FIELD OF THE INVENTION

This invention relates to open sided containers and in particular doors installed on the container sides.

Container transportation of goods provides an easy method of goods handling for transportation by road, rail and sea. An important aspect of the use of containerised transportation is the means by which the containers are loaded. The strongest form of container has openings at one or either end of the container. However, this does not enable efficient loading or unloading of the container.

In order to overcome this problem, open sided containers allow access to either side of the container over the length of the container.

A number of different closures for the sides of the containers are used. These include curtain side containers and hinged steel doors. Each of these methods come with several advantages and disadvantages.

In the case of curtain side closures, the container is much lighter which improves the ratio of load weight to all up weight.

However, opening curtain side containers is reasonably time consuming. Obviously, the curtains used with these containers are not able to resist any side loading through movement of the goods within the container and therefore a series of fence panels are installed along the side of the container to act as barriers for retaining the cargo. The curtain walls are then pulled in front of these barriers. In order to open the container, these barriers need to be individually removed. In addition to the time taken to open the container, the barriers reduce the internal space within the container.

The curtain side containers do not provide good security for the container and obviously can be easily accessed if the curtain wall is cut. Also, if the curtain is damaged or cut then it is difficult to repair and its lack of durability means replacement within a reasonably short period of time. In order to overcome some of the disadvantages of the use of curtains with open sided containers, these containers are known to use hinged steel doors. The hinged steel doors overcome the problem of security and load retention and obviously improve the amount of floor space within the container. However, the steel doors add to the weight of the container and therefore there is limited advantage in relation to the ratio of the load to all up weight. Also the steel doors are difficult to repair when maintenance is required. SUMMARY OF THE INVENTION

In one aspect, the invention is a door panel comprising a container having at least one open side portion and a plastic door for closing the open side portion that is moveable between an open and closed position. The provision of a plastic door provides increased security and the improved floor space within the container by comparison to curtain side containers without the increased weight which associated with steel doors.

Preferably, the plastic doors are bi-fold doors where one door panel is hinged to a second door panel with the second door panel being hinged with respect to the container. The door panels may be provided with latches which secure the door panel with respect to the container when in a closed position. The latches may be easily operated to release them and thereby allow opening of the doors

The plastic doors may be a solid plastic material or may comprise a hollow section or a hollow section that is filled with foam. Conventional manufacturing techniques for the door may comprise injection moulding or roto-form moulding techniques.

Preferably, the door panels are moulded so as to provide a number of recesses within which hinge plates may be located. The doors may also be moulded with metal fixtures having apertures or threaded apertures to enable various components to be secured to the door.

One problem with the use of plastic material is the possibility of the door having sufficient flexibility to result in the far end of the door sagging sufficiently to prevent the door being easily closed. This is particularly the case with a bi-fold door where there is a significant cantilever load from the side hinged to the container. In order to address this, the side of the door or doors furtherest from the container hinges may be supported with respect to the container to both allow opening of the door or doors while at the same time supporting the doors to limit sagging as they are opened and while they are open. The support may comprise a link or arm that is pivotally attached to both the free end of the door and the container and that moves either with respect to the container or with the door to support that end to limit dropping or sagging of the door. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

A preferred embodiment will now be described, however it will be realised that the invention is not to be confined or restricted to the scope described in this preferred embodiments. Alternatives that are apparent to a skilled person are considered to be within the scope of this invention.

This embodiment is illustrated in the accompanying drawings in which:

Figure 1 shows a plan view of a plastic door with latch and hinge fittings,

Figure 2 shows a cross section view about line 2-2 shown in Figure 1 ,

Figures 3, 4 and 5 show an open sided container with closed and open bi-fold doors and doors in various positions as they are being opened,

Figure 6 shows detail of the upper portion of latches used for the door,

Figure 7 shows detail of the latches at the lower edge,

Figure 8 shows an alternative hinge configuration,

Figures 9 to 12 show an arm used to support the bi-fold door assembly, and,

Figure 13 shows a single latch in plan view.

DETAILED DESCRIPTION OF THE INVENTION

The door panel 10 shown in Figures 1 and 3 comprises one panel of a bi-fold door. The door panel 10 comprises a moulded plastic panel 1 1 having a number of hinges 13 attached down each edge of the plastic panel 1 1.

The door panel 10 includes latches 14 which comprise a latch rod 15 that is rotatably mounted to the plastic panel 1 1 by saddles 16. Each end of the latch rod 1 S has a hook 17 for latching engagement with a container at either end, and a handle 30 for manually rotating each latch rod 15.

The door panel 10 is symmetric about its centre line so that the door panel 10 can be hinged on either or both vertical edges. The hinges 13 shown on the left side of the door panel 10 have a plate 19 that is secured to the plastic panel 1 1 by threaded fasteners. Each plate 19 locates within a recess moulded into the surface of the plastic panel 1 1. The hinges 13 on the left side of the door engage with pivot pins mounted to the container. The hinges located on the right hand side of the door panel 10 also have plates 19' that locate within moulded recesses within the plastic panel 1 1 but have pivotally mounted to the surface of the pjate 19' a hinge member having a second plate 20 which mounts to an adjoining plastic panel 12 of an adjacent door. This forms a bi-fold door as seen in Figures 3 to 5.

