Abstract: A device for closing a cover onto a container, wherein the cover and the container each have a protruding flanged edge which come to lie against each other in the closing position and wherein a hook-shaped cam connected to the cover co-acts with a counter-cam connected to the container for the purpose of locking the cover onto the container, wherein both flanged edges have continuous slotted holes in a corresponding pattern, wherein a wedge-shaped hand-tool can be placed into two mutually registering holes in the flanged edges to turn the cover in relation to the container, such that the hook-shaped cam connected to the cover comes into engagement with the counter-cam, whereby with a simple tool all locks are placed simultaneously in or out of engagement during closing or release of the cover.