AU2013205069A1 - Rear Loading Tilt Trailer Assemblies - Google Patents

Abstract

This invention provides a rear loading tilt trailer assembly [10] which has a trailer body [11] which can tilt about the trailer wheels between a substantially horizontal travelling attitude and a tilted loading attitude. The trailer body [11] is connected by a gooseneck coupling [14] to a prime mover [16] above the rear wheels thereof through a three axis towing connection. The gooseneck coupling [14] connects at its rear lower end to the front of the trailer body [11] through a transverse hinge pin [32] whereby the trailer body [11] can pivot relative to the gooseneck coupling [14] and thus tilt about the trailer wheels between the loading and unloading attitudes. to effect a compensatory relative rearward movement of the trailer body [11] during tilting which also results in a forward movement of the front upper end of the gooseneck coupling [14]. This maintains the trailer wheels a constant distance from the prime mover wheels during tilting enabling the prime mover and the trailer brakes to be kept on. .. .. . ....... .... ........................... ................................. ...................... .................... ........ ...................... .. .. .................... ........................................... ............. ................... ............................ - - .......... .................................. ................... ............... ............................... ......................... .......... ................. ............ .................. . ... .......... ................... ................. .......... ........ ... . . ........ .. ....... ... ........... ............................... ............................................. . .... ...... ... ... .... ... ......... .... ......... ......... -- .... ...... .............. .......... ............. .................... ... ............. ......................... ................... ............... ....................... ............................ .................................................. ............... ................................................................. ... ............. ............................. ............... .................. ........................... ............................. ...... .................... ......................................... ...... ........... ............ ..................................................................... .............. ......................... ..................................................... ...................................... ........... ............................................ ...... ......... ............. ........... .............................................................. ..................................... ........... ............................. ................. ........... ........................... ................ ... ......... .................. .................. .................. ............ .......... ......................... ............ ................... ................................. ..... . ..... ........... ........... .... ........ ...... ............ . ... .. .... ... .......... ....... ......... ... ...... .. . ......... ... ........................... .............. ..... ...... ................... .... ........ ......................... ..... ........................ .... ....... ... ........... ...... ............. .............. .... ...... ..... ..... .... ... ... .... ............ . .......... ............ .......... ........ ........ ... . ................... .................. .......... .............. ............ ....... ............... .... ...... ...... ....... ........ ..... .............................. ............................ .... . ..... ............................... .... ................................ ...................................................... ........... .................................. ..... ................................. .................................................. - ...... - .... ................................... - - . ............... ................................................

