AU2008237592B2 - Improvements in Articulated Vehicles - Google Patents

Abstract

A trailer for use in an articulated vehicle. The trailer comprises first and second parts movable longitudinally relative to each other whereby to place the trailer into load transporting and load handling positions. The first 5 part has hook lift means secured thereto, and the second part comprises road wheels and a fifth wheel assembly adapted for articulating connection of a further trailer behind said trailer. In the load handling configuration the fifth wheel assembly lies below said hook lift means so that the hook lift means can lift a load from a ground surface onto said first part while clearing the fifth 10 wheel assembly. In the load transporting configuration the fifth wheel assembly lies below and behind said hook lift means and the load so that the further trailer can be secured to said fifth wheel assembly for normal articulation thereon. too 4c)

Description

1 5 IMPROVEMENTS IN ARTICULATED VEHICLES 10 FIELD OF THE INVENTION This invention relates to improvements in articulated vehicles and more particularly to an articulated vehicle having a trailer that is equipped for self 15 loading of objects onto the trailer and that is provided at a rear end with a fifth wheel assembly. BACKGROUND The present invention is directed to articulated vehicles having at least one trailer adapted to carry modular loads, such as large skips of the types 20 used for collection of scrap metals, industrial wastes and the like. Such loads are sometimes required to be picked up or left where there are no facilities available to lift them onto and off the trailers, so that vehicles with self-loading (and unloading) capabilities are desirable. Various lifting devices have been developed for providing trucks and trailers with self-loading capabilities for 25 such containers, and although most often seen in non-articulated vehicles, self-loading devices have also been developed for articulated vehicles. The invention addresses specific shortcomings in known arrangements for provision of self-loading and self-unloading capabilities in articulated vehicles, that has. 30 Articulated vehicles enable the carrying on ordinary roads of loads that are larger than can be carried on such roads by non-articulated vehicles. Thus, particularly where loads are of comparatively low value for a given volume (as in the case of industrial wastes, scrap and the like) the use of articulated vehicles can be important as a way to reduce haulage costs. 35 Several types of articulated vehicles are known. A common one is the so-called semi-trailer, comprising a tractor vehicle and a single trailer 2 connected thereto by a so-called "fifth wheel", which enables the trailer to articulate relative to the tractor about an upright axis as required. Another type of articulated vehicle, of which an example 20 is shown in Figure 1, comprises a tractor vehicle 1 articulatingly connected to a first trailer 5 2 by a fifth wheel 3 (as in a semi-trailer) and a second trailer 4 behind and articulatingly connected to the first trailer 2, by a fifth wheel 5 fitted adjacent to a rear end of the first trailer 2. Such a vehicle is known (at least in Australia) as a "B-Double". Having two trailers instead of the single trailer of a semi trailer, a B-Double vehicle can reduce haulage costs. 10 Vehicle 20 is shown as loaded with three large waste material containers (skips), namely container 22 on lead trailer 2, and two containers 24 and 26 on second trailer 4.These are of about the size and shape of ISO standard shipping containers (i.e. box-like, with nominal dimensions of 8-feet (width) by 8 feet (height) by 20 feet (length). 15 Still another type of articulated vehicle is a "road train", comprising a tractor and three (or even more) trailers. A vehicle 6 of this type, having three trailers, is shown in Figure 2. Vehicle 6 comprises in effect a B-Double vehicle 7 with a third trailer 8 articulatingly connected to and behind the rearmost trailer 10 of the B-Double 7. The third trailer 8 is not directly coupled to trailer 20 10, but is articulatingly connected at its leading end to a wheeled "dolly" 12 by a fifth wheel 13 on the dolly12, the dolly 12 in turn having a towbar 9 secured thereto that is secured to trailer 10 by a pintle-type connection 11. In another type of three-trailer road train, not shown, the second trailer has a fifth wheel at its rear end, like the leading trailer, and the third 25 (rearmost) trailer simply connects articulatingly to the fifth wheel of the second trailer, there being no "dolly". Such a road train has only three points of articulation (i.e. at the three fifth wheel assemblies) whereas the road train 6 has four points of articulation (i.e. at the three fifth wheel assemblies and at the pintle connection). 30 The use of B-Double and road train-type articulated vehicles with waste skips of the type described is desirable as a way to enable the hauling of multiple skips and so to contain costs, but provision of self-loading capabilities for such a vehicle presents a problem. Side loading devices for trailers are known but are expensive, and one would be required for each trailer.

