| 摘要 |
PROBLEM TO BE SOLVED: To separate cups satisfactorily, by making the angle of the inclination of the outside of a protective cover and the angle of the inclination of the inside of the main body of each cup different from each other, and by allowing, when superimposing the cups, the contact of the lower end of the outside of the upper cup with the inside of the lower cup. SOLUTION: The main body of a cup has a side wall 14, made of paper, formed as a cylinder of an inverted-truncated-conical shape and a bottom wall 16 closing the vicinity of its small-diameter end. A protective cover 20 having an inverted-truncated-conical shape is disposed so as to cover the entire outside of the side wall 14 of the main body of the cup. This protective cover 20 is formed into a taper structure where its thickness gradually decreases upward. In the taper structure, when the two cups 10 are superimposed one on top of the other, a gap is made between the outside of the upper cup 10 and the inside of the lower cup 10, because the angle of the inclination of the outside of the protective cover 20 is smaller than that of the inside of the main body of the cup. Therefore, a static friction force which occurs between the cups 10 is small, and the upper cup can be pulled from the lower one with a small force. |
