Hinge assembly for the frame structure is provided. The hinge assembly includes an inner surface, an outer surface, and a bolt receiving bore extending therethrough, a first substantially flat plate. Bolt receiving bore extends along an acute angle bore axis with respect to the outer surface between the inner and outer surfaces. The second substantially flat plate, having an inner surface, and an outer surface, the bolt receiving bore through the interior. Bolt-receiving bore of the second plate extends along the sharp bore axis with respect to the outer surface between its inner surface and an outer surface. Pin pivotally connecting the first plate to the second plate. The first lip extends from the inner surface of the first plate, the second lip extends from the inner surface of the second plate.