The invention concerns a trailer adapted for releasable connection with a truck or a similar vehicle. The trailer comprises a substantially planar loading surface and a housing being foldable between a retracted state, in which it is stored at one end of the trailer leaving the loading surface open, and an extended state, in which it extends from one end of the trailer to the other end of the trailer covering the loading surface. The trailer is further provided with a plurality of locks for locking engagement with corresponding locking means of a shipping con- tainer.

Description of related art

Trucks with trailer attached to them are commonly employed for shipping on land. The cargo is handled in essentially two different ways of transporting by trailer. The cargo can be loaded directly onto the floor or loading surface of a trailer, e.g. a flatbed trailer, where it may have to be secured to prevent it from moving during transport. It is also common to place pallets under the cargo to elevate it from the loading surface, which may be wet or dirty, and to enable an easy handling when loading and unloading. The trailers employed for transporting this kind of cargo usually have a housing providing protection of the cargo, as well as preventing cargo from falling off during transport. It is common that the housings have side curtains that can be folded back to enable loading from the sides of the trailer. In EP1356968 and EP1775160 it has even been proposed to have a retractable housing able to collect both of the side- walls and the roof at one end of the trailer, thereby enabling loading from both sides and from above.

The other way of handling cargo when transporting by trailer is to load it on the floor of a shipping container, which is subsequently placed on the trailer. The kind of trailers used for shipping container transport are usually skeletal trailers having no loading surface, however, shipping containers are also transported on flatbed trailers having a loading surface and no housing. It is required that the containers are secured to the trailers during transport. It is common that the shipping containers have standardized dimensions and standardized locking means, where 20 and 40 foot ISO containers used in intermodal freight trans- port are particularly common. For the case a flatbed trailers, it is known, e.g. from US 6,364,584, to secure the ISO containers by twist locks in the loading floor of the trailer.

In order to handle cargo in the two ways described, two types of trailers are needed, i.e. a flatbed trailer with a housing and a skeletal or flatbed trailer without a housing. This presents a problem in that the trailer may not be available that is compatible with a specific cargo, or oppositely, cargo may not be available that is compatible with a specific trailer. For example, a flatbed trailer without a housing delivers a shipping container at a first location. At this location, the closest cargo to be transported has not been loaded in a shipping container, but on pallets only. Hence, the flatbed trailer cannot carry this cargo and has to find containerized cargo further away, leading to an increased travelling distance for reloading, which in turn leads to higher over head costs in that the total fuel consumption, vehicle service cost, and driving time increase. Further, the increased travelling distance also has a negative impact on the environment. Alternatively, longer wait periods for cargo of the right type to be available at a particular loading site may be needed.

It is an object of the present invention to reduce unnecessary travel distances or to shorten wait periods in the transporting of cargo by trailers. An advantage of the present invention is that it reduces unnecessary fuel consumption, vehicle service cost, and driving time. The above object and advantage, together with numerous other objects and advantages, will be evident from the detailed descriptions given below of preferred embodiments according to the present in- vention.

The objects and advantages are according to a first aspect of the present invention obtained by a trailer adapted for releasable connection with a truck or a similar vehicle. The trailer comprises a substantially planar loading surface and a housing being foldable between a retracted state, in which it is stored at one end of the trailer leaving the loading surface open, and an extended state, in which it extends from one end of the trailer to the other end of the trailer cover- ing the loading surface. The trailer is further provided with a plurality of locks for locking engagement with corresponding locking means of a shipping container.

With the housing in its retracted state, a shipping container can be loaded onto the loading surface of the trailer and secured by engaging the locks, thereby allowing transport of shipping containers. With the housing in its extended state instead, the loading surface is within the housing, thereby allowing cargo to be loaded directly onto the floor of the loading surface. By this, both of the above- mentioned ways of handling cargo are possible with the disclosed trailer.

The housing may be retractable to such a degree that the combined length of a 40-foot shipping container and the housing in its retracted state does not exceed the length of the loading surface of the trailer. This means that the commonly used 40 foot ISO containers will fit onto the trailer. The housing may in its retracted state be collected at the front end of the trailer, which has the ad- vantage that the shipping container also can be loaded onto loading surface from the rear end of the trailer. The housing may define a longitudinal length in its retracted state that is equal to or less than 1.4 m. To be more precise, the housing may define a longitudinal length in its retracted state that is equal to or less than 1.32 m. This will enable the commonly used 40-foot ISO containers to fit onto the trailer.

