Abstract: This device for closing an opening includes a frame (4) that delimits a pass-through access opening (10) suitable for receiving a cover (6) and which includes a frame hinge knuckle (18). The frame hinge knuckle (18) includes a hinge surface (38) and a pass-through hinge knuckle opening (40). The frame (4) has an exterior side and an interior side. The device also includes an inserted plug (52) positioned in a recess (50) of the frame hinge knuckle (18) located on the inner side of the hinge surface (38) and which makes the inner side of the frame hinge knuckle (18) appreciably sealed off from the outside.

Abstract: To endow such a device, of the type with a bolt (1) actuated by a key (2), with a high level of tamper-proofing and security without compromising its simplicity and reliability, the device includes two bolt-guiding members (3, 4) carried by one of the two elements, and the bolt includes a key-inserting aperture (114), two guiding ramps (112, 113) cooperating with the guiding members, and a third guiding ramp (115) cooperating with the key (2) when the latter is inserted into the aperture (114), in order to selectively actuate the bolt (1) from a locking position to an unlocking position, and vice versa, by rotation of the key. Use: devices for closing roadway or footway manholes, or underground technical chambers.