Low heat transmission framing rail structure, particularly door or window framing

Low heat transmission framing rail combination structure, particularly to form aluminum window or door framing elements, for cooperation with a window or door counter element (2)

• comprising, in accordance with the invention,
• three separate elongated, parallel-oriented metal rails (6, 7, 8) forming a first, outer metal rail (6), a second intermediate metal rail (7), and a third, inner rail (8);
• a first insulating material connecting strip (9) secured to the outer rail (6) and to the side of the second, intermediate rail (7) facing the outer rail, and structurally connecting said first, outer and second, intermediate rails together and forming an assembly;
• a second insulating material connecting strip (10) secured to the other side of the second, intermediate rail (7) and to the facing side of the third, inner rail (8), and structurally connecting said assembly of the first (6) and the second (7) rails and the first strip (9) to the third rail (8),
• the connecting strips (9, 10) extending outwardly from opposite sides of said second, intermediate strip (7), offset with respect to each other along the width of the rail so as to be out-of-alignment with respect to each other to prevent direct heat transmission between said strips through the intermediate rail (7) and forming continuous structural connection strips between said intermediate metal rail (7) and the first, outer metal rail and the third, inner metal rail (8), respectively, while inhibiting metal-to-metal heat transfer between said rails,
• and projecting rail strips (36, 37, 40) extending from said separate rails (6, 7, 8) to form, with the window or door counter element, two air chambers (12, 14) separated from each other by the projecting rail strip (37) from the intermediate or second rail (7) and by said two connecting insulating strips (9, 10).