BACKGROUND OF THE INVENTION

The present invention relates to improvements in transport trailers. In particular the invention relates to improvements in an articulation joint for the drawbar connector of a transport trailer and a trailer having a variable length. The invention has particular reference to a trailer having a variable car carrying capacity though it is to be understood that it has application to the transport of other goods including other vehicles such as boats. The articulation joint can also be employed with trailers whether of a single deck or double deck construction or having an enclosed body.

BACKGROUND ART

Road transport vehicles having a car carrying capacity of up to eight motor vehicles are known arranged in a double decker configuration. Other transport vehicles are known which include a trailer with an articulation joint or drawbar connector. Several of these "articulated" trailers may be combined in the one vehicle to provide a "road train". These "articulated" trailers are used for the transport of livestock or bulk shipping containers and are of single deck contruction. The chief disadvantages of these trailered units is their manoeuvreability in urban areas. This limits the length of a trailered unit in order that it may negotiate standard roadway widths and corners.

It is also known to have trailers with a variable axle travel with the trailer length remaining SUBSTITUTESHEET

constant.

It is also known to have a hinged ramp for a car carrying transport vehicle which allows vehicles to be loaded onto the carrier or disembarked therefrom while providing a rear gate during transit.

DISCLOSURE OF INVENTION

The present invention seeks to overcome disadvantages in the prior art, or to substantially ameliorate them, and to provide an improved trailer having increased manoeuvreability or load carrying capacity.

According to one aspect of the invention there is provided an articulation joint for a trailer including first bearing" means for motion about a substantially first horizontal axis, and second bearing means for motion about a substantially vertical axis, wherein said first and second bearing means are offset along a second horizontal axis substantially orthogonal to said first horizontal axis.

In accordance with another aspect of the invention there is provided a trailer including a pivoting joint, at least one axle group for supporting said trailer, a chassis member, a chassis sub-frame for supporting said axle group for transferring weight from the chassis member to said axle group, slider means for allowing relative translational movement of said sub-frame along said chassis member between predetermined positions, and means for locking said slider means relative to said chassis member at said predetermined positions.

Preferably, the locking means comprise a series of locking pins operated by hydraulic cylinders.

According to another aspect of the invention there is provided a trailer including a pivoting joint, at least one axle group for supporting said trailer, a chassis member, a chassis sub frame supporting said axle group for transferring weight from the chassis member to said axle group, means for extending the rear of the trailer with respect to said chassis member and means for locking the position of said extension means in an extended or retracted position.

According to another aspect "of the invention there is provided an articulation joint for a trailer including first bearing means for motion about a substantially first horizontal axis, and second bearing means for motion about a substantially vertical axis, said first and second bearing means being offset along a second horizontal axis substantially normal to said first horizontal axis, said second bearing means further including first, second and third vertical bearing means arranged respectively along said vertical axis and displaced successively along said second horizontal axis.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with respect to a preferred embodiment thereof in which:

Figure 1 shows a schematic of a vehicle employing the articulation joint according to the present invention;

Figures 2 (a) and (b) show the articulation joint of Figure 1 in plan and elevation;

Figures 3 (a) and (b) show in an expanded form

the vertical bearings of the articulation joint according to Figures 1 & 2

Figure 4 shows a prior art form of a trailer having a movable axle group;

Figure 5 shows schematically an extendable trailer having a movable axle group according to another embodiment of the invention;

Figure 6 shows a locking mechanism for the embodiment of Figure 5; and

Figures 7(a) and (b) show a rear extender mechanism of another embodiment of the invention with reference to the embodiment of Figure 5.

MODES FOR CARRYING OUT THE INVENTION

As shown in Figure 1 the vehicle 10 comprises a prime mover 12 to which is attached trailer 14. The trailer 14 is connected to the prime mover 12 by a joint 16 constituting a universal joint having offset vertical and horizontal axes according to the invention. In the form shown in Figure 1 the joint 16 has a horizontal pivot 18 forward of the vertical pivot 20. The joint according to the invention may also have the horizontal and vertical axes interchanged from that shown in Figure 1, that is with the vertical pivot ahead of the horizontal pivot.

