AU2008249215A1

AU2008249215A1 - A ramp arrangement for a land vehicle

Info

Publication number: AU2008249215A1
Application number: AU2008249215A
Authority: AU
Inventors: Denis Di Pasquale
Original assignee: TUFF TRAILERS QLD Pty Ltd
Current assignee: TUFF TRAILERS (QLD) Pty Ltd
Priority date: 2008-11-26
Filing date: 2008-11-26
Publication date: 2009-07-09
Also published as: AU2009100674B4; AU2009100674A4

Description

1 A RAMP ARRANGEMENT FOR A LAND VEHICLE FIELD OF THE INVENTION 5 This invention relates to a ramp arrangement for a land vehicle. This invention also extends to a vehicle having such a ramp arrangement. This invention relates particularly but not exclusively to a ramp arrangement for a trailer, e.g. a heavy duty trailer. This invention also relates particularly to a 10 heavy duty trailer or semi-trailer including the ramp arrangement. It will therefore be convenient to hereinafter describe this invention with reference to this example application. At the same time however it should be realized that the invention is capable of broader application. For example this invention could equally be applied to a ramp arrangement for a vehicle having its own 15 motive power such as a truck or the like. It does not need to be a trailer that is coupled to a prime mover. BACKGROUND TO THE INVENTION 20 Heavy duty trailers for over the road hauling of heavy loads and the like is a ubiquitous feature of modern industrialized economies. In particular trailers can be used for transporting equipment for moving across the ground such as trucks, cars, tractors, bobcats, forklift trucks, bull dozers and other ground moving equipment, front end loaders, and the like. 25 Such ground engaging vehicles or other heavy equipment as described above, are generally carried or supported on the deck of a heavy trailer. During operation it is necessary to load the vehicles on the trailer and also to unload the vehicles from the trailer. This can conveniently be done by providing a 30 driving ramp arrangement at the tail or rear end of the deck of the trailer. The load vehicle can be driven over the ramp to load it from the ground onto the 2 deck of the trailer and also to unload it from the deck of the trailer onto the ground. In the prior art it has been known to provide two parallel track ramps, one 5 towards each side of the vehicle, e.g. trailer, to form the driving ramp arrangement. One such example is shown in Fig 1 of the drawings. As shown the two parallel track ramps are operatively able to pivot between a downwardly inclined operative position extending rearwards away from the vehicle in which they can be driven on and a vertically upstanding inoperative (stowed) position. 10 When the trailer is in use being towed on a road the ramps are in their inoperative position. When the trailer is stationary and it is desired to offload vehicles the track ramps are pivoted from the inoperative position down into their operative position. The ramp tracks then extend from a deck of the trailer 15 down onto the support surface on which it is parked and load vehicles can be driven off the trailer deck and down onto the support surface. A disadvantage of this driving ramp arrangement with the two track ramps is that the two track ramps project vertically upward when the trailer is driven 20 along a road. This arrangement with the upstanding track ramps has a high drag coefficient and causes high level of drag resistance particularly when the trailer is traveling along the road at speed. Yet further it requires a significant pivoting action of a heavy piece of structure to change the ramp to the operative position. The moment applied to the track ramps when they are being lowered 25 into the operative position would be substantial. In an era where there is a drive to reduce energy consumption and particularly fuel consumption it would clearly be advantageous to devise a more energy efficient way of providing a trailer with a ramp arrangement for the loading of 30 vehicles onto the trailer and the unloading of vehicles from the trailer. It would also be advantageous of an elegant engineering solution could be devised that 3 provided a ramp that was easy and quick to move between the operative and inoperative positions. SUMMARY OF THE INVENTION 5 According to one aspect of the invention there is provided a trailer vehicle that includes: a main load support having a load bearing surface; and a ramp arrangement having a ramp body including at least two parts that 10 collectively define a traverse surface, one ramp part being pivotally mounted on the main load support for displacing the traverse surface of the ramp body pivotally relative to the load bearing surface of the main load support, and the other ramp part being mounted on the one ramp part and being displaceable relative to the one ramp part for increasing or decreasing the traverse surface of 15 the ramp body. The one ramp part may be pivotally mounted about a transverse pivot axis towards a rear end of the main load support so that the ramp platform is pivotally displaceable about the pivot axis between a position in which the 20 traverse surface inclines downwardly away from the load bearing surface and a another position in which the traverse surface extends generally planar with the load bearing surface. The other ramp part may be mounted on the one ramp part and may be 25 displaceable relative to the one ramp part in a direction in which the traverse surfaces of the one part and the other part overlap progressively more for decreasing the effective traverse surface of the ramp body, and an opposite direction in which the traverse surfaces overlap progressively less for increasing the traverse surface of the ramp body. The other ramp part may be capable of 30 sliding or translational displacement in a rearwards direction away from the one ramp part for increasing the traverse surface of the ramp body in a rearwards direction.

