Development of Electromagnetic Unlocking on Container Semi-Automatic Twistlocks

Semi-automatic twistlocks are devices used to secure containers together in a stack on container ships.They are a mainstay of container shipping because they are inexpensive, safe, and reliable. To unlock one, an operator is needed to manually open the lock, a process which can be slow and dangerous. Ideas for the new design were compiled into four (4) main concepts. After grading concepts through a selection matrix, and consultations with the client, a new concept based on a ratchet and pawl mechanism and designed to be opened by an electromagnet, was down-selected for development and prototyping. The reliability of the mechanism will be tested by putting it under a repeatability test. Using a test setup, comprising a standard cargo container with corner castings welded on, the developed twistlock will be continuously locked and unlocked.