| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve strength of a connecting part without impairing overall beauty by regulating engaging height of screws, in a stackable lunch box using the screws. <P>SOLUTION: When a screwing height in the male screw cylinder 21 of a middle container 3 is defined as Ho, and the outer diameter of a lower container 2 and the middle container 3 is defined as W, the stackable lunch box is formed so that W/3>Ho>W/8 is satisfied. When the screwing height is defined as Ho, and the total height of the entirety in the stacked state including the middle container 3, an upper container 4, and a covering container 5 is defined as Ht, the lunch box is formed so that Ht/5>Ho>Ht/12 is satisfied. By making the outer diameter W and the ratio of the screwing height Ho to the stacked height (height of the entirety) Ht equal to or greater than a fixed value, a sufficient fitting strength can be obtained. Furthermore, by regulating the engaging height of the screws, the strength of the connecting part can be improved without impairing the overall beauty. <P>COPYRIGHT: (C)2012,JPO&INPIT |
