| 摘要 |
PURPOSE:To bring a flat surface into contact with a carrier at points or on lines, by providing a plurality of projections to side surfaces having no overhanging section on an upper surface and a lower surface and the sides of corresponding upper surfaces and making the projection have a three-dimensional shape whose uppermost section is a point or a line. CONSTITUTION:Four projections 1 are provided respectively to an upper surface 12, a lower surface 13 and a side surface 14. The projection 1 is formed to have a three- dimensional shape whose uppermost section is formed into a point or a line such as a hemispherical shape. When a carrier is placed onto a flat surface from the direction of the arrow B or the arrow A or the arrow D so that the upper surface 12 or the lower surface 13 or the side surface 14 are brought into contact with the flat surface, the four projections 1 on respective surface are brought into point-contact with the flat surface. When the carrier is positioned onto the flat surface from the direction of the arrow E, the flat surface is brought into line-contact with either two or all of an arris 6 on the lower side of an overhanging section 3, arrises 9 on the lower side of side surfaces 17 and an arris 10 at the lower end of a surface connected to the lower surface 13 because the overhanging section 3 is formed to the upper surface. |