4 The main load support may include an elongated load support body having a generally rectangular flat load bearing surface defined longitudinally between a leading end and a trailing end of the load support floor and transversely spaced 5 lateral long sides of the floor. The one ramp part may include a generally rectangular ramp platform body defining a generally flat ramp platform traverse surface between its leading end and trailing end and between transversely spaced lateral sides. Also, the one 10 ramp part may include a hinging arrangement for mounting the ramp platform body about a transverse hinge axis towards the rear end of the elongated load support body, so that the ramp platform body may be hingedly displaceable about the hinge axis between a position in which the ramp platform traverse surface inclines downwardly away rewards from the rear end of the load bearing 15 surface and another position in which the ramp platform traverse surface extends generally horizontally with the load bearing surface. The trailer vehicle may be supported on a vehicle support surface, and the ramp platform body may include a ramp support towards its rear end for supporting 20 the ramp platform body on the vehicle support surface when the ramp platform body is hingedly displaced to the position in which the ramp platform traverse surface inclines downwardly rewards away from the rear end of the load bearing surface. 25 The ramp support may include a transversely extending support wall towards the rear end of the ramp platform body that projects away from the ramp platform body and that defines a platform support surface towards its free end for engaging the vehicle support surface. 30 The ramp platform support may be formed integrally with the ramp platform body. That is it may be formed as a part of the structure of the ramp platform body so that it depends downwards below the ramp platform body.

5 The ramp platform support may be engineered to provide load bearing support for a load to be borne by the ramp arrangement, e.g. when vehicles are loaded/unloaded from the trailer, at a point intermediate the main load support 5 and the free end of the ramp track members, thereby to relieve the moment applied to the rear end of the main load support. The ramp platform support may be a static support that does not need to be moved into an operative position when it is used. That is it is not moved 10 between operative and inoperative positions by a folding action of the like. It depends below the ramp platform body in the transport position and when the ramp platform body is pivoted into the inclined or loading position, the downwardly depending ramp platform support is lowered into contact or engagement with the support surface. 15 The transverse support wall towards the rear end of the ramp platform body may be sized to support the rear end of the ramp platform body in a position in which the rear end of the ramp platform traverse surface is spaced away above from the vehicle support surface when the ramp support surface abuts the 20 vehicle support surface. The ramp support wall may be sized to support the rear end of the ramp platform traverse surface spaced at least 0.4 m above the vehicle support surface when the ramp support surface abuts the vehicle support surface. 25 Further, the hinging arrangement for mounting the ramp platform body toward the rear end of the main load support may be arranged so as to permit it to pivot relative to the main load support through at least 10 degrees between the traveling position and the loading position, e.g. a range of 13 to 17 degrees. 30 The other ramp part may includes two laterally spaced elongated ramp track members defining track traverse surfaces between leading ends and trailing ends and transversely spaced long sides. The ramp track members may be 6 displaceable by translational movement in a direction rearward away from the one ramp part for increasing the effective traverse surface of the ramp body in a rearwards direction. 5 The ramp track members may be received within the ramp platform in a retracted position in which track traverse surfaces overlap substantially completely with the ramp platform traverse surface, and may be operatively able to be displaced by translational movement in a direction rearward away from the ramp platform body for increasing the traverse surface of the ramp. 10 The ramp track members may be sized to project rearwards away from the ramp platform body so that the track traverse surface extends in a generally planar fashion between the rear end of the platform traverse surface and the vehicle support surface when the ramp platform body is in its inclined position. 15 The ramp platform body may include a ramp track support surface over which the ramp track members are displaceable when displaced between the retracted and extended positions. The ramp track support surface may include two parallel transversely spaced sliding surfaces over which the two ramp track 20 members are slidingly displaceable when displaced between the retracted and extended positions. The ramp platform body may include a guiding arrangement for guiding the displacement of the ramp extension members between the retracted and 25 extended positions. The guide arrangement may include transversely spaced guide formations and vertically spaced guide formations defining between them a track traveling path along which the displacement of the ramp extension member are guided between the retracted and extended positions. 30 The guide formations may be sized and shaped to be complementary to the outer sides of the ramp track members for snug sliding fitment of the ramp track members in the guide passages.

