A mechanical locking device at the corner of a container. Conventional twistlocks are locked and unlocked manually with operating rods. Rotating the movable part around a vertical axis locks the device and a container to a twistlock foundation on a hatch cover or another container. Reversing the motion effects unlocking. Semi-automatic twistlocks are locked automatically and unlocked manually by the operating rods. Fully-automatic locks are placed in the lower corners of the container at the pier. They lock automatically after the container is placed on the top, and unlock automatically when the container is lifted.
SAT CV-20 is fully symmetrical semi-automatic twistlock developed by MacGREGOR. When containers are loaded at a fast rate, incorect insertion of twistlock will cause major danger and delays in the cargo handling process. The CV-20 twistlock can be inserted into the container corner castings either way-up – incorrect insertion is not possible.