Fiberglass doors are common substitutes for traditional wooden doors in residential and commercial buildings. Fiberglass doors include door skins (also known in the art as door facings) secured to opposite sides of a rectangular door frame. A resulting cavity between the door skins and surrounded by the door frame optionally is filled with a core material, such as an expanded polymer foam. Doors so constructed can have wood graining printed, molded, or otherwise applied on the exterior surfaces of the door skins, and also raised paneling formed (e.g., molded) in the door skins. These features give the doors the appearance of natural wood fabricated products. Optionally, paint, stain, lacquer, and/or a protective layer may be applied to the exterior surface.
Fiberglass doors are a type of synthetic door. Fiberglass door skins are sometimes formed of sheet molding compound (or SMC) sheets containing resinous sheets reinforced with fiberglass, often chopped fiberglass or fiberglass mats. The sheet molding compound is deposited in a compression molding machine and subjected to high pressures and elevated temperatures to cure the resinous material and form the resulting door skins, which then are removed from the compression molding machine as a structurally stable, consolidated articles that may be secured to door frames.
Fiberglass doors sometimes include glazed units, also known as glazings, glass inserts, lights, or lites. A full size glazed unit may constitute a majority, even 60 percent or more, of the exterior surface area of a door. Other glazed units may be smaller. A window frame, typically made of plastic or a metal such as aluminum, surrounds the glazed unit and connects the door skins to the glazed unit. An example of a fiberglass door with a window frame connecting door skins to a translucent window is shown in U.S. Pat. Pub. No. 2008/0245003. As best shown in FIG. 3 of the published application, the window frame includes frame members 30, 50 surrounding the window. The frame members 30, 50 include bulbous door receiving portions 31, 51 and panel support portions 32, 52 with convex exterior surfaces extending outwardly from the planar areas of the door skins. Because of the bulbuous portions, stacking of multiple doors or door skins on one another for transport or storage is difficult and the stacks may be unstable because the bulbuous portions decrease surface contact area between stacked doors or door skins. Sliding and rocking of stacked doors/door skins can result in damage, such as paint picking, burnishing, and cracking to the exterior surfaces of the door skins.
USPTO Backgrounds
USPTO Backgrounds