This invention relates to means for securing freight containers together and more particularly to such means for co-operating with the corner fittings of standard containers.
Freight containers are produced in a series of standard sizes and are known as I.S.O. containers. These containers are provided with corner fittings each of which comprises a hollow, generally box-shaped component provided with apertures in some of the faces thereof for receiving therein releasable securing means. Hereinafter any reference to `corner fitting` is to be understood as referring to a corner fitting of the above described type.
It is conventional practice to transport large numbers of such containers on board ships with adjacent containers interconnected with one another to form a block of containers.
The current system for interconnecting adjacent containers is to utilize a pair of releasable securing means, commonly known as twistlocks, one located in one corner fitting of one container and the other located in the adjacent corner fitting of the other container. The two twistlocks are themselves interconnected by a screw-threaded bolt and associated nuts, which are screwed up to effect the necessary connection.
Such an arrangement has a number of disadvantages. The two twistlocks, together with the interconnecting bolt and nuts, are expensive to produce and are prone to corrosion, particularly at the nuts. Further, the twistlocks project outwardly from the end faces of the containers, while the screw-threaded bolts and nuts are located externally of the containers whereby said components are prone to damage and adjacent rows of containers must be spaced from one another to accommodate the connecting means.