3 Self-loading devices which can lift containers over the end of a vehicle have been developed, but it is believed that no satisfactory self-loading arrangement has been provided that enables the loading and unloading of containers over an end of an articulated vehicle trailer where that end has a 5 fifth wheel fitted as in B-Doubles and road trains as described above. The present invention provides such a device. It is desirable that an articulated vehicle need only one self-loading device, and that all trailers of the vehicle be able to be loaded and unloaded using that device. This too can be achieved in accordance wih the present 10 invention. Although applicant's interest is in the transport of waste and scrap skips for the reasons given above, the present invention is believed to be potentially applicable to the carrying of other containers and modular loads on articulated vehicles, and there is no intention to restrict its scope to skips only. 15 SUMMARY OF THE INVENTION In one aspect the invention provides a trailer for use in an articulated vehicle wherein: said trailer comprises first and second parts movable longitudinally relative to each other whereby to place said trailer into load transporting and 20 load handling positions; said first part has hook lift means secured thereto; said second part comprises road wheels and a fifth wheel assembly adapted for articulating connection of a further trailer behind said trailer; in said load handling configuration said fifth wheel assembly lies below 25 said hook lift means so that said hook lift means can lift a load from a ground surface onto said first part while clearing said fifth wheel assembly; in said load transporting configuration said fifth wheel assembly lies below and behind said hook lift means and said load so that said further trailer can be secured to said fifth wheel assembly for articulation thereon. 30 In a first embodiment, (a) said second part comprises an elongate frame articulatingly securable to a fifth wheel assembly of a vehicle by which said trailer is to be towed; and 4 (b) said first part comprises a cradle to which said hook lift means is secured and which is supported by and movable longitudinally on said second part between firstly a rear position in which a portion of said cradle extends over said fifth wheel assembly so 5 that said hook lift means can lift said load onto said cradle said load clearing said fifth wheel assembly while being thus lifted, and secondly a forward position wherein said cradle said hook lift means and said load are carried by said second part forward of said fifth wheel assembly. 10 Preferably in this embodiment, said hook lift means is adapted when said cradle is in said rear position to place at least a rear end of said load remote from said hook lift means onto a second trailer positioned behind and approximately in longitudinal alignment with the said trailer. More preferably, 15 (a) when said cradle is in said rear position the portion of said cradle extending over said fifth wheel assembly is supported from below by at least one support means in a working position thereof; and (b) said support means is movable from its working position to a stowed position when said cradle is in said forward position whereby to permit 20 coupling of said further trailer to said fifth wheel assembly and articulation of said further trailer relative to said trailer. Said cradle may be supported and guided for longitudinal movement on said second part by guide means comprised in said second part and positioned forward of said support means. 25 Said guide means may comprise elongate guide rails extending longitudinally on said second part. Although not essential, preferably said support means comprises a roller on which said cradle can roll when moving between the rear position and forward positions thereof. 30 Said support means may be movable pivotally between said working and stowed positions thereof. Pivoting of said support means may be about a generally horizontal and fore-and-aft axis.