7 The other ramp part may include a bridging member extending transversely between the ramp track members for holding the ramp track members together in a fixed spaced relationship to each other. Each ramp track member may 5 include an elongated generally flat substantially box-shaped body having a longitudinally tapered rear end portion defining a transverse taper portion face at a taper angle that enables the taper end portion face to lie flat on the vehicle support surface, in use. 10 The trailer vehicle may include a ramp platform drive means for driving the ramp platform pivotally about the hinge axis. The ramp platform drive means may include a hydraulic drive means, e.g. in the form of two laterally spaced hydraulic actuators, mounted between an undercarriage of the trailer vehicle and the ramp platform body, for displacing the ramp platform pivotally about the 15 hinge axis. Similarly, the trailer may include a ramp track member drive means for displacing the ramp track members towards and away from the ramp platform body between the extended and retracted positions along the ramp track 20 member traveling path. The ramp track member drive means may include a hydraulic actuator mounted between the ramp platform body and the bridging member extending transversely between the ramp track members. The ramp track member drive means may be actuable independently of the 25 ramp platform drive means. The trailer vehicle may also include a locking arrangement for locking the ramp platform body in either one of the positions in which the ramp platform traverse surface inclines downwardly away rewards from the rear end of the load bearing 30 surface or in the other position in which the ramp platform traverse surface extends horizontally generally planar with the load bearing surface.

8 The locking arrangement may include at least two vertically offset transversely open apertures defined by a rear end of the undercarriage of the vehicle and that are associated with the inclined position and the horizontal position of the ramp platform body respectively, and a locking pin transversely retractably 5 displaceable into the apertures at the respective positions for positively locking the ramp platform body relative to the undercarriage of the vehicle in either one of said positions. The trailer vehicle may include at least one user controller unit interfaced with a 10 hydraulic system of the trailer vehicle for controlling the hydraulic actuators and the locking arrangement. Yet also, the undercarriage of the trailer vehicle may includes two transversely space parallel elongated support beams extending longitudinally between a rear 15 end and a front end of the main load support body. The elongated load support body may also include a raised support body portion toward a leading end of the load support body. 20 The trailer vehicle may be a heavy duty trailer and may include a coupling arrangement for coupling to a fifth-wheel hitch of a tractor vehicle. According to another aspect of this invention there is provided a ramp arrangement for a vehicle having a main load support, the ramp arrangement 25 including: a ramp platform that is pivotally mounted about a lateral pivot axis towards a rear end of the main load support, the ramp platform being pivotally displaceable between a loading position in which it inclines downwardly away from the main load support and a travelling position in which it extends 30 generally horizontally; and a ramp extension member having a ramp platform end and a free end mounted on the ramp platform, the ramp extension member being translationally displaceable between a retracted position in which it 9 overlaps with the ramp platform and an extended position in which it projects out of the ramp platform in a rearward direction. The ramp arrangement may include any one or more of the features of the ramp 5 arrangement defined in the first aspect of the invention above. According to yet another aspect of this invention there is provided a road going vehicle including: a main load support; and 10 a ramp arrangement including a ramp platform that is pivotally mounted about a lateral pivot axis towards a rear end of the main load support, the ramp platform being pivotally displaceable between a loading position in which it inclines downwardly away from the main load support and a traveling position in which it extends generally horizontally; and a ramp extension member having a 15 ramp platform end and a free end mounted on the ramp platform, the ramp extension member being translationally displaceable between a retracted position in which it overlaps with the ramp platform and an extended position in which it projects out of the ramp platform in a rearward direction. 20 The load support and the ramp arrangement may include any one or more of the features of the ramp arrangement defined in the first aspect of the invention above. The vehicle may have its own motive means for driving it on a road. 25 The vehicle may be a truck. The truck may have a flat load platform or the truck may have a utility tray. Instead the vehicle may be a utility vehicle with a utility tray. Yet further the 30 vehicle may be a trailer for being towed by a car or a truck. For example the trailer may be a small trailer.

