PURPOSE: To simplify the joining work, to reduce the cost and to prevent the reduction of the strength due to the heat effect during the welding and the generation of the distortion.
CONSTITUTION: A groove 3 which is opened upward is formed in the left edge part of a right panel 1, and at the same time, projecting walls 4, 5 which are projecting toward the mutually opposite side walls 3b, 3a are formed to the upper end of the side walls 3a, 3b of the groove 3. A downward projecting wall 9 is formed on the right edge part of a left panel 2, and an expandable part 10 which is of the shape to be fitted in the groove 3 of the right panel 1 and has an expansion margin 11 of approximately V-shaped section at the middle of the width is formed continuous to the lower edge of the downward projecting wall 9. The panels 1, 2 are combined so that the expandable part 10 of the left panel 2 may be located within the groove 3 of the right panel 1. The expandable part 10 is deformed so as to increase the width by applying pressure from the top, the respective side edge parts are stretched between the side walls 3a, 3b of the groove 3 of the right panel 1, and press-fitted between the projecting walls 4, 5 and the bottom surface of the groove 3 to fix the panels 1, 2 to each other.
SUGIO EIJI
OGASAWARA HIROKI