5 In one arrangement, the trailer comprises a plurality of said support means and: (a) said plurality comprises two groups of support means; (b) said groups are located on opposite sides of a longitudinal centerline of 5 said trailer; and (c) each group comprises at least two support means longitudinally spaced apart when in their working positions. Preferably in this arrangement, each said group of support means when in working position is positioned to support one of a pair of elongate 10 members comprised in said cradle. In a second embodiment, (a) said first part comprises an elongate frame articulatingly securable to a fifth wheel assembly of a vehicle by which said trailer is to be towed; (b) said hook lift means is arranged to lift a load over a rear end of said 15 first part in the load handling configuration; and (c) said second part comprises a subframe slideably secured to a rear portion of said elongate frame for movement between a forward position corresponding to the load handling configuration and a rearward position corresponding to the transporting configuration. 20 Preferably, for both the first and second embodiments, said hook means lift comprises: an assemblage of parts that during lifting of said load onto said trailer in combination assume approximately the shape of an "L" having first and second arms defining the "L", a free end of said first arm pivoting about a 25 transverse pivot axis held fixed relative to said first part and a free end of said second arm bearing grasping means that grasps said load; and actuating means arranged for rotating said assemblage about said transverse pivot axis during lifting of said load onto said trailer. The invention further provides a trailer for use in an articulated vehicle 30 said trailer comprising: a fifth wheel assembly mounted adjacent to a rear end of said trailer and adapted for coupling of a second trailer to the said trailer for articulation about an upright axis; and 6 hook lift means adapted for lifting a load onto said trailer over said rear end of said trailer and said fifth wheel assembly said load remaining clear of said fifth wheel assembly during lifting onto said trailer. The invention still further provides an articulated vehicle comprising: 5 prime mover means adapted for towing trailers; and a leading trailer according to any of the embodiments disclosed herein, articulatingly connected to said prime mover means. The articulated vehicle may additionally comprise a further trailer articulatingly connected to the fifth wheel assembly of the leading trailer. 10 The invention yet further provides a road train type articulated vehicle comprising: prime mover means adapted for towing trailers; and a plurality of trailers articulatingly connected to each other and of which a leading one is articulatingly connected to said prime mover means, 15 and wherein at least one of the trailers accords with an embodiment of the invention as disclosed herein. Preferably in such a road train type articulated vehicle, the trailer connected to the prime mover means accords with embodiment of the invention as disclosed.herein. 20 A connection between two of the trailers of the road train type articulated vehicle may be by means of a pintle on one thereof and a towbar on the other thereof. The invention n further provides a method for transport of waste materials to a central facility from a plurality of sites remote from the central 25 facility comprising the steps of: providing an articulated vehicle that is an embodiment of the present invention as disclosed herein; loading said vehicle with empty waste containers; driving said vehicle to each one of a plurality of remote sites in a 30 sequence; at each said remote site and using the hook lift means unloading at least one of the empty waste containers and/or loading at least one waste container containing waste onto a trailer of said vehicle; and driving said vehicle from a last one of the sequence of remote sites to the central facility. In application of the method, the vehicle may include two or more trailers. 5 Further preferred features and embodiments are disclosed in the subsequent detailed description and claims. Note that throughout this specification, the word "comprise" and words derived therefrom such as "comprising" and "comprised", when used in relation to a set of integers elements or steps are to be taken as indicating 10 that the integers elements or steps are present but not to be taken as precluding the possible presence of other elements integers or steps. Mention of any known prior art (including patent publications) in this specification is explicitly not intended as admitting or conceding that the prior art is common general knowledge well known to any class or group of 15 persons in Australia or elsewhere. BRIEF DESCRIPTION OF THE DIAGRAMS Figure 1 is a side elevation of a "B-Double" articulated vehicle of known type, to which the present invention is applicable; Figure 2 is a side elevation of a road-train type of articulated vehicle of 20 known type, to which the present invention is applicable; Figure 3 is a schematic side view of an articulated vehicle comprising a tractor and a trailer according to the invention, together with a container positioned ready for loading on to the trailer; Figure 4 is a schematic side view of the vehicle and container shown in 25 Figure 3, the container being shown in a first position assumed partway through the process of being lifted onto the trailer; Figure 5 is a schematic side view of the vehicle and container shown in Figure 4, the container being shown in a second position assumed after the first position during loading of the container onto the trailer; 30 Figure 6 is a schematic side view of the vehicle and container shown in Figure 5, the container being shown in a third position assumed after the second position during loading of the container onto the trailer; 8 Figure 7 is a schematic side view of the vehicle and container shown in Figure 6, the container being shown in a final position where it is loaded onto the trailer; Figure 8 is a schematic side view of the vehicle and container shown in 5 Figure 3, with the container shown in the process of being dumped (i.e. emptied) while being held on the trailer; Figure 9 is a schematic side view of a portion of the trailer shown in Figure 3, now in the process of loading the container onto another trailer; Figure 10 is a side view of portion of the trailer and of the container 10 shown in Figure 8, substantially in the configuration shown in Figure 8; Figure 11 is a side view of portion of the trailer and of the container shown in Figure 4, substantially in the configuration shown in Figure 4; Figure 12 is a cross-sectional view of the trailer of the vehicle shown in Figure 6, the section being taken at station "12-12" and excluding detail 15 beyond station "A-A" Figure 13 is a cross-sectional view of the trailer of the vehicle shown in Figure 10, the section being taken at station "13-13" and excluding detail beyond station "B-B"; Figure 14 is a side elevation of a trailer according to a further 20 embodiment of the invention, partway through the process of lifting a load; Figure 15 is a side elevation of the trailer shown in Figure 14 configured for transport of a load and for connection to the trailer of a further trailer; Figure 16 is a perspective view of a rear part of the trailer shown in 25 Figures 10 - 13, with a movable cradle of the trailer omitted; Figure 17 is a schematic longitudinal section of a trailer that is a further alternative embodiment of the invention. In Figures 1 - 17 inclusive, various mechanical features have been omitted for clarity. 30 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The invention provides in a first aspect a trailer for an articulated vehicle, the trailer being able to self-load, from a ground surface, a container or other modular load using a so-called "hook lift" mechanism, the modular load being lifted over a fifth wheel mounted adjacent to an end of the trailer.

9 The trailer also has a self-unloading capability whereby the modular load can be returned to the ground. In a preferred embodiment of the invention, the modular load can also be transferred from the trailer to another trailer without the use of additional equipment. 5 These capabilities will be described firstly by reference to a vehicle of the B-Double type, similar to the conventional B-Double vehicle 20 shown in Figure 1. The loads to be handled will be assumed to be waste skips the same as skips 22, 24 and 26 in Figure 1, but again it is emphasized that other modular loads suitable for handling by a hook lift mechanism can be handled. 10 Figure 3 shows a tractor 40 of conventional type, and a trailer 42 that is the lead trailer of a B-Double vehicle. Trailer 42 is connected to tractor 40 in known manner by means of a "fifth wheel" 44 provided on tractor 40. The fifth wheel 44 is conventional and therefore does not need to be described in detail here. Its purpose is to ensure that trailer 42 can articulate relative to tractor 40 15 about an upright axis 46, and also pitch and roll to a limited extent relative to the tractor 40, as required if a surface on which the tractor 40 and trailer 42 are travelling is not perfectly flat. Trailer 42 has adjacent to its rear end a fifth wheel 48 whereby a second trailer 50 (not shown in Figure 3) can be connected to trailer 42, so as 20 to be able to articulate about an upright axis 52. Trailers 42, 50 and tractor 40 together constitute a B-Double vehicle 54 similar to the conventional B-Double vehicle 20 shown in Figure 1. Also shown in Figure 3 is the front end of a rectangular box-like container 56 of the type mentioned above, on a ground surface 58. Container 25 56 is positioned directly behind trailer 42 and with its length in alignment with the length of trailer 42, as is required to start the process of loading of container 56 onto trailer 42. Trailer 42 is able to lift container 56 onto itself, over its rear end, using a hook-lift mechanism 60 of known type, despite the presence of fifth wheel 48. Figure 3 is schematic, with much mechanical detail 30 omitted, and the hook lift mechanism 60 is therefore represented only by showing its three main links 62, 64 and 66. Figures 4 - 9 inclusive, also schematic and omitting much mechanical detail, will show how these links move when hook lift mechanism 60 is operated. Further detail on hook lift mechanism 60 will also be provided by reference to Figures 10 and 11.