The housing may comprise a tarpaulin roof, a first tarpaulin wall positioned at one side of the trailer, a second tarpaulin wall positioned at the other side of the trailer, and a plurality of support frames. This has the advantage that the hous- ing will be lightweight, thereby allowing for an easier handling when retracting or extending the housing. The support frames may be repositionable in the longitudinal direction of the trailer and defining an accordion bellow shape of the housing when the housing is in its retracted state. This has the advantage that the housing can be retracted by simply pushing its backside towards the front end of the trailer, or extended by simply pulling its backside towards the back end of the trailer, thereby allowing for an easier handling when converting the trailer.

The plurality of support frames may comprise a first vertical wall stud positioned at one side of the trailer and providing support for the first tarpaulin wall, and a second vertical wall stud positioned directly opposite of the first wall stud at the other side of the trailer and providing support for the second tarpaulin wall. The first vertical stud and the second vertical stud may be connected at their respective upper ends by a transverse joist providing support for the tarpaulin roof. The first vertical wall stud may be attached to a first longitudinal rail by a first sliding connection at the lower end of the first vertical wall stud, and the second vertical wall stud may be attached to a second longitudinal rail by a second sliding connection at the lower end of the second vertical wall stud. This has the advantage that it provides a stable housing that is simultaneously retractable and extendable. Two neighbouring support frames of the plurality of support frames may be joined at either side of the trailer by a linkage folding the tarpaulin wall on respective side over the loading surface when retracting the housing. This feature has the advantage that the housing will not extend significantly beyond the loading surface of the trailer when the housing is in its retracted state, which has the advantage that less of the housing will be in the way when handling a shipping container close to the trailer when loading or unloading. It also has the advantage of a reduced air resistance during trans- port in this state.

The housing may have a backside comprising a door frame attached to the first longitudinal rail and the second longitudinal rail, and one or more doors being pivotally supported by the doorframe. This feature has the advantage that cargo can be loaded directly onto the loading surface, even though the housing is in its extended state. The plurality of locks may be provided in the load floor of the trailer. This has the advantage that they will be reachable from the ground for manual engagement or disengagement, thereby simplifying the loading. Further, the plurality of locks may be retractable below the loading surface of the trailer, which has the advantage that cargo also can be placed at the positions of the locks. The plurality of locks may be positioned at the corners of the open loading surface outside the retracted housing of the trailer. This means that the locks are spaced as far away as possible on the loading surface, which optimizes the strength and stability of the securing of a shipping container to the trailer.

The plurality of locks may be twist locks positioned to engage the lower corner castings of two 20 foot shipping containers placed onto the trailer. This has the advantage that two standardized container can be loaded onto the loading surface by a quickly engageable and sturdy locks. Further, the plurality of locks may be twist locks positioned to engage the lower corner castings of a 40 foot shipping container placed onto the trailer, which has the advantage on of the most commonly used shipping container types can be loaded onto the loading surface by a quickly engageable and sturdy locks.

The objects and advantages are according to a second aspect of the present invention obtained by the use of a trailer according the first aspect of the present invention comprising:

a) the loading of the shipping container onto the loading surface of the trailer at a first location, the housing being in its retracted state, and the locking of the shipping container to the trailer by engaging the plurality of locks with the corresponding locking means on the shipping container,

b) the transporting of the trailer carrying the shipping container to a second lo- cation,

c) the unlocking of the shipping container from the trailer by disengaging the plurality of locks from the corresponding locking means on the shipping con- tainer and the unloading of the shipping container from the loading surface of the trailer at the second location,

d) the extending of the housing from one end of the trailer to the other end of the trailer covering the loading surface,

e) the loading of goods onto the loading surface, and

f) the retracting of the housing and the storing of the housing at one end of the trailer leaving the loading surface open.

This use has the advantage that it reduces unnecessary fuel consumption, vehicle service cost, and driving time when transporting both pallet cargo and shipping containers.

