E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
E06B—FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES
E06B3/00—Window sashes, door leaves, or like elements for closing wall or like openings; Layout of fixed or moving closures, e.g. windows in wall or like openings; Features of rigidly-mounted outer frames relating to the mounting of wing frames
E06B3/04—Wing frames not characterised by the manner of movement
E06B3/06—Single frames
E06B3/08—Constructions depending on the use of specified materials
E06B3/12—Constructions depending on the use of specified materials of metal
E06B3/14—Constructions depending on the use of specified materials of metal of special cross-section
E06B3/16—Hollow frames of special construction, e.g. made of folded sheet metal or of two or more section parts connected together