Internally stiffened hollow plastics window frame - has internal stiffeners pushed into already constructed hollow outer frame

摘要

A closed frame, esp. for windows, is esp. of plastics and consists of a hollow section, inside which a further reinforcing frame is seated. The assembly is produced as follows. The outer, plastics, hollow closed frame (1) is first constructed, then openings (8, 10) are formed at its faces near the corners, then stiffening frame members (12) are pushed through these openings to seat in the voids of the frame, and then these stiffening members (12) are joined together at the corners to form a rigid stiffening frame. Finally, the openings (8,10) are closed. Pref., the stiffening or reinforcing components (12) are welded or sealed together at the corners to form the inner closed frame, or are bolted or screwed together. The openings may be sealed by plugs or caps welded or sealed in position. The method of construction is extremely simple, and eliminates complicated procedures for sealing or welding at mitred and similar joints.