| 摘要 |
PROBLEM TO BE SOLVED: To provide a cap for a writing utensil of such a construction that the easy lapping of a decorative member over a cap body with a curvature formed on the surface is achieved even when both are to be firmly welded together by using an ultrasonic welder and also their secure welding is ensured. SOLUTION: A groove part with a bottom face extending across almost the overall length of the cap body, is formed on its surface and a joint face to be fitted to the bottom face of the groove part, is formed on the back of the decorative member and further, a projecting part extending in the barrel direction, is formed in the center of the groove part of the cap body. in addftion, a recessed part to be engaged with the projecting part is formed in the center of the decorative member and a hole part is formed at the end of the groove part positioned near the crest part of the cap body and further, a protrusion to be engaged with the hole part is formed at the end of the decorative member so that the projecting part of the cap body is engaged with the recessed part of the decorative member. Further, the protrusion of the decorative member is engaged with the hole part of the cap body and finally the the bottom face of the groove part of the cap body and the joint face of the decorative member are welded using the ultrasonic welder. |