10 Hook lift mechanism 60 is mounted on a cradle 68 that is movable longitudinally on trailer 42. Cradle 68 is slidingly received in rails 94 that extend longitudinally on trailer 42. For lifting container 56 onto trailer 42, cradle 68 is placed in its rearmost possible position, as shown in Figure 3. In 5 that rearmost position, a rear portion of cradle 68, extending beyond rails 94, is supported above fifth wheel 48 by rollers 86 that are in turn supported on brackets 88 mounted to trailer 42. Container 56 has a fitting 70 located transversely centrally on its front wall 72 and adapted to provide a lifting point for a hook 74 at a free end of link 10 62. (Hook 74 when in use is adequately represented as a simple point of pivoting between link 62 and container 56 for the purposes of Figure 3 - 9.) Links 62 and 64 are pivotally connected to each other at pivot 76 which allows them to pivot in the plane of the page of Figure 3. Links 64 and 66 are pivotally connected to each other at pivot 78 which allows them to pivot in the 15 plane of the page of Figure 3. Link 66 is pivotally connected to cradle 68 at pivot 80 and can pivot in the plane of the page of Figure 3. Referring to Figure 4, the loading process begins by rotation in the sense shown by arrow 186 of links 62 and 64, held fixed relative to each other, about pivot 78 (i.e. without any relative rotation of links 62 and 64 about 20 pivot 76). Link 66 is held stationary relative to cradle 68 at this stage. Hook 74 is thus lifted and moved forward, bringing with it fitting 70 of container 56, until container 56 comes into contact with a transversely extending roller 82 that is mounted to link 66 near pivot 80. Transversely extending rollers 84 are provided at a rear lower edge of 25 container 56, and roll on ground surface 58 during this process. Rotation of links 62 and 64 together about pivot 78 then continues, with rollers 84 leaving ground surface 58 and container 56 being supported by roller 82 and hook 74, until the position shown in Figure 5 is reached, beyond which link 64 cannot go. 30 Next, link 62 rotates in the sense shown by arrow 188, with links 64 and 66 held stationary relative to cradle 68, until the configuration shown in Figure 6 is reached. At this point, container 56 is supported on roller 82 and on supports 90 comprised in cradle 68 and supports 92 comprised in link 66. Note that at this point, container 56 overhangs the rear end of cradle 68.

11 In the next stage of the process of loading container 56, cradle 68 is slid forward along rails 94, carrying with it hook lift 60 and container 56, still in the positions relative to cradle 68 shown in Figure 6, until the configuration shown in Figure 7 is reached. In this configuration, the container 56 is far 5 enough forward on trailer 42 that cradle 68 and container 56 do not lie over fifth wheel 48, and so cannot prevent the securing of trailer 50 to fifth wheel 48 in normal manner. Also, in this configuration, there is no need for any part of cradle 68 to be supported on the rollers 86. Brackets 88 are accordingly folded downwardly in a way described below (and so are not visible in Figure 10 7), whereby they and rollers 86 also present no obstacle to securing of trailer 50 to fifth wheel 48. A front end of trailer 50 is shown in phantom outline in Figure 7, in the position it adopts when coupled to trailer 42 via fifth wheel 48. Thus, following the sequence shown in Figures 3 to 7, a container 56 on ground surface 58 can be loaded onto trailer 42, despite trailer 42 being of 15 the type with a fifth wheel 48 adjacent to its rear end. Hook lift 60 also permits container 56, once loaded onto trailer 42, to be dumped, i.e. emptied of its contents. This is important for the application where container 56 is a scrap or waste container. Referring to Figure 8, with cradle 68 in its forward position (i.e. as in Figure 7) brackets 88 are raised 20 again, so that rollers 86 are once again positioned to support a rear part of cradle 68 to the extent required. Cradle 68 is moved backward along rails 94 until its rearmost position is again reached. Then, hook lift 60 is operated as follows to dump the container 56. Links 62, 64, and 66 are prevented from rotation relative to each other (i.e. about pivots 76 and 78) and are rotated as 25 a unit about pivot 80 in the sense shown by arrow 190 so as to rotate container 56 to an angle such as that shown in Figure 8, sufficiently high for the contents of container 56 to leave it, provided the rear doors (not shown) of container 56 are opened. During this process, container 56 is supported by hook 74, and supports 92 (which are transversely spaced apart) and/or roller 30 82. After completion of dumping, the combination of container 56, and links 62, 64 and 66 can be rotated downward so that container 56 resumes a horizontal position and if desired moved forward to the "transporting" position shown in Figure 7.

