Abstract: A lock includes a face plate into which a lock cylinder is mounted. Extending from the rear side of the face plate is a frame for supporting the back of the lock cylinder. A cover plate covers the front of the lock cylinder and includes one or more arms extending through the face plate to the back thereof, where the arms are secured against the plate. By this arrangement, the cover plate is secured to the back of the face plate, preventing removal of the lock cylinder by prying. The frame secures the lock cylinder to the rear, preventing it from being dislodged by hammer blows. Against all such attacks, the full structural integrity of the face plate serves to keep the lock cylinder in place and the lock secure.

Abstract: The present invention concerns an assembly for removably securing a real estate key box to a fixed structure, such as a door or wall. The assembly is designed so that when the key box is mounted on the assembly and locked, neither the key box nor the assembly can be removed from the structure.

Abstract: A lid is secured to the base of a key box device that defines an enclosed compartment for securing a spare key. The lid carries push-buttons and a knob for locking the lid to the base. The surface of the lid is generally flush with the plane of the base edges thereby eliminating locations for prying the lid from the base. A flanged portion in the lid and corresponding recessed portion in the base sidewalls provide gripping sidewalls to facilitate handling of the lid.