Description

TITLE Rear loading tilt trailers assemblies. TECHNICAL FIELD This invention relates to rear loading tilt trailers and it has particular application in the mining industry for off-road trailers which may be utilised for haulage of mining equipment on mine sites. However this invention may also be applied to road trailers. Heavy haulage off-road loader trailers are utilised in the mining industry to carry large tracked equipment such as dozers, drills and excavators, which may weigh several hundred tons tonnes, from one worksite to another. Typically such trailers have pneumatic tyres so they can be trailed for long distances without damaging the load or the road. Such trailers are also utilised for carrying rubber tyred vehicles where the tyres are not capable of running for long distances due to overheating. The operating cost of such tracked mining machines is high and any delay to mining operations caused by their operational absence can be extremely expensive. Thus it is necessary that the trailers which move them around can be loaded and unloaded efficiently and that they operate reliably. Furthermore if repair is necessary, simplicity of construction and operation enables repair downtime and costs to be minimised. BACKGROUND ART Several different types of off-road trailers are used in the mining industry. They include trailers which utilise multiple rows of smaller tyred wheels disposed under the trailer deck and having a rigid goose-neck attachment for connection to the prime mover. In use, many of the wheels of these types of trailers are dragged sideways during turning causing considerable wear. Furthermore the elevated trailer deck necessitates the use of loading ramps which may be too steep for some equipment such as drills which may have large overhangs. Heavy haulage off-road trailers are also provided which utilise large diameter pneumatic tyred wheels of a size similar to the prime mover, both in single or double rows, where the wheels are not arranged under the load supporting deck of the trailer. These types of trailers typically provide means for lowering one end or the other to the ground to enable vehicles to be driven to and from the load supporting deck. Such trailers as illustrated in US patents 3536340, 3698582, 4390192, 4413836 and 6932372 include arrangements in which the trailer goose-neck attachment to the prime mover may be detached from the trailer deck to enable trailer loading to and from the lowered front of the trailer deck. A disadvantage of such trailers is their complexity and the need to disengage and re-engage the goose neck assembly with the trailer deck for each loading and unloading operation. Trailers are also provided which remain fixed to the prime mover while the rear of the trailer deck is lowered to rest onto the ground. In such arrangements the rear of the trailer is supported by large diameter wheels independently mounted at each side of the deck whereby they may be pivoted outwards and upwards to enable the trailer deck to engage the ground and to provide a relatively unobstructed path to and from the deck. For this purpose the trailer deck is provided with an integral ramp which is lowered to the ground using large in built jacks. While these types of trailer are effective in use they are relatively complex and expensive to manufacture. In a further simpler arrangement the trailer deck is supported by large diameter wheels at each side of the trailer deck and the trailer is attached to the prime mover by a height adjustable coupling which may be operated to pivot the deck about the trailer wheels until its rear end engages the ground to enable the payload to be driven onto and from the trailer between the wheels. A load limitation of this arrangement is determined by the lateral spacing of the trailer wheels between which the load must be driven to and from the trailer. While this type of off-road trailer offers simplicity, economy of construction and ease of loading and unloading compared to the aforementioned types, a disadvantage is that the height adjustable trailer coupling is disposed behind the rear wheels of the prime mover such that a reduced proportion of the trailer load is transferred to the rear of the prime mover compared to a trailer utilising a gooseneck type coupling. This reduces the traction available at the rear drive wheels of the prime mover and this coupled with the rear set coupling makes jack-knifing more likely to occur in use. This invention aims to provide a rear loading tilt trailer assembly which will be reliable and efficient in use and which will alleviate at least one of the disadvantages associated with the presently available rear loading tilt trailers. Other objects and advantages of this invention will hereinafter become apparent.