12 Container 56 may be unloaded onto ground surface 58 from trailer 42 using hook lift 60, by essentially reversing the process that has been described by reference to Figures 3 to 7. In addition, hook lift 60 can be used to transfer container 56 onto trailer 50, In Figure 9, trailer 50 is shown 5 positioned directly behind and in alignment with trailer 42, with such a transfer in progress. With trailer 50 in such a position, cradle 68 can be moved backwards until container 56 overhangs the front to trailer 50. Then, when links 62 and 64 are prevented from rotating relative to each other and rotated as a unit about pivot 78 in the sense shown by arrow 191, container 56 can be 10 transferred to trailer 50. The rollers 84 on container 56 roll on an upper surface 96 of trailer 50. Trailer 50 is preferably provided with guiding means to ensure that container 56 remains centrally positioned on trailer 50 as it is positioned and moved thereon. For example, trailer 50 may have side rails 98 raised above surface 96, suitably robust and extending lengthwise on 15 opposite sides of surface 96. Trailer 50 is provided with suitable means (not shown) for securing container 56 in its final position. In Figure 9, trailer 50 is shown as disconnected from trailer 42. Containers such as container 56 can be transferred to trailer 50 over either end provided each one overhangs the end of trailer 50 before the hook lift 60 20 begins to transfer it in the way shown in Figure 9. Reflecting this fact, a second container 98 is shown loaded on trailer 50 with its lift fitting 100 (corresponding to fitting 70 of container 56) facing the rear end of trailer 50, as it would do following transfer from trailer 42 over the rear end of trailer 42 by hook lift 60. 25 Container 56, if loaded onto trailer 42, can also be transferred to trailer 50 over the front end thereof if trailer 50 is coupled to trailer 42 at fifth wheel 48, in just the same way as shown in Figure 9, save that cradle 68 is not (and cannot be) moved to its rearmost position. All that is required is to ensure that container 56 overhangs the front end of trailer 50. However, if three 30 containers such as container 56, positioned on a ground surface, are to be loaded and transported, the approach would be as follows: * With trailer 50 disconnected from trailer 42, load a first container onto trailer 42, in the way shown in Figures 3 - 7; 13 * Position trailer 42 in line with trailer 50 and transfer the first container onto one end of trailer 50; e Load a second container onto trailer 42; - Position trailer 42 in line with trailer 50 for transferring of the second 5 container onto the other end of trailer 50 and carry out that transfer; * Load the third container onto trailer 42, positioning the third container in the "transporting" position shown in Figure 7; * Couple trailer 50 to trailer 42 via fifth wheel 48. This procedure can be readily extended to the case of loading 10 containers (or other items suitable for the use of a hook lift) onto road train type vehicles, including the type shown in Figure 2. Figures 10 and 11 are side views of a rear portion of trailer 42, and show hook lift mechanism 60 in more detail than Figures 3 - 9. (However, Figures 10 and 11 also omit some inessential detail in the interests of clarity.) 15 For the container-dumping operation shown in Figures 10 and 8, links 64 and 66 are locked together so as to constitute a single member pivotable about transverse-axis pivot 80. Hydraulic actuators 106, one on either side of links 64 and 66, are pivotally anchored to cradle 68 at 108 and to link 64 at 110, and can be extended to raise container 56 to the dumping position 20 (Figures 8, 10) and retracted to lower it to a horizontal position (Figures 6, 7). Another hydraulic actuator 112 (see Figure 11) is pivotally anchored to link 64 at 114 and to link 62 at 116, and can be kept at constant length during the dumping process, so that link 62 also remains stationary relative to links 64 and 66. 25 For the loading operation shown in Figure 11 and Figures 3 - 7, link 66 is held stationary relative to cradle 68 and link 64 is made to pivot about transverse-axis pivot 78 by retraction of the hydraulic actuator 106 with actuator 112 held at constant length so that link 62 does not rotate about pivot 76. Then the rotation of link 62 about transverse-axis pivot 76 between the 30 positions shown in Figures 5 and 6 is achieved by retraction of actuator 112. Hook lift mechanism 60 is of a general type known in the art, in which the load to be handled is supported on an L-shaped rotatable member (identifiable in mechanism 60 as the combination of links 62 and 64 when 14 loading/unloading and the combination of links 62,64 and 66 when dumping). For example, an essentially similar hook lift device is shown and described in English in the published specification of US Patent 5102284 (Raisio, 1992), which is incorporated herein by reference in its entirety. Assorted variations of 5 the basic mechanism are known, and their applicability to the present invention may be readily assessed by persons skilled in the art. For example US Patent 5102284 (Raisio, 1992) is concerned mainly with improvements to hooks which could be applied to hook 74. For further example, applicant's prototype is of a type in which link 64 actually comprises two parts 102 and 10 104 of which one (102) telescopes within the other (104). Such a variation may be used in addition to or as an alternative to the rotation of link 62 about pivot 76. Although the general type of hook lift exemplified by hook lift mechanism 60 is preferred by applicant for use in the invention, other types of 15 mechanisms for lifting containers or the like onto a vehicle over an end of the vehicle have been developed and may be substituted for it where suitable for use