Windows and doors assembly structure having a joint portion of 45 degrees

A prefabricated window/door structure with interconnecting 45 degree joints wherein a pair of vertical bars and a pair of horizontal bars each connected to upper ends and lower ends of the vertical bars form a window/door frame holding a pane of glass or security window/door and a joint of the vertical bar and the horizontal bar forms an angle of 45 degrees, the window/door structure comprising:

• a pair of horizontal bars (20),
• a pair of vertical bars (30),
• a reinforcing piece (60) to be inserted in the joint of the horizontal bar (20) and the vertical bar (30), to reinforce and prevent warping of the joint, and
• a joint screw (40) to be fastened to the joint of the horizontal bar (20) and the vertical bar (30),
• wherein the horizontal bar (20) has its both ends cut at an angle of 45 degrees and includes:
• a first connection space (21) formed in the direction of the length of the horizontal bar (20) so that the inner space of the horizontal bar (20) is open to the outside,
• a screw fastening part (22) with a screw fastening groove (23) protruding in the first connection space (21), and
• first reinforcing part receiving channels (24) respectively formed at both inner sides of the horizontal bar (20);
• the vertical bar (30) has its both ends cut at an angle of 45 degrees to form a joint of 45 degrees when each of the ends of the vertical bar (30) faces each of the ends of the horizontal bar (20) and includes:
• a second connection space (31) formed in the direction of the length of the vertical bar (30) so that the inner space of the vertical bar (30) is open to the outside,
• a screw hole (33) formed on a side wall (32) in the second connection space (31), to be aligned with the screw fastening groove (23), and
• second reinforcing part receiving channels (34) respectively formed at both inner sides of the vertical bar (30);
• the reinforcing piece (60) includes:
• a first reinforcing part (61) to be inserted into the first reinforcing part receiving channel (24) of the horizontal bar (20), and
• a second reinforcing part (62) to be inserted into the second reinforcing part receiving channel (34) of the vertical bar (30);
• and
• the joint screw (40) is fastened to the screw fastening part (22) of the horizontal bar (20) and the side wall (32) of the vertical bar (30) to connect the horizontal bar (20) and the vertical bar (30), and
• wherein more than one screw fastening part (22) is formed in the first connection space (21) of the horizontal bar (20) and a corresponding number of the screw holes (33) to the number of the screw fastening parts (22) are formed in the side wall (32) of the vertical bar (30).