GB2271375A - Locking arrangement for container doors - Google Patents

Abstract

A looking assembly for securing shut the door of a container comprises an elongate locking rod 2 mounted vertically in a channel provided in the external surface of the door 1. The locking rod 2 is rotatable about its longitudinal axis and has a cammed engagement head 11 at each end. Locking members 15 are supported by the container to engage and releasably secure the locking rod engagement heads 11. The door 1 is provided with apertures 8 through which the locking members 15 protrude when the door 1 is closed. A seal 9 is fixed to the inner surface of the door 1 around each aperture 8 and bears against the body of the container 12 to prevent water ingress through the apertures 8 when the door 1 is locked shut. <IMAGE>

Description

A LOCKING ASSEMBLY FOR SECURING SHUT THE DOOR OF A CONTAINER The present invention relates to a locking assembly for securing shut the door of a container, for example a freight container.

Goods are often transported in large cuboidal freight containers which can be loaded directly onto trains ships e.t.c. Such containers are built with predetermined external dimensions set by I.S.O.

standards. Access to the containers is generally through large hinged doors located in one end of the container. For strength the container doors are generally fabricated from corrugated sheet steel, as are the side walls of the container.

For safety reasons it is essential that the doors can be securely locked shut during transportation of the containers. For example, if the cargo in the container shifts in transport the doors may be subjected to a considerable load. Under existing regulations the locked doors must be able to withstand up to 0.6 of the maximum load of the container.

The usual locking assembly for container doors comprises locking rods which are mounted vertically on the external surface of the door and extend beyond the top and bottom edges of the door. The locking rods are mounted such that they can be rotated about their axis by the manual operation of an appropriately provided handle. The ends of the locking rods have cammed engagement heads which cooperate with "keepers" secured to the external surface of the container frame at appropriate positions above and below the door. Closing the door with the locking rods in an "open" position locates the cammed heads in the keepers. As the door closes, rotation of the locking rods by operation of the handle to a "closed" position securely inter-engages the cammed heads with the respective keepers and draws the door tightly shut.A lip-type seal is usually provided between the door and the container to prevent the ingress of water into the container.

Once in the closed position the operating handle can be locked to the container door to prevent accidental and unauthorised opening.

Such a locking arrangement is effective and is relatively cheap and easy to manufacture and assemble. However, as mentioned above the maximum external dimensions of freight containers are governed by I.S.O. regulations. The space occupied by the locking gear which is mounted on the outside face of the container door reduces the internal dimensions of the container. Thus the maximum usable length of the container is reduced by the presence of the externally mounted locking gear, with a corresponding reduction in the capacity of the container.

Structures have been proposed which overcome this disadvantage by mounting the locking rods within the thickness of the door. One such structure is disclosed in UK patent application No.2213134 A.

The locking rods are mounted vertically on the internal surface of the door within the overall thickness of the door. The ends of the locking rods fall short of the top and bottom edges of the door and have modified cammed locking heads. Corresponding keepers are supported by the container frame, internally of the door. The external surface of the door has a box-like recess through which the locking rods pass. That portion of each locking rod which passes through the recess and thus is accessible from the external surface of the door is provided with an operating handle. Seals are provided between the locking rods and the door where the rods enter and leave the recess.

This arrangement has several associated disadvantages. Firstly assembly of the door and locking gear to the container is relatively difficult as the cammed heads and keepers are not visible or accessible from outside the container when the door is shut. This makes difficult the task of accurately aligning the locking rods with the keepers. This increases assembly and maintenance time with a corresponding increase in cost.

Secondly, the seals between the locking rods and the door, which must enable rotation of the locking rods, are not always completely effective, especially after prolonged use. As a result water can enter the container between the seals and the locking rods resulting in damage to the contents of the container.

It is an object of the present invention to provide a locking assembly for a container door which obviates or mitigates the above disadvantages.

