The AL00816 is a European designed weld on 3 piece hinge designed for use on the drop sides of farm trailers.
A common hinge pin / rail (Not supplied by Aline) connect the hinges. The flat centre section of the hinge is welded to this rail and when the rail is rotated it opens the hinge allowing the drop side to be removed.
PRODUCT PHOTOS
The photo below shows a 3 piece hinge in use on a drop side trailer. The upper section is galvanised with the drop sideYou can see how a common rail is used to lock the keepers in place. This rail can be used to connect several hinges. When the rail is rotated it opens the hinges allowing for the drop sides to be removed.