10 The road going vehicle may have an enclosed goods carrying compartment and it is not required to be open to the outside air. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 5 A trailer vehicle and a ramp arrangement in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe an embodiment of the invention in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct 10 persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. In the drawings: 15 Figure 1 is a three dimensional view of a trailer vehicle with a ramp arrangement according to the prior art; Figure 2 is a three dimensional view of a trailer vehicle having a ramp arrangement in accordance with one embodiment of the invention; 20 Figure 3 is a side view of the trailer vehicle in Figure 2 with the ramp in a raised and retracted travel position; Figure 4 is a side view of the trailer vehicle with the ramp in a lowered and 25 extended position; Figure 5 is a top plan view of a ramp platform part forming part of the ramp arrangement; 30 Figure 6 is a side elevational section view along line I-I in Figure 5; 11 Figure 7 is top plan view of another part of the ramp platform showing it attached to chassis support beams of the trailer vehicle; Figure 8 is a side elevational section view along line 11-Il in Figure 7; 5 Figure 9 is a bottom plan view of ramp track members forming part of the ramp arrangement; Figure 10 is a side elevational section view of one of the ramp track members in 10 Figure 9 taken along line III-III; Figure 11 is a side elevational section view of a rear end portion of the trailer vehicle and the ramp arrangement; 15 Figure 12 is a rear end view of the ramp platform; Figure 13 is a side elevational longitudinal section view of a rear part of the trailer vehicle and part of the ramp platform arrangement; 20 Figure 14 is a transverse sectional view of the rear part of the trailer vehicle and part of the ramp platform arrangement in Figure 15 taken along line IV-IV; Figure 15 is a bottom view of the part in Figure 13 showing also a locking arrangement for the ramp platform; 25 Figure 16 is side elevational view of a rear end part of a chassis support beam; Figure 17 is a sectional view of the part in Figure 16 taken along line IIV-IIV; and 30 12 Figure 18 is a side elevational view of a rear end of the trailer and the ramp platform showing controls mounted on a side of the ramp platform. In Figure 1 reference numeral 10 refers generally to a prior art trailer vehicle for 5 a heavy duty truck for over the road hauling of heavy loads. The trailer vehicle 10 includes a loading deck 16 that can be used for transporting equipment such as cars, tractors, bobcats, forklift trucks, bull dozers and other ground moving equipment, front end loaders, and the like. 10 These ground engaging vehicles or pieces of equipment as described above, need to be loaded onto and unloaded from the loading deck 16. Conveniently the trailer vehicle 10 includes a driving ramp arrangement, generally indicated by reference numeral 14, at the tail of the trailer 10 over which the load vehicle can be driven to both load it on the trailer 10 and unload it from the trailer 10. 15 The driving ramp arrangement 14 includes two parallel ramp track members 18, 20, one towards each side of the vehicle 10. As shown the two parallel ramp track members are operatively able to pivot (see arrows 22) between a downwardly inclined operative position extending rearwards away from the 20 vehicle 10 and a vertically upstanding inoperative stowed position. In the stowed position the two ramps tracks 18, 20 stick vertically upward from the trailer 10 when the trailer 10 is driven along a road, so that traverse surfaces of the ramp tracks 18, 20 face the forward traveling direction which creates a 25 high drag coefficient and causes high level of drag resistance particularly when the trailer 10 is traveling along the road at speed. Figure 2 shows a trailer vehicle 22, in accordance with one embodiment of the invention. 30 The trailer vehicle 22 is for a heavy duty truck having a tractor (not shown) for towing the trailer vehicle 22 over a vehicle support surface such as a road. The 13 trailer 22 includes a loading deck, generally indicated by reference numeral 24 that includes a main load support 26 having a load bearing surface 28. The trailer 22 also includes a ramp arrangement 12 having a ramp body 30 including at least two parts 32, 34 defining a traverse surface 36. 5 The one ramp part 32 is pivotally mounted on the main load support 26 for displacing the traverse surface 36 of the ramp body 30 pivotally relative to the load bearing surface 28 of the loading deck 24, and the other ramp part 34 is mounted on the one ramp part 32 and is displaceable relative to the one ramp 10 part 32 for increasing or decreasing the effective traverse surface 36 of the ramp body 30. The loading deck 24 includes an elongated load support body 36 having a generally rectangular flat load bearing surface or floor 28 defined longitudinally 15 between a leading end and a trailing end of the loading deck 24 and transversely spaced lateral long sides of the loading deck 24. The one ramp part 32 includes a generally rectangular ramp platform body 38 defining a generally flat ramp platform traverse surface 36.1 extending between 20 its leading end and trailing end and between transversely spaced lateral sides. The one ramp part 32 also includes a hinging arrangement 40 for mounting the ramp platform body 38 about a transverse hinge axis 42 towards the rear end of the loading deck 24. Thus, the ramp platform body 38 is hingedly displaceable about the hinge axis 42 between a position in which the ramp platform traverse 25 surface 36.1 inclines (see Figures 2 and 4) downwardly in a rearward direction away from the rear end of the loading deck 24 and another position in which the ramp platform traverse surface 36.1 extends generally horizontally (see Figure 3) in plane with the load bearing surface 28 of the loading deck 24. 30 In this embodiment, the hinging arrangement 40 is for mounting the ramp platform body 38 toward the rear end of the loading deck 24 in such a way that it permits the ramp platform body to pivot relative to the loading deck through at 14 least 10 degrees between the inclined position and the horizontal traveling position. Typically the ramp platform body pivots between a range of 13 to 17 degrees. The hinging arrangement 40 includes hinge pins 48 and cooperating hinge sleeves 50 that are mounted towards upper adjacent edges of the ramp 5 body 38 and the chassis support beams 52 of the trailer undercarriage. The ramp platform body 38 includes a ramp support 44 towards its rear end for supporting the ramp platform body 38 on the vehicle support surface when the ramp platform body 38 is hingedly displaced to the position in which the ramp 10 platform traverse surface 36.1 inclines downwardly rewards away from the rear end of the load bearing surface 28. The ramp support 44 includes a transverse support wall towards the rear end of the ramp platform body 38 that projects away from the ramp platform body 38 and that defines a platform support surface 46 towards its free end for engaging the vehicle support surface. 15 The support wall 44 is formed integrally with the ramp platform body 38. In other words, it is formed as a part of the structure of the ramp platform body 38 so it depends down below the ramp platform body 38. 20 The transverse support wall 44 towards the rear end of the ramp platform body 38 is sized to have a vertical height so that, when the ramp platform body 38 is supported on the vehicle support surface by the support wall 44, the ramp platform traverse surface 36.1 is positioned at a certain height so that it is spaced away above from the vehicle support surface by a certain distance. The 25 support wall 44 is sized to support the rear end of the platform traverse surface 36.1 at least 0.4 m above the vehicle support surface when the ramp support surface 46 of the support wall 44 abuts the vehicle support surface. The other ramp part 34 includes two laterally spaced elongated ramp track 30 members 52, 54 defining track traverse surfaces 36.2 between leading ends and trailing ends and transversely spaced long sides. The ramp track members 52, 54 are displaceable in a translational fashion rearward away from the ramp 15 platform body 38 for increasing the effective traverse surface 36 of the ramp body 38 in a rearwards direction. Thus, the track traverse surfaces 36.2 of the ramp track members 52, 54 5 overlap the platform traverse surface 36.1 when the ramp track members are retracted towards the ramp platform body 38, and are exposed when the ramp track members 52, 54 are displaced rearwards away from the ramp platform body 38 to increase the effective traverse surface 36. 10 The ramp platform body 38 is generally box-shaped and includes an interior defined between a top wall and transversely spaced side walls. The ramp track members 52, 54 are received within the interior of the ramp platform body 38 when it is retracted so that the track traverse surfaces 36.2 overlap substantially completely with the ramp platform traverse surface 36.1. The ramp track 15 members 52, 54 are operatively able to displace in a translational fashion rearward away from the ramp platform body 38 for increasing the traverse surface 36 of the ramp body 38 generally planar in the rearwards direction. The ramp platform body 38 includes a ramp track support surface over which 20 the ramp track members are displaceable when displaced between the retracted and extended positions. The ramp platform body 38 includes a guiding arrangement, generally indicated by reference numeral 56, for guiding the displacement of the ramp track 25 members 52, 54 between their retracted and extended positions. The guide arrangement 56 includes transversely spaced guide formations and vertically spaced guide formations formed by structural parts of the ramp platform body 38. The guide formations define track traveling paths (see arrow 58) having rearward openings 60 along which the displacement of the ramp extension 30 members 52, 54 are guided between the retracted and extended positions through the rearward openings 60.

