[4] BACKGROUND OF THE INVENTION [5] In general, the wall of a building like as that of a factory, a warehouse or a house is constructed with concrete. However, it is often constructed with a plurality of lightweight panels such as sandwich panel, which are composed of a pair of skins made of steel or plaster board and an insulation embedded between the skins.

[6] However, there is a problem that double window cannot be mounted if the wall is constructed with lightweight panels whose thickness is about 50mm to 100mm. So to speak, if the thickness of the lightweight panels is about 50mm to 100mm and that of the window frame for the double window is about 200mm or more, the wall may be overloaded owing to the loads of the window frame and the window. Therefore, the window frame cannot be stably supported so that the windows cannot be mounted dually or more.

[7] SUMMARY OF THE INVENTION [8] The invention is created to solve the above described problems and so the object of the invention is to provide a window frame wherein window may be mounted dually or more although the thickness of a wall is relatively thin.

[9] According to an aspect of the invention, there is provided a window frame comprising a rectangular frame 33 which has a pair of vertical bais 10 and a pair of horizontal bais 20; [10] wherein the vertical and the horizontal bais 10,20 are composed of an inner frame portion 15 which is positioned inside the surface of a wall 1 and an outer frame portion 35 which is integrally formed with the inner frame portion 15 as one body and is positioned outside of the surface of the wall 1, a plurality of window rails 18 are formed at the inner surfaces of the inner and the outer frame portions 15,35, the window rails 18 of the outer frame portion 35 are positioned outside the surface of the wall 1, and a rectangular flange 55 is formed at the outer periphery of the rectangular frame 33 so that the rectangular flange 55 is contacted to the surface of the wall 1 and the rectangular frame 33 may be supported by the rectangular flange 55.

[11] According to another aspect of the invention, there is provided the window frame wherein a brace member 60 is connected between the outer frame portion 35 and the rectangular flange 55, and a plurality of ribs 70 are formed at the brace member 60.

[12] BRIEF DESCRIPTION OF THE DRAWINGS [13] Figure 1 is a dissembled perspective view of the invention.

[14] Figure 2 is a front view of the invention.

[15] Figure 3 is a A-A sectional view of Figure 2.

[16] Figure 4 is a B-B sectional view of Figure 2.

[17] Figure 5 and Figure 6 are respectively sectional views of another embodiment of the invention.

[18] DETAILED DESCRIPTION OF THE INVENTION [19] A preferred embodiment of the invention will be described in detail below by referring to the accompanying drawings.

[20] Figure 1 is a dissembled perspective view of the invention, Figure 2 is a front view of the invention, Figure 3 is a A-A sectional view of Figure 2, Figure 4 is a B-B sectional view of Figure 2, Figure 5 and Figure 6 are respectively sectional views of another embodiment of the invention.

[21] Referring to the drawings, the invention comprises a rectangular frame 33 which has a pair of vertical bais 10 and a pair of horizontal bais 20. Here, the vertical and the horizontal bais 10,20 are composed of an inner frame portion 15 and an outer frame portion 35, and a rectangular flange 55 is formed at the outer periphery of the rectangular frame 33.

[22] As shown in Figure 1, the horizontal bar 10 and the vertical bar 20 are made by extrusion molding so that the inner frame portion 15 and the outer frame portion 35 may be integrally molded as one body. They are molded with aluminum or synthetic resin. As shown in Figure 2, a pair of the vertical bais 10 and a pair of the horizontal bais 20 are connected in rectangular shape so that they form a rectangular frame 33.

[23] The inner frame portion 15 is positioned inside the surface of the wall 1 and its outer surface is contacted to the inner surface of the opening 2a of the wall 1. And, as shown in Figure 3 and Figure 4, a pair of window rails 18 are formed at the inner surface of the inner frame portion 15 along the vertical and the horizontal direction.

The inner window rails 18 face each other. The inner window rails 18 of the inner frame portion 15 are positioned inside the surface of the wall 1. And, a pair of two inner windows may be slid along the upper and the lower window rails 18 of the inner frame portion 15. And, the side ends of the two inner windows are respectively inserted into the right and the left window rails 18 of the inner frame portion 15 when the user closes the inner windows.

[24] The outer frame portion 35 is formed at the outdoor surface of the inner frame portion 15 as one body. And, a pair of window rails 18 are formed in the inner surface of the outer frame portion 35 along the vertical and the horizontal direction. The outer window rails 18 face each other. The outer frame portion 35 and the outer window rails 18 are positioned outside the surface of the wall 1. And, a pair of outer windows may be slid along the upper and the lower window rails 18 of the outer frame portion 35. And, the side ends of the two outer windows are respectively inserted into the right and the left window rails 18 of the outer frame portion 35 when the user closes the outer windows.

[25] Here, a rectangular flange 55 is formed at the outer periphery of the rectangular frame 33, and it is contacted to the surface of the wall 1. The rectangular flange 55 prevents the outer frame portion 15 from being detached toward the interior side of the wall 1. The rectangular flange 55 supports the rectangular frame 33. And, the flange 55 makes the loads of the rectangular frame 33 and the windows dispersed toward all directions.

[26] Further, a brace member 60 is connected between the outer frame portion 35 and the rectangular flange 55. And, ribs 70 are formed at the brace membeis 60.

[27] The brace member 60 also makes the loads of the window frame and the windows dispersed all directions so that the wall 1 may endure the loads of the windows and the rectangular frame 33.

[28] And, the ribs 70 makes the loads of the rectangular frame 33 and the windows dispersed all direction. Therefore, the loads of the rectangular frame 33 and that of the windows may be dispersed more effectively owing to the ribs 70 than the case that there is only the brace member 60.

[29] Therefore, although the thickness of the wall 1 is about 50mm to 100mm and that of the window frame is about 200mm or more, the loads of the rectangular frame 33 and the windows may be dispersed toward all directions so that the windows may be mounted at the wall 1 dually or more.

[30] Accordingly, the invention has a benefit that, although it is mounted at the relatively thin wall 1 whose thickness is about 50mm to 100mm, the loads of the rectangular frame 33 and the windows may be dispersed effectively so that the windows may be mounted dually or more. And, the invention has a benefit that the windows may be mounted dually or more without special equipment so that the work numbeis may be decreased and the cost like as construction expenses may be saved.

[31] Here, the reference number 93 of Figure 1, Figure 3 and Figure 4 is a supporting jaw. The supporting jaw 93 prevents the outer frame portion 35 from being detached toward the outdoor side of the wall 1.

[32] Further, as shown in Figure 5 and Figure 6, a pair of the outer frame portions 35 may be symmetrically formed at the outdoor surface and the indoor surface of the inner frame portion 15. According to Figure 5 and Figure 6, the symmetrical outer frame portions 20 are supported by a pair of rectangular flanges 55, and the outer frame portions 35 and the rectangular flanges 55 are connected by a pair of brace membeis 60. In case of Figure 5 and Figure 6, the loads of the rectangular frame 33 and the windows may be symmetrically dispersed all directions so that the loads may be dispersed much more effectively than Figure 1 to Figure 4. And, according to Figure 5 and Figure 6, one inner window and two symmetrical outer windows may be mounted so that the windows may be mounted triply. Accordingly, there is a benefit that the insulation effect and so on may be increased more than the case that the windows are mounted dually.