SUMMARY OF INVENTION With the foregoing in view, this invention in one aspect resides broadly in a rear loading tilt trailer assembly including: a trailer body having a load deck disposed below the upper extremities of the trailer wheels and onto which deck a vehicle to be loaded or unloaded may be driven between the trailer wheels to or from the tilted trailer body across the lowered rear end thereof; a gooseneck coupling which connects at its rear lower end to the front of the trailer body through a transverse pivot connection which permits the trailer body to pivot between its substantially horizontal travelling attitude and its tilted loading attitude about the trailer wheels and relative to the gooseneck coupling, and a towing connection at the front elevated end of the gooseneck coupling for connecting the trailer assembly to a prime mover above the rear axle thereof. Pivoting of the trailer body about the trailer wheels could be controlled entirely by the position of a vehicle on the trailer body. For example the trailer wheels could be positioned so that the weight of the trailer bed caused pivoting of the unladed trailer to a tilted loading attitude and the travel of a vehicle up the tilted trailer bed beyond the wheels utilised to pivot the trailer about the trailer wheels to its travelling attitude. Preferably however the trailer wheels are disposed toward the rear of the trailer bed and a hydraulic ram is connected between the gooseneck coupling and the trailer deck for pivoting the trailer deck from the travelling attitude to the tilted attitude. The rearward positioning of the trailer wheels beneficially increases the proportion of the trailer load applied to the prime mover as well as biasing the empty trailer to a travelling position. The limit of movement of this ram in one direction could act as a stop preventing tilting of the trailer body from its tilted loading attitude and beyond its travelling attitude or the ram could be provided with hydraulic locking means for limiting the pivotal movement of the trailer body beyond the travelling position. Locating the trailer wheels further back toward the rear of the trailer body increases the vertical load applied to the prime mover through the gooseneck coupling which is suitably disposed ahead of the rear axle of the prime mover for a more effective towing geometry. Furthermore the hydraulic ram could be used as a damper to control the rate of pivotal movement between the tilted and travelling attitudes of the trailer body or to cushion the engagement of the gooseneck coupling with any limiting means utilised to hold the trailer body in the travelling attitude. The limiting means could be provided as a fixed maximum length sliding or pivoting linkage or a chain connected between the gooseneck coupling and the trailer deck remote from the pivotal connection therebetween. The stop means could also be a pin or pins engageable with apertures in the gooseneck coupling and the trailer body which align in the travelling position. Of course other latching means could be utilised if desired. Preferably the limiting means is constituted by a rear facing abutment formed on the upstanding part of the gooseneck coupling and a complementary forwarding facing abutment provided on tower means disposed at the front end of the trailer body whereby the relatively movement between the gooseneck coupling and the trailer body is positively stopped when the trailer body pivots to its travelling position. More preferably the abutment is formed on an upper portion of the rear upstanding part of the gooseneck coupling and the tower means such that the abutments are sufficiently spaced from the transverse pivot connection to reliably cope with repeated applications of the engagement loads thereto which may result for example from driving a heavy vehicle onto the trailer deck past the trailer wheels causing the trailer deck to pivot rapidly, this rapid pivotal movement being stopped by impact between the abutments. In a preferred embodiment of the invention the pivotable gooseneck has an elongated upper portion whereby the towing connection is positioned above the rear axle of the prime mover and forwardly thereof so as to increase the dynamic stability of the linked prime mover and trailer assembly during towing operations, especially when heavily loaded. While the pivot connection between the gooseneck coupling and the trailer body could be in the form of a universal connection it is preferred that it be formed as a transverse hinge connection which may be formed by a hinge pin passing through suitable bearings provided in the lower part of the tower means and the lower rear end of the gooseneck coupling. The gooseneck coupling to the prime mover is suitably a universal connection of the type typically provided in the heavy haulage applications and having vertically spaced pivot axes disposed at right angles to one another. It is preferred that the transverse pivot axis of this universal connection with the prime mover be the lower pivot of the universal connection and that the hinge connection between the gooseneck with the trailer body be disposed at a level adjacent the top of the trailer deck but beneath the level of the transverse pivot axis of the universal connection to the prime mover. This arrangement maintains the distance between the prime mover wheels and the trailer wheels substantially constant during tilting operations. With other forms of trailer couplings, the trailer wheels would normally be drawn forward toward the hinge connection when the trailer is pivoted upwardly at the front end. However according to one aspect of this invention the corresponding upward pivoting of the rear lower end of the gooseneck coupling is accompanied by a rearward movement thereof relative to the prime mover which substantially compensates the forward movement of the trailer during tilting. The prime mover wheels and the trailer wheels thus remain substantially the same distance apart and there is minimal rotation of the trailer wheels or the prime mover wheels caused by tilting of the trailer. Any forward movement of the trailer wheels relative to the prime mover which results from tilting will vary with the tilt angle of the trailer deck and compensation is provided according to one aspect of this invention by the geometrical arrangement of the three axis universal connection and the transverse pivot connection to substantially equalise the forward movement of the front end of the gooseneck with the rearward movement of the rear end of the gooseneck. The slight relative movement of the trailer wheels toward the prime mover which results from the tilt angle of the trailer body can also be substantially compensated if desired. Without substantial forward movement of the trailer wheels during tilting, the trailer brakes and the prime mover brakes may be applied at all times during loading and unloading without placing undue stress on the tyres through skidding or upon engagement of the rear of the trailer with the ground. This feature also increases the safety during loading and unloading operations, especially on an incline, as the trailer and prime mover brakes may be engaged throughout the operation. This is in contrast to some of the simpler types of tilting trailers where the trailer brakes have to be released to enable the supporting wheels to rotate to accommodate a longitudinal movement of the trailer during these operations. In order to transfer some of the braking effort from the prime mover to the trailer during tilting operations locking means may be provided to lock the gooseneck coupling to the trailer body at any selected angle of tilt. The hydraulic ram connected between the trailer deck and the gooseneck coupling could be used for this purpose.

