METHOD OF MANUFACTURING A TRAILER AND A TRAILER

THIS INVENTION relates to load carrying vehicles. More particularly it relates to a method of manufacturing a trailer and to a trailer.

The Inventor is aware of load carrying trailers which comprise a wheeled chassis on which one or more wheel sets and draught vehicle connection means whereby the trailer is connectable to a draught vehicle are mounted. In view of the fact that the chassis is the load bearing structure it must be capable of withstanding the loads to which the trailer is subjected in use. Accordingly, it tends to be of a relatively heavy construction. More particularly, the chassis typically is constructed from two main chassis beams running longitudinally from front to rear of the trailer and several longitudinally spaced transverse cross beams connected to and extending between the main chassis beams. At a front end thereof there are cross beams onto which a fifth wheel support and pin are connected to the two main chassis beams. At a rear end of the trailer the suspension components are connected onto the two main chassis beams. Several variants are built such as single; double; triple or quadruple axle. The build criteria for all variants are remarkably similar. The cross members that support the floor of the trailer are then laboriously threaded through the upper web of the chassis beams by means of cutting numerous holes through the main chassis beams.

If the trailer is intended for use in transporting bulk transport or shipping containers, mounting formations are provided on the chassis which engage releasbly with complementary standard mounting formations or corner castings at the corners of the bulk transportation container.

If the trailer is a so-called box body trailer having an enclosed load receiving body, it is constructed by fixing a wooden or steel floor to the chassis. The sides or walls of the body are connected to longitudinal members connected to ends of cross- members forming part of the chassis. If desired, a roof is connected to upper edges of the walls of the body.

Problems associated with box body trailers of which the Inventor is aware include that due to the inherent poor connection between the chassis and the box body the entire trailer flexes under load and, ultimately cracks appear in numerous places particularly around a door in the box body and in the main chassis where the cross members pierce through these beams. Further, as a result of space being taken up by the chassis, the centre of gravity of the loaded box body trailer is relatively high which can lead to instability. In addition, manufacturing costs of box body trailers are relatively high. A further problem associated with prior art trailers is that the heavy steel components used in the construction of the chassis account for a significant part of the permitted axle load of the trailer thereby reducing the load carrying capacity of the trailer.

It is an object of the invention to provide means which the Inventor believes will at least alleviate some of these problems.

According to one aspect of the invention there is provided a method of manufacturing a box body trailer which includes the step of securing at least one wheel set and a draught vehicle connection means to a preformed load receiving body so that the body forms the load bearing structure of the trailer.

In a preferred embodiment of the invention, the pre-formed load receiving body includes at least one bulk transportation or shipping container.

The method may include inverting the bulk transportation container and securing the at least one wheel set and the draught vehicle connection means at spaced apart positions to an operatively underside of the at least one transportation container.

The body may include at least two bulk transportation containers, the method including the step of securing the bulk transportation containers together end-to-end to form the body.

The method may include securing the draught vehicle connection means to one of the bulk transportation containers and securing the wheel set to at least the other container.

The method may include securing the wheel set to both of the bulk transportation containers.

The method may include securing the wheel set to the or each bulk transportation container releasably making use of twist locks which engage releasably with corner castings of the bulk transportation containers.

The method may include securing the draught vehicle connection means releasably to the bulk transportation container.

The method may include securing the bulk transportation containers together by a plurality of connectors, each of which engages with adjacent corner castings of the bulk transportation containers and urges them towards one another.

According to another aspect of the invention there is provided a trailer which includes a load receiving body having a front and a rear; at least one wheel set secured releasably to the body at or towards the rear thereof; and draught vehicle connection means whereby the trailer is disconnectably connectable to a draught vehicle secured releasably to the body at or towards the front thereof, the body forming the load bearing structure of the trailer.

The body may be formed by at least one bulk transportation or shipping container.

According to still another aspect of the invention there is provided a trailer which includes a load receiving body having a front and a rear, the body being formed by at least one bulk transportation container;

at least one wheel set secured to the body at or towards the rear thereof; and draught vehicle connection means whereby the trailer is disconnectably connectable to a draught vehicle secured to the body at or towards the front thereof, the body forming the load bearing structure of the container.

The body may include at least two bulk transportation containers secured together end-to-end.

The draught vehicle connection means may be secured to one of the bulk transportation containers and the wheel set is secured to at least the other bulk transportation container.

The wheel set may be secured to both of the bulk transportation containers.