Figure 1 shows a different spacing of hinges 13 and 20 by comparison to Figures 3 to 5. In Figure 1 the upper and lower pairs of hinges 13 and 20 are more closely spaced to provide better strength to be able to resist high loads. Figures 3 to 5 show even spacing of the hinges 13 and 20.

The plastic panels 1 1 and adjoining panel 12 are moulded using a roto-form moulding technique. This produces a hollow panel section which may also be foam filled to produce an extremely rigid yet lightweight panel 1 1, 12.

As seen in Figures 3 to 5, one edge of the plastic panel 11 is hingedly mounted via the hinges 13 to a container 21. The two panels 1 1 and 12 are shown in a closed position in Figure 3 with the latches 14 engaged. A second pair of panels 1 1 and 12 are shown partly opened in Figure 3 and hinged to a centre column 25 of the container 21. As can been seen from the drawings, four sets of bi-fold doors are required to close one side of the container 21.

As can be seen in Figure 2, metal inserts 26 can be moulded or placed into the plastic panels 11 and 12 to enable fittings such as the saddles 16 and plates 19 and 19' to be secured to the panels 1 1 and 12. These metal inserts 26 are tubular which enable threaded fasteners (nut and bolt) to be used to secure the fittings such as the saddles 16 and hinges 13 without squeezing the panels 1 1 and 12. The metal inserts 26 can be inserted into moulds prior to forming the outer skin of the plastic panel 1 1. The metal inserts 26 provide the required strength for securing the fittings such as the saddles 16 and hinges plates 19 and 19'.

Figure 8 shows an alternative arrangement for the centre hinges 20 between the door panels 1 1 and 12. In this arrangement the hinges 20 are placed on the inside surface of the panels 1 1 and 12. Both axes of the hinges 20 are pivotally attached to the hinge plate 13 at a position that is spaced from the edge of each respective panel 1 1 and 12. This arrangement allows greater precision when closing the doors to allow accurate alignment of seals between each edge.

Figures 9 to 12 show a support that supports the door assembly to limit dropping or sagging of the doors as they are being opened and while they are in their open position. The support comprises an arm 40 which is, at one end, pivotally attached to a plate 42 that is itself secured to a panel 12. The other end of the arm 40 is pivotally attached to a wheeled dolly 43 where the dolly 43 is mounted in a track member 44. This assembly allows the doors to be fully opened while at the same time supporting the far end of the bi-fold doors to thereby limit the extent to which the door can drop or sag. As seen in Figure 10 the track member has mounted within it a sprung stop 46 against which the dolly 43 abuts as the panel 12 is about to close. This causes the arm 40 to rotate towards the door so that it is in the right position and orientation as the panel 12 closes. The panel 12 could not close if the arm 40 remains in the position shown in Figure 10. Also, as shown in Figure 12 the arm 40 has a bend or offset that will allow the doors to move to a fully open position.

Referring to Figure 13, each latch 14 engages a pin 50 in its closed position. The latch 14 is rotated by the latch rod 15 so that the hook 17 can be put into engagement with the pin 50 as shown in Figure 13. It can also be rotated sufficiently so that the hook 17 is clear of the pin 50 so that the latch 14 is released.

The amount of rotation of the latch 14 is limited by the handles 30 that rotate the latch rod 15. The handles 30 locate against the door panel 11 and 12 which brings the latch 14 to the position shown in figure 15. In this embodiment, in this position the hook 17 of the latch 14 is shaped to leave a clearance between the inside surface 52 of the hook 17 and the pin 50. This deliberate clearance means that tolerances of manufacture of the latch 14 can be larger and there is no likelihood of the inside surface 52 coming into contact with the pin 50 thereby removing the risk of wear to the latch 14 and pin 50.

As can be seen from the above description, the open side container using the door panels 10 as described above will result in weight saving by comparison to steel doors yet providing all the advantages of security and increased floor size by comparison to curtain side open containers.

Unlike steel doors, the open sided containers using plastic panels 1 1 and 12 can be easily repaired by simply replacing the damaged panel 1 1 and 12. As the panels 1 1 and 12 are manufactured from plastic, they can be easily recycled.

Also, because of the light weight nature of the door panels 11 and 12, then there is less stress applied to the hinges when the doors are opened. The cantilever forces applied to the hinges are minimised due to the lighter weight of the door panels 10.

A standard weight container using steel doors can weigh as much as 9 tonnes. However, a container using doors in accordance with this invention can reduce its weight to 6.5 tonnes. The difference in weight between the two containers can obviously be translated to increased load capacity for the container.