The gooseneck member of the gooseneck coupling could be formed with the rear upstanding part bifurcated so as to straddle a central tower means on the front of the trailer body and, if utilised, a single hydraulic ram could connect between the gooseneck coupling and the tower means. Alternative the rear upstanding part of the gooseneck coupling could provide a nesting arrangement in which the tower means is nested within a rearward opening cavity in the rear upstanding part. Preferably however the tower means is constituted a pair of laterally spaced towers which suitably form the outer mounts of a hinge connection to the lower end of the gooseneck coupling cradled therebetween and constituting the pivot connection between the gooseneck coupling and the trailer body. In this arrangement it is preferred that, if utilised, the hydraulic ram constitute one of a pair of hydraulic rams connect between the gooseneck coupling and each of the respective towers. DESCRIPTION OF EMBODIMENTS In order that this invention be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a typical embodiment of this invention in the form of an off-road rear loading tilt trailer, wherein: Fig. 1 is a side view which illustrates the trailer in the travelling attitude; Fig. 2 is a perspective view of the trailer corresponding to Fig. 1; Fig. 3 is a side view which illustrates the trailer in the tilted loading attitude; Fig. 4 is a perspective view of the trailer corresponding to Fig. 3; Fig. 5 is a perspective view of a further embodiment of the invention; Fig. 6 is a side view of the Fig. 5 embodiment illustrating a drill rig being loaded onto the trailer; Fig. 7 illustrates the trailer loaded with the drill rig; Fig. 8 is a perspective view of the gooseneck and tower assembly removed from the trailer body; Fig. 9 is a perspective view of the tower assembly, and Figs. 10, 11 and 12 provide a plan and side views of another embodiment of the invention. Referring to Figs. 1 to 4 of the drawings it will be seen that a rear loading tilt trailer 10 illustrated has a relatively low trailer body 11 supported by a pair of dual wheels 12 adjacent its rear end 13 and by a gooseneck coupling 14 at its front end 15 which is attached to a prime mover 16 through a three axis hitch 17 which mounts on the prime mover ahead of and above the rear drive axle 18.

