle 12 at one end and with the connection point 28 on the vehicle transaxle at the other. The connection of the connection line at the transaxle may be direct but also could incorporate a second shackle, depending on the design of the connection point provided. Alternatively, since the connection point is usually within reach, a standard steel “D” shackle may be used.

[0094] In maintenance departments around Australia, personnel are required in pairs to fit a SUD weighing 25-80kg to RD trays for maintenance to be undertaken. One to raise the shackle and sling and another to attach the pin and nut. It is cumbersome and time-consuming, the strength and dexterity required to fit the equipment preclude some people from the task, and it has caused many workplace injuries.

[0095] The SUD assembly of the present invention by substituting polymer technology to both the shackle and sling from the conventional 25-80kg for those in steel, drastically reduce the weight to a mere 4.2-14.2kg whilst still adhering to same relevant standards AS1333 and IS013333:1994 specifying performance and test requirements for mechanical support devices for dump truck trays. As well as the accompanying benefit of a reduction in personnel required, the enormous weight reduction allows a wider range of personnel to perform this aspect of the maintenance task.

[0096] Consequently, increasing safety and enabling inclusion, simultaneously increasing production by reducing machine downtime. Because of their weight and the laborious manner in which steel shackles and slings must be fitted, steel shackles are often left assembled to the trays of these trucks which requires a considerable waste of resources in operations with many trucks and can be damaged when the truck is going about its normal duties. By contrast, the polymer shackle and sling of the present invention, are so easily fitted into position by one person that a set can be used many times over for the entire fleet of trucks, therefore limiting the chance of a damaged set been used due to the SUD been left insitu during normal use, therefore placing maintenance workers at risk when working under the tray.

In Use

[0097] In use, for maintenance of a large tipping earth moving vehicle which requires access to the area under the tray of the vehicle, the tray is raised to its fully tilted position, either by means of its hydraulic rams or by other means and secured in the tilted position by means of the “safety up device” or safety device 10 of the invention. While the tray is in its tipping position, an operator takes a polymer based, light weight shackle 12 according to the present invention, opens the shackle by undoing the locking element 56 from the threaded end of the pin 32 of the shackle and removing the second thimble 38. A loop of the connecting line 30 is then threaded onto the braided assembly of polymer material of the shackle. The operator then lifts the shackle to approximately shoulder height, sometimes with the help of a step ladder, and brings the first thimble into alignment with an aperture of a connection point on the underside of the tray.

[0098] The threaded end of the pin of the shackle is then inserted through the aperture of the connection point on the underside of the vehicle tray, the second thimble slid onto the pin and secured by the threaded locking element. The other loop of the connecting line connected to a connection point located on the transaxle of the vehicle, or to a second shackle at the transaxle.