16 To this end, the guide formations are sized and shaped to be complementary to the outer sides of the ramp track members 52, 54 for snug sliding fitment of the ramp track members in the guide passages 58. Also, the ramp track support surfaces are defined by the guide formations over which the two ramp track 5 members 52, 54 are slidingly displaceable when displaced between the retracted and extended positions. Each ramp track member 52, 54 includes an elongated generally flat box shaped body 62 having a longitudinally tapered rear end portion 66 defining a 10 transverse taper portion face 64 at a taper angle that enables the taper end portion face 64 to lie flat on the vehicle support surface, in use. The other ramp part 34 also includes a bridging member 68 in the form of a brace extending transversely between the ramp track members 52, 54 for 15 holding the ramp track members 52, 54 together in a fixed spatial relationship to each other. The brace 68 includes a mounting flange 70 projecting forwardly from a position intermediate transverse ends of the brace 68. The trailer 22 also includes a ramp platform drive means 72 for driving the ramp 20 platform body 38 pivotally about the hinge axis 42. The ramp platform drive means 72 includes two laterally spaced hydraulic actuators or rams 74 mounted between mounting brackets 76 provided on the undercarriage of the trailer vehicle 22 and mounting brackets 78 provided on the ramp platform body 38, for displacing the ramp platform body 38 pivotally about the hinge axis. 25 Further, the trailer 22 includes drive means 80 for the ramp track members 52, 54 in the form of a hydraulic actuator or ram for displacing the ramp track members 52, 55 towards and away from the ramp platform body 38 between the extended and retracted positions along the ramp member traveling paths 30 58. The ramp platform body includes two forwardly projecting transversely spaced arms 82, 84 and a brace member 86 extending there between. The hydraulic actuator 80 is mounted between the associated brace member 86 and 17 mounting flange 70 projecting from the brace 68 of the ramp track members 52, 54. The trailer 22 includes a user control arrangement 88 for controlling the 5 activation of the hydraulic actuators 74 and 80 independently, so that the ramp track members and the ramp platform body are controllable independently from each other. The control arrangement includes control pendants 90 that are interfaced with the hydraulic system of the trailer and that are carried on a side of the trailer 22 near a rear end of the trailer 22. 10 The trailer 22 further includes a locking arrangement, generally indicated by reference numeral 92, for releasably locking the ramp platform body 38 in either one of the inclined or horizontal positions. The locking arrangement 92 includes two vertically offset transversely open apertures 94 defined by a rear end of the 15 support beams 52 of the trailer 22 that are associated with the inclined position and the horizontal position of the ramp platform body 38 respectively. The ramp platform body 38 includes vertically extending locking brackets 39 that define an aperture 98 there through and that is displaceable with the ramp platform body for registering with either one of the apertures 94 in the inclined or horizontal 20 positions, as the case may be. The locking arrangement also includes a locking pin 100 for passing through the registering holes, the locking pin being controlled by retraction or extension from a hydraulic booster unit 102 for positively locking the ramp platform body 38 relative to the undercarriage of the trailer 22. 25 The trailer vehicle 22 also includes a raised support body portion 104 toward a leading end of the load support body 24. This includes a fifth wheel for pivotally mounting over the rear axle of a towing rig in the usual way. 30 In use, if a user whishes to load a ground engaging vehicle such as a earthmoving machine on the loading bed 24 of the trailer 22, a user selects the appropriate control from the controls 90.

