Abstract: A screen frame formed from a metal sheet in a single unit folds and locks on V-cuts in a tube by a locking mechanism that is configured to engage in crossed directions by the folding.

Abstract: A one-piece sealed, hollow, steel sliding screen door frame and method of fabrication thereof is described. A flat steel strip is diecut to produce 45.degree. miter cuts, each having an opposing flap. The cut strip is rolled to produce a frame stock having an essentially rectangular profile. Longitudinal edges of the strip are folded together, crimped and bonded during the rolling and form a screen channel in the frame stock. The frame stock is bent at right angles at the miter cuts such that the flaps tuck under the miter cuts, forming a rectangular door frame. Epoxy is used to bond the flaps to the inner surfaces adjacent the miter cuts. A screen door assembled using the door frame includes self-centering wheel assemblies.

Abstract: A screen or patio door adapted for sliding along a track in a doorway or other opening includes a generally rectangular frame of extruded aluminum channel having four generally L-shaped corners, at least two of the corners positioned along the bottom of the door and adapted to slide along the track. Each corner is formed by a 90.degree. miter cut leaving a web of aluminum material bridging the cut, and thereafter bending the channel about the web to form the corner. The corners all include a corner lock extending through the channel and bridging the miter, with fasteners extending through the channel. The fasteners extend through and expand the corner lock to fill the channel, thereby forming an inside wall bridging the miter cut and unitizing the corner construction.