Lap it constitutes 4 it possesses lap the side frame

摘要

PROBLEM TO BE SOLVED: To solve the problem in the conventional technique relating to a perimetric side frame assembled in a square by butting together and joining the ends of four perimetric side pieces and provide what surpasses a conventional product in stability of the joints. ;SOLUTION: A perimetric side frame 20 is composed of four perimetric side pieces 10 having slanted ends 11, 11 cut slantingly at 45° and formed into a square assembly by butting the slanted ends 11, 11 against each other in joining them. Of the slanted ends 11, 11 for the mutual butt joint, a hollow part 12 is formed on one at right angles to the slanted end and a projecting part 13 is formed on the other at right angles to the slanted end, the hollow 12 and projection 13 being designed to be fitted together. Therefore, with the hollow and projection fitted together in a direction making right angles to the slanted ends the mutual butt joint between the slanted ends cut slantingly at 45° of the respective perimetric side pieces can be increased in stability.;COPYRIGHT: (C)1998,JPO