18 This retracts the pin 100 out of the locking pin apertures 98, 94 so that the platform body 38 is free to pivot about the hinge axis 42 relative to the loading deck 24. 5 The user then actuates the hydraulic rams 74 of the ramp body drive arrangement 72 (using the controls 90) for displacing the ramp platform body 38 hingedly towards the vehicle support surface until the support surface 46 of the support wall 44 engages the vehicle support surface. At this stage, the 10 associated locking pin apertures register with each other and the locking pin100 is inserted into the registering holes for holding the ramp platform body 38 in its inclined position. The traverse surface 36.1 of the ramp platform body now inclines rearwards from the load bearing surface 28. However the traverse surface 36.1 remains spaced away from the vehicle support surface or ground. 15 The user then selects the appropriate control 90 and activates the hydraulic ram 80 of the track member drive arrangement which causes the ramp track members 52, 54 to be displaced in a translational fashion out of the ramp platform body 38. The track members 52, 54 are displaced away from the ramp 20 body 38 until their wedge portions 66 engage the ground. An earthmoving machine to be loaded on the trailer can now be driven up the ramp arrangement over the traverse surface 36 onto the loading deck 24. Once the earthmoving machine is loaded onto the deck 24, the user can retract the 25 hydraulic ram 80 so that the ramp track members 52, 54 are retracted into the ramp platform body 38. The locking pin 100 is then retracted and the ramp platform body is displaced hingedly to its horizontal position. Thereafter the locking arrangement is activated by the user, to lock the ramp platform body 38 in its horizontal position. The above steps are repeated when the time comes to 30 offload the earthmoving machine.

19 An advantage of the trailer 22 is that the ramp track members 52, 54 are stowed generally horizontally, either projecting rearwards or retracted within the ramp platform body 38. This way, the traverse surfaces 36.2 of the ramp track members 52, 54 do not the forward traveling direction of the trailer vehicle. 5 Thus they do not cause any drag resistance particularly when the trailer 12 is traveling along the road at speed. A further advantage is that the ramp track members can be easily and efficaciously moved from the inoperative to the operative positions in use by 10 activating hydraulic rams. Further the actual extent of movement required to change between the operative and inoperative positions is not very great. A yet further advantage is that the illustrated embodiment is very reliable in operation. A further advantage of the arrangement described above with reference to the 15 drawings is that the platform support wall 44 provides load bearing support for a load, such as an earthmoving machine, when it travels over the ramp, at a point intermediate the rear end of the main load support and the free end of the ramp extension member. This acts to relieve the moment applied to the rear end of the main load support, in use 20 It will of course be realized that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set 25 forth.