The wheel set may be secured to the or each bulk transportation container releasably making use of twist locks which engage releasably with corner castings of the bulk transportation containers.

The draught vehicle connection means may be secured releasably to the bulk transportation container.

The draught vehicle connection means may include a front sub-frame having a pair of transversely spaced twist locks which releasably engage bottom corner castings at a front of the body and a pair of tensile elements which extend between the front sub-frame and the top corner castings.

The bulk transportation containers may be secured together by a plurality of connectors, each of which engages with adjacent corner castings of the bulk transportation containers and urges them towards one another.

Each connector may include a pair of corner casting engaging fingers for releasably engaging corner castings of the bulk transportation containers and a shank which has oppositely disposed screw threads extending inwardly from opposed ends

thereof and screw threadedly engaging complementary threaded holes in the fingers such that rotation of the shank relative to the fingers in one direction urges the fingers towards one another and rotation of the shank relative to the fingers in the opposite direction urges the fingers apart.

The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings.

In the drawings, Figure 1 shows a side view of a trailer in accordance with the invention;

Figure 2 shows a side view of the trailer of Figure 1 connected to a draught vehicle;

Figure 3 shows a rear view of the trailer of Figure 1 and 2; Figure 4 shows an oblique view of part of the underside of the trailer; Figure 5 shows a side view of another trailer in accordance with the invention;

Figure 6 shows, on an enlarged scale, a lower connection between bulk transportation containers forming the body of the trailer of Figure 5;

Figure 7 shows, on an enlarged scale, an upper connection between the bulk transportation containers; and Figure 8 shows, on an enlarged scale, the connection of draught vehicle connection means to one of the bulk transportation containers.

In the drawings, reference numeral 10 refers generally to a trailer in accordance with the invention.

The trailer 10 includes a load receiving body in the form of a conventional bulk transportation or shipping container 12. The trailer 10 further includes a wheel set, generally indicated by reference numeral 14 attached to the container 12 and draught vehicle connection means generally indicated by reference numeral 16 attached to the container 12.

The container 12 is a conventional bulk transportation or shipping container which includes a rectangular base 18 comprising a pair of elongated side members 20 and a plurality of longitudinally spaced parallel transversely extending cross members

22 (Figure 4) connected to the side members 20. A rectangular floor (not shown) is mounted on the base 18. A pair of parallel side walls 26 extend upwardly from opposed sides of the base 18 and a pair of parallel end walls 28 extend upwardly from the ends of the floor 24. A top 30 is connected to the upper edges of the side walls and end walls 26, 28. A door 32 is provided in one of the end walls 28. Instead, the door could be provided in a side wall 26. Handling lugs or corner castings 34 are provided at each corner of the body.

The wheel set includes a sub-frame 36 comprising a pair of transversely spaced parallel beams 38 to which a plurality of longitudinally spaced transversely extending transverse connecting members 40 is connected. One or more axles, in the embodiment shown two axles, are connected to the sub-frame 36 by a suspension arrangement 44. The sub-frame 36 is secured to the base 18 by mechanical fasteners such as nuts and bolts and/or by welding.

The draft vehicle connection means 16 includes a fifth wheel support 46 attached to the underside of the base 18 adjacent an operatively leading or forward end thereof.

If desired, a landing leg set 48 is attached to the underside of the base 18 such that the landing legs protrude operatively downwardly therefrom.

In use, in order to manufacture the trailer 10, a new or used bulk transportation container 12 is inverted such that the base 18 is uppermost. The sub- frame 36, fifth wheel support 46 and landing legs 48 are then attached to the base 18, typically by welding and/or by making use of mechanical fasteners such as nuts and bolts.

Suitable wiring (not shown) and brake lines (not shown) can be attached to the base 18 and terminate in connectors which are disconnectably connectable to a draft vehicle in a conventional fashion.

If not already attached, wheels 50 can be mounted on the axles connected to the sub-frame 36 and the container 12 is inverted once again such that it rests on its wheels and the landing legs.

The trailer 10 can then be connected disconnectably to a draft vehicle 52 and used as a conventional load carrying trailer.

The bulk transportation container 12 is relatively strong and able to resist the torsional, bending and shock loads that the trailer is subjected to. In addition, the inventor believes that by using containers 12, which are readily available, it will be more cost effective than the cost associated with manufacturing a conventional chassis and a box body.

Reference is now made to Figures 5 to 8 of the drawings in which reference numeral 100 refers generally to another trailer in accordance with the invention and, unless otherwise indicated, the same reference numerals used above are used to designate similar parts.