with a movable cradle generally like cradle 68. For example, the chain driven lifting device described in the published specification of US Patent 4889464 (Self, 1989), hereby incorporated by reference in its entirety, is 20 believed to be applicable as an alternative to hook lift 60. Figure 12 shows a cross-sectional view of trailer 42, including rails 94, and of cradle 68 with the hook lift 60 and container 56 positioned as shown in Figure 6. Much structural detail has been omitted from Figure 12, and in particular the structure of trailer 42, which is essentially conventional. Rails 94 25 extend lengthwise along trailer 42 and are firmly and fixedly secured thereto. They are of "C" (channel) section and arranged as a handed pair, as shown. Cradle 68 comprises firstly a handed pair of side members 118, of which lower portions are slidingly and locatingly received between, and supported by, rails 94, and secondly cross-members 124 joining side members 188. 30 Supports 90 are provided on side members 118 at longitudinally spaced positions for supporting and laterally locating longitudinal skid members 130 that are comprised in container 56. Item 132 represents a notional vertical plane that is transversely central on trailer 42 (i.e. midway 15 between its wheels) and rails 94, container 56 and supports 90 are symmetrically positioned on opposite sides of plane 132. In the configuration shown, link 64 and actuators 106 are received in a space 120 defined between container 56, side members 118 and members 5 124. The height of rails 94 is such that they are partially let in to a conventional "tray" structure 126 of trailer 42. (However, tray structure 126 is itself not essential to the invention). Item 128 represents the height of a "deck" at the rear end of trailer 42 on which fifth wheel 48 is mounted, and it will be noted that the level of rails 10 94, and therefore of side members 118 of cradle 68 is higher than deck level 128, so that fifth wheel 48 is cleared when cradle 68 is moved to the rear position shown in Figures 10 and 11. Figure 13 is a cross-sectional view of trailer 42 and cradle 68, showing how the portion of cradle 68 that protrudes rearwardly of rails 94 when cradle 15 68 is moved rearwardly on trailer 42 is supported on rollers 86. See also Figure 16, in which various mechanical details are omitted. Structural detail of trailer 42 is omitted from Figure 13 for clarity. Each roller 86 is supported on a bracket 88 so that as cradle 68 is moved over its longitudinal position, one of the side members 118 of cradle 68 passes over and is supported by, that 20 roller 86. In applicant's prototype of trailer 42, three longitudinally spaced apart rollers 86 were provided .for each side member 118, but this particular number may be varied. Each roller 86 can rotate freely about a horizontal and transversely extending axis 134. Each bracket 88 is mounted to trailer 42 so as to be pivotable about an approximately horizontal axis 136 extending in a 25 longitudinal direction, the axes 136 being located slightly above the height of the "deck" 128. For each of the brackets 88 shown in Figure 13, a hydraulic actuator 138, anchored at one end 142 to the trailer 42 and at the other end 144 to a radius arm 146 connected to the bracket 58 is provided to rotate the bracket 88 between an upright position in which its roller 86 is positioned to 30 help support cradle 68, and a lowered position in which the bracket 88 lies below the height of upper surface 140 of the fifth wheel 48. In Figure 13, the bracket 88 at the left is shown in solid lines in the upright or working position and in chain dotted lines in the lowered position. When all brackets 88 are in their lowered positions, and cradle 68 is positioned sufficiently far enough 16 forward on trailer 42, there is no obstacle to the trailer 50 being coupled to trailer 42 at fifth wheel 48. When all brackets 88 are in their upright positions, cradle 68 can be moved to its rearmost position for dumping, loading, unloading and transferring of containers 56, and be adequately supported 5 against downward deflection, although of course trailer 50 cannot then be connected to trailer 42. Each bracket 88 may have its own actuator 138 as shown or, alternatively several brackets may be connected together (not shown) so as to be operable by one actuator only. 10 Each bracket 88 has a shoulder 148 arranged to abut "deck" 128 at a sufficiently stout point thereof, firstly to act as a stop that prevents the bracket 88 from rotating beyond its correct upright position when actuator 138 is extended, and secondly to provide a direct path for loads applied to roller 86 by cradle 68 to the trailer 42 structure. 15 It will be apparent to the skilled person that other possible arrangements could be used to raise and lower support rollers such as rollers 86. As one example only, although brackets 88 are shown as pivotable about longitudinally extending axes 136 in Figures 13 and 16, roller-supporting brackets (not shown) could be provided as alternatives to brackets 88 that 20 pivot about transverse axes instead of longitudinal axes. Certain details of the operating mechanism of trailer 42, cradle 68 and hook lift 60 have been omitted for clarity and are appropriate to mention here. First, the movement backward and forward of cradle 68 may be effected by any suitable means, for example a hydraulic linear actuator (piston-in 25 cylinder), telescopic or otherwise, a rack and pinion drive, or a chain drive using roller chain or link-type chain. In the applicant's prototype, a chain drive using a hydraulic motor and link-type chain (not shown) was used, runs of chain being accommodated in the space 122 (Figure 12). The type of drive is not of the essence of the invention. 