Claims

1. A trailer vehicle that includes: a main load support having a load bearing surface; and 5 a ramp arrangement having a ramp body including at least two parts defining a traverse surface, one ramp part being pivotally mounted on the main load support for displacing the traverse surface of the ramp body pivotally relative to the load bearing surface of the main load support, and the other ramp part being mounted on the one ramp part and being displaceable relative to the 10 one ramp part for increasing or decreasing the traverse surface of the ramp body.

2. A trailer vehicle as claimed in claim 1, in which the one ramp part is pivotally mounted about a transverse pivot axis towards a rear end of the main 15 load support so that the ramp platform is pivotally displaceable about the pivot axis between a position in which the traverse surface inclines downwardly away from the main load support and a another position in which the traverse surface extends generally planar with the load bearing surface. 20

3. A trailer vehicle as claimed in claim 1 or claim 2, in which the other ramp part is mounted on the one ramp part and being displaceable relative to the one ramp part in a direction in which the traverse surfaces of the one part and the other part overlap progressively more for decreasing the effective traverse surface of the ramp body and a opposite direction in which the traverse 25 surfaces overlap progressively less for increasing the traverse surface of the ramp body.

4. A trailer as claimed in claim 3, in which the other ramp part is displaceable translationally rearward away from the one ramp part for 30 increasing the traverse surface of the ramp body in a rearwards direction. 21

5. A trailer vehicle as claimed in any one of the preceding claims, in which the main load support includes an elongated load support body having a generally rectangular flat load bearing surface defined longitudinally between a leading end and a trailing end of the load support floor and transversely spaced 5 lateral long sides of the floor.

6. A trailer vehicle as claimed in any one of the preceding claims, in which the one ramp part includes a generally rectangular ramp platform body defining a generally flat ramp platform traverse surface between its leading end and 10 trailing end and between transversely spaced lateral sides.

7. A trailer vehicle as claimed in claim 6, in which the one ramp part includes a hinging arrangement for mounting the ramp platform body about a transverse hinge axis towards the rear end of the elongated load support body, 15 the ramp platform body being hingedly displaceable about the hinge axis between a position in which the ramp platform traverse surface inclines downwardly rewards away from the rear end of the load bearing surface and another position in which the ramp platform traverse surface extends horizontally generally planar with the load bearing surface. 20

8. A trailer vehicle as claimed in claim 7, in which the vehicle is supported on a vehicle support surface, the ramp platform body including a ramp support towards its rear end for supporting the ramp platform body on the vehicle support surface when the ramp platform body is hingedly displaced towards the 25 position in which the ramp platform traverse surface inclines downwardly rewards away from the rear end of the load bearing surface.

9. A trailer vehicle as claimed in claim 8, in which the ramp support includes a transverse support wall towards the rear end of the ramp platform body that 30 projects way from the ramp platform body and that defines a platform support surface towards its free end for engaging the vehicle support surface. 22

10. A trailer vehicle as claimed in claim 9, in which the transverse support wall towards the rear end of the ramp platform body is sized to support the rear end of the ramp platform body in a position in which the rear end of the ramp 5 platform traverse surface is spaced away above from the vehicle support surface when the ramp support surface abuts the vehicle support surface.

11. A trailer vehicle as claimed in claim 10, in which the other ramp part includes two laterally spaced elongated ramp track members defining track 10 traverse surfaces between leading ends and trailing ends and transversely spaced long sides, the ramp track members being displaceable translationally rearward away from the one ramp part for increasing the traverse surface of the ramp body in a rearwards direction. 15

12. A trailer vehicle as claimed in claim 11, in which the ramp track members are received within the ramp platform in a retracted position in which track traverse surfaces overlap substantially completely with the ramp platform traverse surface, and operatively able to displace translationally rearward away from ramp platform body for increasing the traverse surface of the ramp body 20 generally planar in the rearwards direction.

13. A trailer vehicle as claimed in claim 12, in which the ramp track members are sized to project rearwards away from the ramp platform body so that the track traverse surface extends generally planar between the rear end of the 25 platform traverse surface and the vehicle support surface.

14. A trailer vehicle as claimed in claim 13, in which the ramp platform body includes a ramp track support surface over which the ramp track members are displaceable when displaced between the retracted and extended positions. 30

15. A trailer vehicle as claimed in claim 14, in which the ramp track support surface includes two parallel transversely spaced sliding surfaces over which 23 the two ramp track members are slidingly displaceable when displaced between the retracted and extended positions.