In this embodiment of the invention, the trailer 100 includes a load receiving body in the form of two conventional bulk transportation or shipping containers 12 connected end-to-end.

In order to secure the containers together, use is made of four connectors, generally indicated by reference numeral 102. As can best be seen in Figure 6 of the drawings, each connector 102 includes a pair of corner casting engaging fingers 104 and a shank 106. The shank 106 has a left hand screw thread 108 extending longitudinally inwardly from one end thereof and a right hand screw thread 1 10 extending longitudinally inwardly from the other end thereof. Each of the fingers 104 has a screw threaded hole therethrough which threads are complementary to the screw threads 108, 1 10 such that rotation of the shank 106 relative to the fingers 104 in one direction urges the fingers 104 towards one another and rotation of the shank 106 in the opposite direction relative to the fingers 104 urges the fingers 104 apart. If desired, a locking nut 1 1 1 is mounted on one of the threaded portions of the shank 106 and is displaceable between a locked position (shown in Figure 6) in which it abuts tightly

against the associated finger 104 thereby to inhibit rotation of the shank relative to the fingers and a released position in it is clear of the associated finger and permits rotation of the shank relative to the fingers.

Further, in this embodiment of the invention, the wheel set 14 comprises four axles connected to the sub-frame 36 by suspension arrangements 44.

It will be appreciated, however, that the wheel set can comprise any desired number of axles.

The sub-frame has three pairs of twist locks 1 12, 1 14, 1 16. The pair of twist locks 1 12 releasably engages the rearmost corner casting 34 of the rear container 12.

The pair of twist locks 1 14 releasably engage the forward corner castings of the rear container 12 and the pair of twist locks 1 16 releasably engage the rear corner castings of the front container 12. Extending upwardly from the sub-frame 36 is a pair of transversely spaced apart spacer blocks 1 18 which are positioned between adjacent corner castings 34 of the two containers 12 and against opposite sides of which the corner castings are urged by means of the connectors 102.

Top spacer blocks 120 are positioned between the top corner castings. The blocks 120 are retained in position by oppositely disposed protrusions 122 which extend into the adjacent corner castings.

The draught vehicle connection means 16 includes a front sub-frame 124 having a pair of twist locks 126 which releasably engage with the front corner castings

34 of the front container 12. The front sub-frame further includes a pair of securing eyes 128 which protrude upwardly from the front sub-frame on opposite sides of the front container 12. A tensile element 130 is connected to and extends between each eye 128 and the top corner casting 34 to secure the front sub-frame 124 releasably in position. The tensile element 130 typically includes a length of chain 134 incorporating a chain tensioner 136.

In order to manufacture the trailer 100, the blocks 120 are positioned between adjacent top corners of the containers 12. The sub-frame 36 is positioned in abutment

with the operatively under surface of the rearmost container such that the blocks 1 18 are positioned between the adjacent corner castings 34 at the bottom of the adjacent containers. The sub-frame is secured to the containers by using the twist locks 1 12, 1 14, 1 16. The fingers 104 of the connectors 102 are then engaged with the corner castings and the shanks106 are rotated so as to draw the fingers 104 towards one another and thereby urge the adjacent ends of the containers 12 into abutment with the blocks 1 18, 120 which serves to secure the containers 12 together in a substantially rigid fashion.

The front sub-frame 124 which carries a part of the fifth wheel is then secured to the front container 12 making use of the twist locks 126 and the tensile elements 130. The trailer 100 can then be used in a conventional fashion.

In this embodiment of the invention, once again, the bulk transportation containers 12 form the load bearing structure of the trailer. However, by virtue of the fact that the sub-frames 36, 124 are disconnectably connected to the containers, the trailer 100 can be driven to a desired location, and instead of unloading the containers

12 and reloading them, they can simply be disconnected from the sub-frames 36, 124 which can then be connected to another pair of containers 12, in the manner described above, permitting a relatively quick turnaround time, thereby improving efficiency and decreasing the cost associates therewith.

Further, in respect of the trailers 10, 100, the sub-frame 36 which is used is considerably smaller and lighter than the chassis of the prior art trailers. This has the advantage that the centre of gravity of the trailer 10, 100 is lower when compared to prior art trailers leading to increased stability. Further, by virtual of the reduction of the weight of the trailer due to the elimination of the heavy chassis, the trailer is substantially lighter than prior art trailers. This naturally allows a trailer in accordance with the invention to transport a heavier load than the prior art whilst remaining within the maximum permitted axle load of the trailer.