| 摘要 |
<p>PURPOSE:To enhance the mechanical strength, by forming projecting lines on the outside face of a longitudinal frame in the longitudinal direction and by cutting off terminal parts of projecting lines in a part of the longitudinal frame, which is to be inserted into a lateral frame through a through-hole and by bringing cut end faces of these projecting lines into contact with the outside face of the lateral frame to join the lateral frame and the longitudinal frame. CONSTITUTION:Projecting lines 2 are formed on the outside face of a longitudinal frame 1 in the longitudinal direction. In case that the longitudinal frame 1 is connected to a lateral frame 3, terminal parts 2a of projecting stripes in a part of the longitudinal frame 1 which is to be inserted into the lateral frame 3 from a through-hole 5 of the lateral frame 3 are cut off, and cut end faces 2c of these projecting lines 2 are brought into contact with the outside face of the lateral frame 3, and left main parts 2b of projecting lines 2 become outside projecting parts. Therefore, these outside projecting parts have a mechanical strength higher than that of conventional outside projecting parts.</p> |