Brief description of the drawings

Additional objects, advantages and features will be readily apparent from the detailed description and drawings of a presently preferred embodiment of the present invention, where:

Figure 1 illustrates a side view of a trailer with its housing in its retracted state and having a 40 foot ISO container placed on its loading surface,

Figure 2 illustrates a side view of a trailer with its housing in its retracted state and having two 20 foot ISO containers placed on its loading surface,

Figure 3 illustrates a side view of an unloaded trailer with its housing in its retracted state,

Figure 4 illustrates a side view of an unloaded trailer with its housing in its extended state, and Figure 5 illustrates a top view of an unloaded trailer with its housing in its retracted state.

Detailed description of the invention

A trailer according to the presently performed embodiment of the invention is shown in Figure 1. The trailer 10 has a king pin or connection nipple 11 for being received in a quick release coupling device, or fifth wheel coupling, on a truck or towing vehicle. The trailer has a flat loading surface 16 and a foldable housing 12 being in its retracted state and stored at the front end 13 of the trailer 10. In the preferred embodiment, the foldable housing 12 has a tarpaulin roof and tarpaulin sidewalls held up by support frames 15. However, for the sake of clarity, the tarpaulins have not been depicted, but only the support frames 15. Further, the housing 12 has a door frame 21 supporting a double door 22 at its backside and a stationary wall 23 at its front side. A 40 foot ISO container 17, having locking means 18 in the form of corner castings, is placed on the loading surface 16 of the trailer 10. The trailer 10 is provided with locks 19 in the form of twist locks that are positioned so that they can be received in and engage to the locking means 18. The locks 19 are retractable below the loading surface 16 of the load floor 30.

The same trailer 10 as in Figure 1 is also depicted in Figure 2, but with two 20- foot containers 20 placed on its loading surface 16 instead. The 20 foot con- tainer 20 has locking means 28 of the same type as the previous 40 foot container and the same locks 19 are engaged for securing the two 20 foot containers 20. Additional locks 21 in the form of twist locks are provided to lock onto the unsecured ends of the 20-foot containers 20. These additional locks 21 are also retractable below the loading surface.

In Figure 3 the same trailer 10 as in Figure 2 is depicted, but with no container on its loading surface 16. Three measures a, b and c has been indicated, where the first measure a corresponds to the longitudinal length of the housing 12 in its retracted state, the second measure b corresponds to the length of the loading surface 16 being open when the housing 12 is in its retracted state, and the third measure c corresponds to the total length of the loading surface 16. Here, c is equal to the sum of a and b. In the presently preferred embodiment, the first measure a is equal to or less than 1.32 m, which, for a common commercial total length c of the load surface 16, gives a sufficient length of b the open loading surface 16 for it to carry the whole length of a 40 foot container.

In Figure 4 the same trailer 10 as in the previous figure is depicted, but with the locks removed and the foldable housing 12 being in its extended state, in which it extends from the front end 13 to the back end 14 of the trailer 10. As in the previous figures, the tarpaulins of the housing 12 have not been depicted for the sake of clarity, thereby revealing the support frames 15 underneath providing support for the tarpaulins. Each support frame 15 has a vertical wall stud 24 on either side of the trailer 10, which are connected transversally by a transverse joist 25. Two neighbouring support frames 15 are joined on either side of the trailer 10 by a linkage 29, which folds the tarpaulin walls on respective over the loading surface towards the longitudinal centre of the loading surface when retracting the housing, whereby the housing will define an accordion bellow shape. The vertical wall studs 24 are attached at their lower ends to longitudinal rails 26 on either side of the trailer 10 by sliding connections 27, allowing a longitudinal shifting of the positions of the support frames 15.

Figure 5 illustrates the top view of the trailer depicted in Figure 3, i.e. an unloaded trailer with its housing in its retracted state, which reveals the longitudinal rails 26 placed on either side of the trailer 10.

The same indexing for the same features or elements has been used in all of the figures. Item list

10 trailer

11 king pin 12 housing

13 front end

14 back end

15 support frame

16 loading surface 17 40-foot ISO container

18 locking mean 40-foot ISO container

19 20/40-foot lock

20 20-foot container

21 20-foot lock 21 door frame

22 double door

23 stationary wall

24 vertical wall stud

25 transverse joist 26 longitudinal rail

27 sliding connection

28 locking mean 20-foot ISO container

29 linkage

30 load floor