30 Second, it is desirable to provide suitable positive locking means to ensure that there is no unintended longitudinal movement of cradle 68 relative to trailer 42, for example when the container 56 is in the fully forward transporting position shown in Figure 7 or when the cradle 68 is the fully rearward position for dumping and loading and unloading. In the applicant's 17 prototype, hydraulic actuators (not shown) were secured on trailer 42 and arranged to move pins (not shown) transversely into and out of engagement with side members 118 of cradle 68, to lock cradle 68 against longitudinal movement. 5 The particular sequence of operations shown in Figures 3 - 7 and described by reference to those Figures may be varied somewhat, provided the basic operations of loading, unloading and, where relevant, transferring of loads are still achievable. For example, the rotation of link 62 between its position as shown in Figure 5 and its position as shown in Figure 6 may be 10 executed simultaneously with at least a part of the rotation of link 64 in shown in the Figures as occurring between the configurations shown in Figures 4 and 5. There will now be described a trailer 200 that is a further and alternative embodiment of the invention. This is shown in schematic views 15 (omitting much mechanical detail) in Figures 14 and15. Instead of placing a hook lift on a cradle that is movable over a fifth wheel assembly, as described by reference above, trailer 200 has a hook lift mechanism 202 secured thereon in a fixed position. Hook lift mechanism 202 is shown schematically in the way mechanism 60 is shown schematically in 20 Figures 3 - 8 and operates on the same basic principle. It can lift a container type load 204 over a transverse-axis roller 206 onto trailer 200. Figure 14 shows this process at the same stage of operation as is shown in Figure 4 for hook lift mechanism 60, i.e. with load 204 partly loaded onto trailer 200 and in contact with roller 206. Figure 15 shows load 204 fully loaded on to trailer 200. 25 Trailer 200 and hook lift mechanism 202 would be provided with suitable supports (for clarity not shown, but corresponding in function to items 90 and 92 described earlier) for support of load 204 in the transporting position shown in Figure 15. A link 210 of hook lift mechanism 202, corresponding to link 64of hook lift mechanism 60, is telescopically variable in length between pivots 220 30 and 222, so that load 204 can be moved forward from the position shown in chain-dotted lines in Figure 15 to its position for transport, shown in solid lines in Figure 15. Trailer 200 has a rear-end fifth wheel assembly 212 (corresponding to fifth wheel assembly 48 of trailer 42), secured on a rear section 208 of trailer 18 200 that is longitudinally slideable in a main portion 216 of trailer 200. Also secured to rear section 208 are road wheels 214 of trailer 200. In Figure 15, rear section 208 is shown in the transporting position in which it is placed when the trailer 200 is to be towed. With load 204 on board and fully forward 5 (solid lines in Figure 15) in its transporting position, and with rear section 208 in its transporting position, fifth wheel assembly 212 is so positioned that a further trailer (not shown) can be attached to it, and articulate normally about an upright axis 224. However, when rear section 208 is moved longitudinally forward 10 (relative to trailer 200) to its load-handling position as shown in Figure 14, fifth wheel assembly 212 lies beneath hook lift mechanism 202 so that load 204 can be lifted onto trailer 200, deposited on ground surface 226, dumped (in the same way described above for hook lift mechanism 60), or transferred to another trailer, while remaining clear of fifth wheel assembly 212. 15 Movement of rear section 208 relative to the main portion 216 of trailer 200 may be by a suitable actuator (not shown) such as a hydraulic ram, or alternatively may rely on application of brakes to immobilize wheels 214 and driving the towing vehicle (not shown) of trailer 200 forwardly or backwardly as required, so that main portion 216 slides on rear section 208. In Figure 15, 20 the positions of road wheels 214 when rear section 208 is in the load-handling position are shown in chain dotted lines. Suitable locks (not shown) are provided to lock rear section 208 in its transporting or load handling positions relative to main portion 216. Although not shown in Figures 14 and 15, fifth wheel assembly 212 25 could optionally be mounted indirectly to trailer rear section 208 instead of directly, via a mechanism capable of raising and lowering fifth wheel assembly 212 as required by an operator, between stowed and operating positions. The principle is shown schematically in Figure 17, in which 212a represents the fifth wheel assembly in operating position, in which a trailer (not shown) could 30 be attached for articulation and towing in normal manner. The stowed position represented by 212b, would be lower, and be chosen when the rear section 208 is to slide beneath main portion 216 (as shown in Figure 14). A link 301 (represented by 301a in operating position and 301 b in stowed position) would be mounted to section 208 for pivoting aboiut an axis 302 and raised 19 and lowered by a suitable actuator (not shown). The problem of designing a rear section 208 that can slide under main portion 216, .may be simplified in this way. (Note that the same approach could in fact also be followed in the 5 embodiment shown in Figures 3 to 13, to ease the problem of obtaining adequate clearance beneath cradle 68 for the fifth wheel assembly 48.) As with the embodiment described by reference to Figures 3 to 13, a person skilled in the art would readily appreciate that various other types of hook lift mechanisms known in the art could be used instead of the type 10 shown schematically as hook lift mechanism 202.

