Locking device for use with stackable shipping containers

1. Technical Field of the Invention The invention is directed to a locking device which can be engaged in a conventional ISO aperture of a corner casting of an upper and lower shipping container stacked on a carrier to lock the containers together. The locking device has a housing having a compression pad with an upper and lower shear block. A spring-biased twist-head is engaged to the upper shear lock, and a spring-biased hook is engaged in the housing. When the upper and lower shear block of the lock are respectively engaged in the ISO aperture of the upper and lower corner castings of the stacked containers and the twist-lock and the hook are each in a closed position within the corner casting, relative movement between the containers is limited.