Vacuum insulation cup lid

Abstract

Disclosed is a shank of a four-piece forging of golf club head. A top piece of the four-piece forging of club head forms, at a portion thereof adjacent to the shank, a two-staged structure of an outward flaring sector-shaped connection portion that is combined with the shank, whereby an abutting condition exhibiting a smooth surface is formed at a jointing site between the shank and the club head in the course of performing welding operation between the shank and the club head for reducing the amount of filling material used in carrying out the welding operation and making the welding operation, as well as the subsequent grinding operation, easier and smoother. Thus, with the quality improved, the flexibility of design can also be enhanced to reduce the machining time and the manufacturing costs.

1 . A vacuum insulation cup lid, comprising an outer side wall and an inner side wall formed integrally on an end face and a side wall of a circumference thereof, and a vacuum heat-insulated space being formed between said outer side wall and said inner side wall and extending completely along the end face and the side wall of the cup lid and being completely free of substance contained therein, the inner side wall having an inner diameter on which an internal thread is formed.