The joint 16 provides offset pivoting articulation and functions to transfer the vertical trailer load at the joint 16 more closely to the centre of the drive axles of the prime mover 12. This reduces any load increase to the drive axles and also decreases the negative load effect to the steering axle of the prime mover

12,

In addition the trailer 14 comprises a frame 22 and axle group 24.

The articulation joint is shown in more detail in Figures 2 and 3. The horizontal pivot 18 of the joint 16 comprises two radial type bearing assemblies 26, only one of which is shown in Figure 2(a).

Each bearing assembly 26 comprises a pair of taper housings 28 and 30 constituting a two part rubber bearing block retained by a nut and bolt fixture (not shown) extending axially through both housings 28, 30.

The vertical pivot 20 comprises three bearings 32, 34 and 36. The top bearing 32 and the bottom bearing 36 are radial bearings which contain the horizontal forces of the mechanism while the centre bearing 34 is a thrust bearing which transfers the vertical loads imposed by the trailer 14 to the drawbar connector 38.

The horizontal pivot 18 and the vertical pivot 20 are spaced apart along the length of the trailer 14 by the frame 42. The frame 42 is of a generally welded construction of plate members 44, 46 and 48, vertical plate member 50 and spaced horizontal flanges 52, 54, 56, 58 and 60. The flanges 52-60 are welded to the vertical plate member 50. The flange members 52 and

54 support the top bearing 32. The flange 56 supports the central thrust bearing 34, while the lower flanges 58 and 60 accommodate the bottom bearing 36. The structure of each of the bearings 32, 34 and 36 is shown more clearly in Figure 3 and will be described more fully below.

The frame 22 of the trailer 14 terminates at the bearings 32, 34 and 36 in respective frame members 60, 62 and 64.

The respective vertical axes of the bearings 32, 34 and 36 are offset with respect to one another along the third remaining orthogonal axis. The top bearing 32 is thus displaced forward in the direction of the horizontal pivot 16 compared with the central thrust bearing 34, which in turn is forwardly displaced of the bottom bearing 36. This vertical offset articulation induces opposite chassis roll to each of the trailer 14 and the prime mover 12 during any manouevure other than towing in a straight line to enable legal road clearance to be maintained at all times.

Each of the top and bottom bearings 32 and 34 is substantially identical and, as shown more clearly in Figure 3(a) with reference to the top bearing 32, comprises a radial spherical plain bearing 70 supported upon a hollow pivot pin 74. The bearing 70 is held in place by the bearing keeper 76 fixed by fixtures (not shown) to the flange 60. The pivot pin 74 is fitted to the upper and lower flanges 52 and 54 of the frame 42 by respective collars 78 and 80, 82 and 84. Collars 78 and 82 are welded to their respective flanges 52 and 54, while collars 80 and 84 acts as washers. The pin 74 is bolted by nut and bolt 86 to these flanges 52 and 54 between thrust washers 88 and 90.

The central thrust bearing 34 is shown in Figure 3(b) and allows rotational movement between flange 56 and frame member 62. The thrust bearing comprises an outer bearing member 100 held in fixed relation to the frame member 62 by the keeper 102. The keeper 102 and

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the outer member 100 are sealed by O-ring seal 104. The inner bearing member 106 is hollow and is fixed to the flange 56 by the hollow pin 108. Pin 108 is secured to the cylindrical sleeve 110 by the pin rivet 112, while sleeve 110 is welded to the flange 56. The hollow pin 108 is spaced from the sleeve 110 by the spacer 114.

Typically, the horizontal pivot 18 can swivel 15 degrees either side of the vertical axis, while the vertical pivot 20 can swivel 60 degrees either side of the longitudinal axis of the trailer 1*4.

