| 摘要 |
PROBLEM TO BE SOLVED: To prevent external light from entering from a gap between a guide rail and a pull cap by making the inclination angle of the guide rail in the thickness direction of the pull cap in a section perpendicular to the moving direction of the pull cap within a specified range. SOLUTION: In the section perpendicular to the moving direction of the pull cap 5 of the guide rail 9, when the inclination angleθof the guide rail 9 to a reference line L in the thickness direction of the pull cap 5 becomes large on the outside (+ side), the gap between the pull cap 5 and the guide rail 9 becomes large, and a light shield property is deteriorated. When it becomes large on the inside (- side), the gap between the pull cap 5 and the guide rail 9 becomes small, and the operation resistance of the push-pull operation of the pull cap 5 is increased. The inclination angleθof the guide rail 9 is preferably made within the range of -1.5 deg. to +1.5 deg.. A main cause that the inclination angleθis changed exists in a temp. difference between a fixed side mold and a moving side mold of the mold for injection molding a pack main body 3. The inclination angleθlies within the allowable range by making the temp. difference 15 deg.C-45 deg.C.
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