| 摘要 |
PROBLEM TO BE SOLVED: To adjust the bending repulsive strength by forming adjuatment holes adjusting a bending strength at a specified ratio in a bend connecting the container body and the cover body. SOLUTION: A bend 3 is arranged to connect a container body 1 and a cover body 2 at the middle part along the container body 1 forming a container recess 11 and the cover body 2 and the whole body is integrally and ptotrusively formed. Three longitudinally extending oblong through holes 4 for adjusting strength are formed at every specified distance. The ratio of the sum of length of these three oblong holes 4 to the total length of the bends 3 is made as much as about 60%. The restoring repulsive force generated when the bend 3 is bent is reduced by about 60% as compared with the bend where oblong holes are not formed. Even if the cover body 2 is gradually raised while using the bends 3 as the bending support joints and moved so as to superimpose the cover body on the container body 1, the bend 3 can be easily and flexibly bent owing to such a constitution and it is not necessary that the container body 1 is pulled up and the inclined condition is changed. |
