Locking the panels onto each other

The panels have two kinds of locking mechanisms. On is a rotating one, and the other is a fixed on.

Idea for the rotating one:

This kind of rotatory mechanism consist on a panel with a movable flange be able to retract a block system when pull from it.  The locking mechanism is componen of a cylindrical plastic piece with differents sections which serve to block with others panels and it's attached to movable flange through a cord. The retraction is possible thanks to a elastic spring joined to the plastic piece.