In this embodiment the trailer wheels 12 are the same diameter as the wheels 19 of the prime mover and are supported rotatably on respective wheel mount structures 20 mounted to the trailer body 11 at opposite sides thereof. Trailer wheel brakes 21 are provided which may be applied remotely from the driver's cab of the prime mover 16 in known manner. The trailer wheels 12 are offset toward the rear of the trailer body 11 such that the payload, not shown, may be supported forwardly of the wheels 12 with the weight thereof partially taken by the prime mover 16 through the gooseneck coupling 14 and to provide a rear overhanging deck portion 22 which may pivot down about the wheels 12 to engage the ground, as illustrated in Fig. 3. The overhanging deck portion 22 is tapered at its rear end to form an integral ramp 23 to assist loading and unloading in the tilted attitude. In this embodiment the gooseneck coupling 14 includes the rigid gooseneck 30 formed as a box section and provided with a support bearing, shown dotted at 31 in Fig. 1, at its rear lower end for accommodating a hinge pin 32 supported between the towers 40 and a further upright support housing 33 at its front end providing an upper pivot mounting for the three axis connection 17 which connects the gooseneck 30 to the prime mover 16. The lower end of this connection 17 provides a transverse pivot mount 34 to the prime mover 16 and the upper end of the connection 17 includes a trunnion 36 which engages in the housing 33. The intermediate portions of the connection 17 provide the longitudinal roll pivot 35 arranged with its axis at right angles to the pivot axis of the mount 34 and trunnion 36 to form the three axis connection 17 to the prime mover. The gooseneck 30 also provides respective side mountings 37 for rearwardly extending hydraulic rams 38 and side mounted stops 39 which abut the front faces of laterally spaced towers 40 when in the travelling attitude which are formed integrally with the trailer deck 11. Much of the structure of the trailer body lies beneath the intended track paths where the loads applied by the payload are concentrated, indicated by the shaded areas at 25 and as shown in Fig. 2, the towers 40 extend upwardly from the front end of the trailer deck 11 from respective bases 41 disposed in front of the track paths 25 so that adequate structure is available to make a strong but economical and efficient connections to the trailer deck. Their hinge pin housings 42 formed through the lower ends of the towers 40 accommodate the hinge pin 32 which passes through the bearing 31 in the gooseneck 30. The hydraulic rams 38 connect at their rear ends to the upper ends 44 of the towers 40 and provision is made for inserting a locking pin 45 through an upper end of at least one tower 41 to engage with the gooseneck 30 as a safety lock. The lower transverse pivot mount 34 of the gooseneck coupling 14 has its axis disposed above the axis of the hinge pin 32 and thus in operation tilting the gooseneck 30 to elevate the front end of the trailer for loading/unloading moves the hinge pin 32 upwardly and rearwardly with respect to the three axis connection pivot 34. Locating this hinge pin 32 elevated slightly above the deck of the trailer body 11 in this embodiment results in rearward movement of the lower rear end of the gooseneck 30 which substantially compensates for the relative movement of the wheels toward the hinge pivot 32 as a result of the inclination of the deck 11 and the forward movement of the front end of the gooseneck coupling 14 about the transverse pivot mount 34. By comparing Figs. 1 and 3 it will be seen that the distance between the rear wheels 19 of the prime mover and the trailer wheels 12 as dimensioned at 45 in Fig. 3, remains substantially constant during the tilting operation. This enables the trailer brakes to be maintained applied during loading and unloading operations providing a significant safety advantage to this trailer 10 which has the ability to unload and load relatively safely on an incline such as a ramp, utilising the brakes of the trailer and the prime mover to hold the trailer stationary apart from the tilting during these operations. The rams 38 may be operated from the drivers cab or from a position near the hitch by a remote control to provide an operator with better visibility of the loading operations and may be extended to raise the front end of the trailer deck 11 so as to tilt it to a loading attitude with its integral ramp 23 engaged with the ground or be retracted to return the trailer deck 11 to its travelling position where the stops 39 abut the front face of upper portions of the towers 40. When in the travelling attitude, either loaded or unloaded the rams 38 are not required to carry any load as the dead load will maintain the stops 39 in abutment with the front faces of the towers 40 and this engagement effectively locks the gooseneck coupling to the trailer bed. Furthermore the size of the hydraulic rams 38 need not have the capacity to tilt the trailer bed when the trailer is loaded, as tilting of the trailer deck may be initiated by moving the payload rearward beyond the wheels 12 whereupon the trailer deck will tilt until the ramps 23 engages the ground. The rams 38 may be utilised during this operation to slow down the pivotal movement of the trailer deck as they may be utilised to for the same purpose when loading and utilising the weight of the payload to pivot the trailer deck 11 back to its travelling attitude. In such arrangement the rams 38 are mostly utilised to tilt the unloaded trailer as the weight of the deck alone acting forward of the wheels 12 maintains the deck 11 in its travelling attitude. Of course the rams could be formed with the capacity to tilt the trailer deck when fully loaded. In this respect it will be seen that both the rams 38 and the stops 39 are disposed a significant distance from the hinge pivot 32 so that relatively low forces are required to be accommodated by these members in use. The stops 39 are suitably provided with wear pads and may contain resilient cushioning components if desired. Further the stops could contain compression springs which are compressed when the trailer deck is moved to its travelling attitude so as to assist in the initial opening movement of the gooseneck away from the towers. It will also be seen that with this arrangement the towers, rams and stops are substantially contained within the side profile of the gooseneck 30 ensuring maintenance of clear space in front of the gooseneck for non-fouling operations with the prime mover during all anticipated relative pivotal movement of the trailer body. Further the towers do not substantially intrude into loading area above or beside the tower. The configuration shown utilises dual wheels on the trailer. The overall width of this arrangement could be reduced by using tandem wheel with a rocking beam between them to equalise the tyre loads so as to provide a wider space between the opposite sets of wheels for accommodating the payload or to mount additional wheels. The tilt trailer assembly 50 illustrated in Figs. 5 to 8 functions in the same manner as the tilt trailer assembly 10. However in this embodiment the pairs of trailer wheels 52 at each side of the trailer body 51 are supported by a respective rocking beam 53 which pivot about a common transverse axis disposed towards the rear of the trailer body 51. This arrangement provides a wider load deck between the wheels 52 such as for loading a tracked drill rig 54 as illustrated in Figs. 6 and 7. In addition the gooseneck coupling 67 is formed as a removable gooseneck and tower assembly 55 which may be readily removed from the trailer deck 51 to facilitate separate road transport of the trailer body 51 and the gooseneck assembly 55.