Claims (20)

1. A trailer for use in an articulated vehicle wherein: 5 said trailer comprises first and second parts movable longitudinally relative to each other whereby to place said trailer into load transporting and load handling positions; said first part has hook lift means secured thereto; 10 said second part comprises road wheels and a fifth wheel assembly adapted for articulating connection of a further trailer behind said trailer; 15 in said load handling configuration said fifth wheel assembly lies below said hook lift means so that said hook lift means can lift a load from a ground surface onto said first part while clearing said fifth wheel assembly; 20 in said load transporting configuration said fifth wheel assembly lies below and behind said hook lift means and said load so that said further trailer can be secured to said fifth wheel assembly for articulation thereon. 25

2. A trailer according to claim 1 wherein: (a) said second part comprises an elongate frame articulatingly securable to a fifth wheel assembly of a vehicle by which said trailer is to be towed; and 30 (b) said first part comprises a cradle to which said hook lift means is secured and which is supported by and movable longitudinally on said second part between firstly a rear position in which a portion of said cradle extends over said fifth wheel assembly so 35 that said hook lift means can lift said load onto said cradle said 21 load clearing said fifth wheel assembly while being thus lifted, and secondly a forward position wherein said cradle said hook lift means and said load are carried by said second part forward of said fifth wheel assembly. 5

3. A trailer according to claim 2 wherein said hook lift means is adapted when said cradle is in said rear position to place at least a rear end of said load remote from said hook lift means onto a second trailer positioned behind and approximately in longitudinal alignment with the 10 said trailer.

4. A trailer according to claim 2 or 3 wherein: (a) when said cradle is in said rear position the portion of said 15 cradle extending over said fifth wheel assembly is supported from below by at least one support means in a working position thereof; and (b) said support means is movable from its working position to a 20 stowed position when said cradle is in said forward position whereby to permit coupling of said further trailer to said fifth wheel assembly and articulation of said further trailer relative to said trailer. 25

5. A trailer according to claim 4 wherein said cradle is supported and - guided for longitudinal movement on said second part by guide means comprised in said second part and positioned forward of said support means. 30

6. A trailer according to claim 5 wherein said guide means comprises elongate guide rails extending longitudinally on said second part.

7. A trailer according to any one of claims 4 to 6 wherein said support means comprises a roller on which said cradle can roll when moving 35 between the rear position and forward positions thereof. 22

8. A trailer according to any one of claims 4 to 7 wherein said support means is movable pivotally between said working and stowed positions thereof. 5

9. A trailer according to claim 8 wherein pivoting of said support means is about a generally horizontal and fore-and-aft axis.

10. A trailer according to any one of claims 4 to 9 comprising a plurality of said support means and wherein: 10 (a) said plurality comprises two groups of support means; (b) said groups are located on opposite sides of a longitudinal centerline of said trailer; and 15 (c) each group comprises at least two support means longitudinally spaced apart when in their working positions.

11. A trailer according to claim 10 wherein each said group of support 20 means when in working position is positioned to support one of a pair of elongate members comprise in said cradle.

12. A trailer according to claim 1 wherein: 25 (a) said first part comprises an elongate frame articulatingly securable to a fifth wheel assembly of a vehicle by which said trailer is to be towed; and (b) said hook lift means is arranged to lift a load over a rear end of 30 said first part in the load handling configuration; and (c) said second part comprises a subframe slideably secured to a rear portion of said elongate frame for movement between a forward position corresponding to the load handling 35 configuration and a rearward position corresponding to the transporting configuration. 23

13. A trailer according to any one of claims 1 to 12 wherein said hook means lift comprises: an assemblage of parts that during lifting of said load onto said trailer in 5 combination assume approximately the shape of an "L" having first and second arms defining the "L", a free end of said first arm pivoting about a transverse pivot axis held fixed relative to said first part and a free end of said second arm bearing grasping means that grasps said load; and 10 actuating means arranged for rotating said assemblage about said transverse pivot axis during lifting of said load onto said trailer.

14. A trailer for use in an articulated vehicle said trailer comprising: 15 a fifth wheel assembly mounted adjacent to a rear end of said trailer and adapted for coupling of a second trailer to the said trailer for articulation about an upright axis; and 20 hook lift means adapted for lifting a load onto said trailer over said rear end of said trailer and said fifth wheel assembly said load remaining V clear of said fifth wheel assembly during lifting onto said trailer.

15. An articulated vehicle comprising: 25 prime mover means adapted for towing trailers; and a leading trailer according to any one of claims I to 14, articulatingly connected to said prime mover means. 30

16. An articulated vehicle according to claim 15 and additionally comprising a further trailer articulatingly connected to the fifth wheel assembly of the leading trailer. 35

17. A road train type articulated vehicle comprising: prime mover means adapted for towing trailers; and /-4 a plurality of trailers articulatingly connected to each other and of which a leading one is articulatingly connected to said prime mover means. 5 wherein at least one of the trailers accords with any one of claims 1 to 14.

18. A road train type articulated vehicle according to claim 17 wherein the trailer connected to the prime mover means accords with any one of 10 claims 1 to 14.

19. A road train type articulated vehicle according to claim 17 or 18 wherein a connection between two of the trailers is by means of a pintle on one thereof and a towbar on the other thereof. 15

20. A method for transport of waste materials to a central facility from a plurality of sites remote from the central facility comprising the steps of: providing an articulated vehicle according to any one of claims 15 to 20 19; loading said vehicle with empty waste containers; driving said vehicle to each one of a plurality of remote sites in a 25 sequence; at each said remote site and using the hook lift means unloading at least one of the empty waste containers and/or loading at least one waste container containing waste onto a trailer of said vehicle; 30 driving said vehicle from a last one of the sequence of remote sites to the central facility.