According to the present invention there is provided a locking assembly for securing shut the door of a container, comprising an elongate locking rod mounted on the external surface of the door, and a locking member supported by the container and adapted to releasibly engage the locking rod to secure the door shut, wherein the locking member protrudes through an aperture in the door when the door is closed.

Thus, the locking gear can be accommodated within the thickness of the door and this does not add to the overall length of the container. In addition, assembly of the door to the container frame is readily achieved as both the locking rod and the locking member supported by the container are accessible from the external surface of the door when the door is shut. It is possible to use a conventional seal around the periphery of the door. The locking rods can be secured in place either by welding or bolting.

Preferably the locking rod is mounted in a channel provided in the external surface of the door.

Preferably a seal is provided between the aperture in the door and the container to prevent water entering the container between the locking member and the door. Since the components contacted by the seal are stationary when the door is closed, a good water tight seal can be formed. The seal may be of any convenient type, for instance a closed cell neoprene seal may be used.

Preferably the seal is mounted on the door around the aperture in the door. Alternatively the seal may be mounted on the container around the locking member.

Preferably the locking rod is mounted on the door so that it can rotate about its longitudinal axis, at least one end of the locking rod having a cammed engagement head which is adapted to cooperate with the locking member, whereby rotation of the locking rod from a first to a second position when the door is closed securely interengages the cammed head with the locking member and rotation from the second to the first position releases the cammed head from the locking member.

Thus standard, industry accepted, locking heads and keepers may be incorporated in the locking assembly.

Preferably the locking rod extends vertically along the surface of the door, each end of the locking member engaging with an appropriately positioned locking member.

A specific embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which; Figure 1 is a front view of a container door in accordance with the present invention with locking rods removed; Figure 2 is a section of a container door in accordance with the present invention with locking rods in place; Figures 3 and 4 show components of a seal fixed to the door of Figure 1; Figure 5 is a front view of a container body in accordance with the present invention with the doors removed; Figures 6 and 7 are sections through Figure 5; Figures 8 and 9 are sections through part of the container of Figure 5 with the door of Figure 1 assembled thereto, illustrating the manner in which the door is sealed with respect to the container body; and Figure 10 is a section of part of a fully assembled container with the doors locked shut showing the locking gear.

Referring to the drawings, Figure 1 shows the external surface of a pair of container doors 1. A single door 1 is shown in crosssection in Fig. 2 which further shows locking rods 2 mounted to the external surface of the door 1. The broken lines 3 in Fig. 1 illustrate the positions occupied by the locking rods 2 when they are mounted to the doors 1.

Referring to Figures 1 and 2, each door is fabricated from 3mm thick sheet steel supported within a frame 4. Each door has a corrugated portion 5 and a vertically extending channel 6. Each channel 6 is of sufficient width to accommodate two locking rods 2 mounted vertically and side by side to the external surface of the door 1. The depth of the channel 6 is no greater than that of the door frame 4 and thus the channel 6 does not add to the overall thickness of the door 1.

Locking rods 2 are mounted to the external surface of the doors by means of brackets 7 such that the locking rods 2 may rotate about their longitudinal axes. The brackets 7 are welded to the external surface of the door 1, but it will be appreciated that they could be bolted to the door or affixed in any other suitable manner. Each locking rod terminates short of the top and bottom edges of the door 1 and has a standard cammed engagement head 11 at each end (see Fig.

10). Rectangular apertures 8 are provided in each door 1 at the location of the engagement heads of each locking rod.

A closed cell neoprene seal 9, supported within a rectangular channelled support member 10, is affixed to the inner surface of each door around the location of each aperture 8. The seal components are shown in detail in Figures 3 and 4. The seals 9 are secured to the surface of the doors 1 by welding the channel member 10 to the surface of the door 1.

The open end of a container body 12, to which the doors 1 are to be assembled, is shown in Fig. 5. The container body 12 isfabricated from corrugated sheet steel panels supported by a frame 13.