In addition the upper portion 57 of the gooseneck coupling 67 is provided with a ballast chamber 58 which also forms lateral abutments 59 which engage with complementary abutments 60 provided on the prime mover 61 when the trailer is pivoted to its maximum pivot angle relevant to the prime mover. The ballast chamber can receive ballast which may be in the form of steel balls and magnetite sand or other suitable ballast to increase the load on the rear wheels of the prime mover to assist in traction. Referring particularly to Fig. 8 it will be seen that the removable gooseneck and tower assembly 55 includes a pair of towers 62 which extend upwardly in spaced apart relationship from respective base portions 63 which are interconnected by tubular spacer bars 64 whereby the base of the gooseneck and tower assembly 55 may be through bolted to channel shaped extensions 65 of the trailer body 51 for removal and re-assembly operations. Hydraulic rams 56 connect the upper ends of the towers 62 to the gooseneck 67. A hinge pin housing 66 is provided in each tower 62 whereby the gooseneck 67 may be supported between the towers 62 by a hinge pin 68 passing through a pivot housing shown in dotted outline at 70 formed in the lower rear end of the gooseneck 67. In this embodiment the abutments 71 fixed to the gooseneck 67 about complimentary faces 72 on the towers 62 and a locking pin (not shown) operated by the hydraulic ram 74 supported on the gooseneck is adapted to pass through the apertured extensions 75 provided on the towers 62 just beneath the abutments 71. The three axis connection 77 is made as in the previous embodiment with the upright axis trunnion being located in the bearing housing 78 provided that the upper front portion of the gooseneck 67. A significant advantage provided by trailers according to this invention is illustrated in Fig. 6 where it will be seen that a large vehicle with low approach angles can be readily loaded onto the trailer assembly by driving to and from its loaded and unloaded position. The tilt trailer assembly 80 illustrated in Figs. 10 to 12 is adapted for connection to a modified conventional road type prime mover 81. In this embodiment the three axis hitch 82 is positioned on the prime mover chassis above the wheels 83 and offset toward the front axle of the dual rear axle assembly 84. Accordingly the elongated upper portion 85 of the gooseneck 86 is relatively long and the laterally spaced towers 87 between which the gooseneck 86 is supported are both in the form of levers which extend upwardly and forwardly from the trailer body 88 so as to provide forward mountings for the laterally spaced hydraulic rams 89 which extend therefrom down to lateral extensions 90 provided at the front end of the gooseneck 86 as illustrated in Fig. 10. These rams 89 are extended in use to tilt the trailer body about the trailer wheels 91 as illustrated in Fig. 11 and retracted to secure the trailer body in its travelling attitude as illustrated in Fig. 12. It will of course be understood that the above has been given only by way of illustrative example of this invention and that all such modifications and variations in addition to those described, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of this invention as is defined in the appended claims.

Claims (15)

1. A rear loading tilt trailer assembly including: a trailer body having a load deck disposed below the upper extremities of the trailer wheels and onto which deck a vehicle to be loaded or unloaded may be driven between the trailer wheels to or from the tilted trailer body across the lowered rear end thereof; a gooseneck coupling which connects at its rear lower end to the front of the trailer body through a transverse pivot connection which permits the trailer body to pivot between its substantially horizontal travelling attitude and its tilted loading attitude about the trailer wheels and relative to the gooseneck coupling, and a towing connection for connecting the trailer assembly to a prime mover above the rear axle thereof at the front elevated end of the gooseneck coupling.