16. A trailer vehicle as claimed in claim 15, in which the ramp platform body 5 includes a guiding arrangement for guiding the displacement of the ramp extension members between the retracted and extended positions.

17. A trailer vehicle as claimed in claim 16, in which the guide includes transversely spaced guide formations and vertically spaced guide formations 10 defining between them a track traveling path along which the displacement of the ramp extension members are guided between the retracted and extended positions.

18. A trailer vehicle as claimed in claim 17, in which the guide formations are 15 sized and shaped complementary to the outer sides of the ramp track members for snug sliding fitment of the ramp track members in the guide passages.

19. A trailer vehicles as claimed in claim 18, in which the other ramp part includes a bridging member extending transversely between the ramp track 20 members for holding the ramp track members together in a fixed spaced relationship to each other.

20. A trailer vehicle as claimed in claim 19, in which each ramp track member includes an elongated generally flat box-shaped body having a 25 longitudinally tapered rear end potion defining a transverse taper portion face at an taper angel that enables the taper end portion face to lie flat on the vehicle support surface, in use.

21. A trailer vehicle as claimed in claim 20, which includes a ramp platform 30 drive means for driving the ramp platform pivotally about the hinge axis. 24

22. A trailer vehicle as claimed in claim 21, in which the ramp platform drive means includes two laterally spaced hydraulic actuators mounted between an undercarriage of the trailer vehicle and the ramp platform body, for displacing the ramp platform pivotally about the hinge axis. 5

23. A trailer vehicle as claimed in claim 21, which includes ramp track members drive means for displacing the ramp track members towards and away from the ramp platform body between the extended and retracted positions along the ramp member traveling path. 10

24. A trailer vehicle as claimed in claim 23, in which the ramp track member drive means includes a hydraulic actuator mounted between the ramp platform body and the bridging member extending transversely between the ramp track members. 15

25. A trailer vehicle as claimed in claim 23, which includes a locking arrangement for locking the ramp platform body in the position in which the ramp platform traverse surface inclines downwardly rewards away from the rear end of the load bearing surface or in the other position in which the ramp 20 platform traverse surface extends horizontally generally planar with the load bearing surface.

26. A trailer vehicle as claimed in claim 25, in which the locking arrangement includes at least two vertically offset transversely open apertures defined by a 25 rear end of the undercarriage of the vehicle and that are associated with the inclined position and the horizontal position of the ramp platform body respectively, and a locking pin transversely retractably displaceable into the apertures at the respective positions for positively locking the ramp platform body reality to the undercarriage of the vehicle. 30 25

27. A trailer vehicle as claimed in claim 26, which includes at least one user controller unit interfaced with a hydraulic system of the trailer vehicle for controlling the hydraulic actuators and the locking arrangement. 5

28. A trailer vehicle as claimed in claim 27, in which the undercarriage of the trailer vehicle includes two transversely space parallel elongated support beams extending longitudinally between a rear end and a front end of the main load support body. 10

29. A trailer vehicle as claimed in claim 28, in which the elongated load support body includes a raised support body portion toward a leading end of the load support body.

30. A trailer vehicle as claimed in claim 30, in which the trailer vehicle is a 15 heavy duty trailer and includes a coupling arrangement for coupling to a fifth wheel hitch of a tractor vehicle.

31. A ramp arrangement for a vehicle having a main load support, the ramp arrangement including: 20 a ramp platform that is pivotally mounted about a lateral pivot axis towards a rear end of the main load support, the ramp platform being pivotally displaceable between a loading position in which it inclines downwardly away from the main load support and a travelling position in which it extends generally horizontally; and a ramp extension member having a ramp platform 25 end and a free end mounted on the ramp platform, the ramp extension member being translationally displaceable between a retracted position in which it overlaps with the ramp platform and an extended position in which it projects out of the ramp platform in a rearward direction. 30

32. A road going vehicle including a main load support; and 26 a ramp arrangement including a ramp platform that is pivotally mounted about a lateral pivot axis towards a rear end of the main load support, the ramp platform being pivotally displaceable between a loading position in which it inclines downwardly away from the main load support and a traveling position in 5 which it extends generally horizontally; and a ramp extension member having a ramp platform end and a free end mounted on the ramp platform, the ramp extension member being translationally displaceable between a retracted position in which it overlaps with the ramp platform and an extended position in which it projects out of the ramp platform in a rearward direction. 10

33. A vehicle according to claim 32, wherein the vehicle is a truck.

34. A trailer substantial as herein described in the detailed description of the invention with reference to Figures 2 to 16. 15