Patent ID: 7963436

Claim:
A cluster box mail delivery unit comprising: an enclosure comprising two sidewalls, a top wall, a bottom wall, a front face, and a back face; a rectangular door frame mounted to the front of the enclosure having a first vertical side and a second vertical side, with the first vertical side having a first frame hinge structure along the entire first vertical side formed with an interfitting upright extrusion having a complexly curved groove; a first door assembly mounted on the front face of the enclosure having a inner edge and an outer edge, with the outer edge forming a first door hinge structure along the entire outer edge that includes a curved formation capable of extending into the complexly curved groove of the first frame hinge structure when mounted on the enclosure, wherein: when the first door assembly rotates to a closed position, the complexly curved groove of the first frame hinge structure is inaccessible via a portion of the upright extrusion of the frame hinge structure overlapping a portion of the curved formation of door hinge structure on an outside of the first door assembly; and when the first door assembly rotates to a completely open position, the curved formation completely fills the complexly curved groove; and at least one compartment door within the first door assembly.