Cross-sections through the top and bottom of the mouth of the container 12 and through one side are shown in Figs. 6 and 7 respectively.

Five hinges 14 are fixed to each vertical side of the frame 13 for mounting the doors 1 to the container body 12. To mount the doors 1 the external surfaces of the hinges 14 are secured to the external surface of the doors 1.

Fixed to the container frame 13 at positions corresponding to the positions of the apertures 8 in the doors 1 are standard "keepers" 15 adapted to engage the cammed locking heads 11 of the locking rods 2. From Fig. 6 it can be seen that the keepers 15 are mounted on raised support blocks 16. Horizontal and vertical frame members 17 and 18 respectively provide sealing surfaces.

Figs. 8 and 9 are sections with a door 1 in place illustrating the manner in which the edge of the doors 1 are sealed with respect to the container frame 13. Resilient lip seals 19 which are secured to the frame 4 of each door 1 bear against the sealing surfaces provided by frame members 17 and 18. A good water tight seal is thus formed between the edges of each door 1 and the container body 12.

Referring now to Figure 10, it can be seen that when a door 1 is closed the keepers 15 project through the apertures 8 in the door 1 and into the channel 6. Thus the keepers 15 and cammed engagement head 11 can cooperate in the normal way. The seals 9 which surround the apertures 8 bear against the container frame 13 preventing water from entering the container through the apertures 8. It will be appreciated that once the seal is formed between the seal 9 and the container frame 13 there is no movement between the two and thus a good watertight seal is achieved. It will be understood that there are other forms of seal which could be alternatively employed.

The present invention thus maximises the usable capacity of a container by building the locking rods 2 within the thickness of the doors 1, thereby reducing the difference between the external and internal dimensions of the container. By providing the doors 1 with apertures 8 through which the keepers 15 can project, the locking gear will not interfere with the seals 19 provided around the edge of the doors 1. Furthermore, standard, industry accepted seals, keepers and locking heads can be employed. Sealing of the aperture 8 with respect to the container frame 13 is readily achieved with no moving parts to reduce the integrity of the seal once formed. All components of the locking assembly are visible and accessible from the external surface of the door which provides for ease of manufacture and maintenance.

Claims (12)

1. A locking assembly for securing shut the door of a container, comprising an elongate locking rod mounted on the external surface of the door, and a locking member supported by the container and adapted to releasably engage the locking rod to secure the door shut, wherein the locking member protrudes through an aperture in the door when the door is closed.

2. A locking assembly according to claim 1, wherein the locking rod is mounted within a channel provided within the external surface of the door.

3. A locking assembly according to claim 1 or 2, wherein a seal is provided between the aperture in the door and the container to prevent water entering the container between the locking member and the door.

4. A locking assembly according to claim 3, wherein the seal is a closed cell neoprene compression seal.

5. A locking assembly according to claim 3 or claim 4, wherein the seal is mounted on the door around the aperture in the door.

6. A locking assembly according to claim 3 or claim 4, wherein the seal is mounted on the container around the locking member.

7. A locking assembly according to any preceding claim, wherein the locking rod is mounted on the door so that it can rotate about its longitudinal axis, at least one end of the locking rod having a cammed engagement head which is adapted to cooperate with the locking member, whereby rotation of the locking rod from a first to a second position when the door is closed securely inter-engages the cammed head with the locking member and rotation from the second to the first position releases the cammed head from the locking member.

8. A locking assembly according to any preceding claim, wherein the locking rod extends vertically along the surface of the door, each end of the locking rod engaging with an appropriately positioned locking member.

9. A locking assembly according to any preceding claim, wherein the door is fabricated from corrugated sheet steel.

10. A locking assembly substantially as hereinbefore described with reference to the accompanying drawings.

11. A container door substantially as hereinbefore described with reference to the accompanying drawings.

12. A container substantially as hereinbefore described with reference to the accompanying drawings.