2. A rear loading tilt trailer assembly as claimed in claim 1, wherein the trailer body is weight biased to pivot about the trailer wheels to its travelling attitude and abutments are provided on the gooseneck coupling and on the trailer body which engage to prevent pivotal movement of the trailer body about the trailer wheels from its loading attitude beyond its travelling attitude.

3. A rear loading tilt trailer assembly as claimed in claim 2, wherein the trailer body is weight biased to pivot about the trailer wheels by positioning the trailer wheels toward the rear end of the trailer body.

4. A rear loading tilt trailer assembly as claimed in any one of the preceding claims and including a hydraulic ram connected between the gooseneck coupling and the trailer body for pivoting the trailer body from the travelling attitude to the loading attitude about the trailer wheels.

5. A rear loading tilt trailer assembly as claimed in claim 4, wherein the trailer body is provided with laterally spaced apart towers at its front end between which said transverse pivot connection is formed and wherein said towers extend upward beyond the transverse pivot connection to support the rear end of said hydraulic ram.

6. A rear loading tilt trailer assembly as claimed in claim 5, wherein said towers are removably connected to said trailer body.

7. A rear loading tilt trailer assembly as claimed in claim 5 or claim 6, wherein said abutment on said trailer body is supported on said towers and adjacent the upper ends thereof.

8. A rear loading tilt trailer assembly as claimed in any one of the preceding claims, wherein said gooseneck coupling has an elongated upper portion whereby said towing connection may be positioned above said rear axle and forwardly thereof.

9. A rear loading tilt trailer assembly as claimed in claim 8, wherein said elongated upper portion includes laterally extending stops which cooperate with stops on a prime mover to limit the rotation of the trailer assembly relative to the prime mover.

10. A rear loading tilt trailer assembly as claimed in claim 8 or claim 9 and including ballast support means associated with elongate upper portion.

11. A rear loading tilt trailer assembly as claimed in any one of the preceding claims, wherein the trailer connection is a three axis connection having an upper part supported at the front of said gooseneck coupling, a lower part connected to said prime mover for pivotal movement about a transverse axis and said upper and lower parts being interconnected for pivotal movement about a longitudinal axis and wherein said transverse pivot connection between said gooseneck coupling and said trailer body is disposed at a level below said prime mover axle to effect compensatory relative rearward movement of the trailer body when pivoting of the three axis towing connection about its transverse pivot axis through tilting of the trailer body moves the upper end of the gooseneck coupling forward.

12. A rear loading tilt trailer assembly as claimed in any one of the preceding claims, wherein the trailer body is connected to the trailer wheels for tilting relative thereto about a common wheel support axis.

13. A rear loading tilt trailer assembly as claimed in claim 12, wherein said common wheel support axis is fixed relative to said trailer body.

14. A rear loading tilt trailer assembly which may be loaded and unloaded with the prime mover and the trailer brakes applied without causing undue stress on the braked wheels and including a trailer body providing a load deck disposed below the upper extremities of the trailer wheels and onto which deck a vehicle to be loaded or unloaded may be driven between the trailer wheels to or from the tilted trailer body across the lowered rear end thereof and a gooseneck coupling which connects at its rear lower end to the front of the trailer body through a transverse pivot connection whereby the trailer body may pivot between its travelling and loading attitudes about the trailer wheels and relative to the gooseneck coupling which connects at its front elevated end to a prime mover above the rear axle thereof through a towing connection, wherein the trailer connection is a three axis connection having a lower part connected to said prime mover for pivotal movement about a transverse axis and wherein said transverse pivot connection between said gooseneck coupling and said trailer body is disposed at a level below said prime mover axle to effect compensatory relative rearward movement of the trailer body when pivoting of the three axis towing connection about its transverse pivot axis moves the upper end of the gooseneck coupling forward.

15. A rear loading tilt trailer assembly substantially as hereinbefore described with reference to the accompanying drawings.