The trailer 14 can also be provided with the means to extend the length of the trailer by moving the axle group 24 rearward with respect to the front of the trailer 14 (or joint 16). In conventional trailers as shown in Figure 4 the axle group 24 can be moved in order to achieve weight redistribution. In such conventional trailers the axle group 24 is moved by sliding under the chassis rails 120. The chassis rails 120 support the frame or deck 122 of the trailer.

In a further aspect of the invention as shown in Figure 5 the axle group 24 is made movable by constructing an integral sub chassis 130 extending the width of the trailer underneath the upper chassis 134. The upper chassis 134 comprises a pair of chassis perimeter beams 136 and 138 extending the length of the trailer and joined by spreader beam 140.

Each chassis perimeter beam 136, 138 can slide on low friction plate 142 with respect to the sub chassis frame 130, as shown more clearly in Figure 6. The low friction plate 142 is made, for example, of ultra high molecular weight polyethylene. The slider mechanism

can be locked in either a retracted or an extended position by means of four locking pins. One such locking pin 144 operated by hydraulic cylinder 146 is illustrated in Figure 6.

Retraction of the pin 144 by hydraulic cylinder 146 allows the sub chassis frame 130 (and thus axle group 24) to move with respect to the upper chassis 134. This movement can be achieved in a number of ways, for example by means of an hydraulic actuator, electric motor or worm drive or the like. In practice, it is most simply achieved by applying the brakes of the wheels of axle group 24 and advancing prime mover 12 to which trailer 14 is attached. Similarly, reversing the prime mover 12 when the axle group 24 is in its extended configuration with its brakes applied contracts the axle group 24 to its retracted position. The slider mechanism can then be locked in place by activating hydraulic cylinder 146 to engage pin 144 in cooperating apertures in members 148 and 150 carried respectively by the chassis perimeter beam 136 and the sub chassis frame beam 152 (and similarly for the other locking pins) .

In addition the present invention provides that the trailer overhang can be increased by extending rearward a rear extender section carried within the chassis perimeter beams 136 and 138. As shown in Figures 7(a) and (b), the rear extender comprises a pair of cantilever beams 160 only one of which is ilustrated in Figure 7(b), each accommodated within chassis perimeter beams 136 and 138 on either side of the trailer's rear. The cantilever beams 160 are joined at the rear by a cross beam member (not shown) . A pair of locking pins, one either side, lock the rear extender beam 160 in either a retracted or an extended position. A lock pin guide 164 aligns each lock pin

166 ^' to ensure a positive engagment of the pin within the hollow member 168 of the extender beam 160. The locking pin 166 can be operated hydraulically, though other methods of activation may be employed, for example an electric motor or other techniques known to a person skilled in the art. Equally the rear extender can be moved manually, hydraulically, or electrically once pin 166 is disengaged from hollow pin member 168.

This rear overhang increases the load carrying length of the trailer beyond the axle group 24. A vehicle with a double decker car trailer can now be configured to carry up to 10 sedans comprising eight sedans of the retracted configuration plus an additional ^' 2 sedans.

The invention relates to a trailer having improvements in either the articulation connector (or joint), movable axle group 24, or extendable rear overhang 25. It is to be understood that a trailer could incorporate any one of these aspects singularly. Thus a standard trailer could be improved singularly by the inclusion of the disclosed articulation drawbar connector. Equally, a trailer having a standard drawbar could incorporate the movable axle group aspect of the current invention, or the extender beam aspect of the invention singularly or in combination. It is also clear that all three aspects can be combined in the one trailer.

The invention provides a trailer that has a greater versatility.

The invention in one form provides a means of increasing the manoeuvreability of a trailered vehicle allowing manoeuvreability comparable to existing

transport vehicles with a longer vehicle when the articulation connection is employed. In addition a variable length trailer can be provided by means of the slider and the variable rear overhang. These elements in combination can then be used to provide a trailer of desired capacity, manoeuvreability and length.

Though the invention has been described above with respect to preferred embodiments thereof it is contemplated that other variations are possible within the knowledge of a person skilled in the art.