Abstract: Horizontal hinged door assemblies such as sidewalk doors comprising a door, a frame surrounding the door and a hinge connecting the door to the frame are improved by utilizing an anchor device which is inserted into an opening in at least one of the frame walls forming an outwardly extending flange for securing the door assembly to the structure forming the opening to be covered. The anchor device may be inserted into the frame during fabrication of the door assembly or on-site during installation of the door assembly. A variety of elongated shaped anchor devices may be used depending on the type door assembly installation. The anchor devices are preferably bendable to conform the anchor device to the site to which the door is being secured.