Takata Corporation

Nisshin Steel Co., Ltd.

Hideto Hashimoto

Naofumi Nakamura

Hirokazu Sasaki

Yoshihiko Kawai

Takaaki Kimura

Shigeru Morikawa

When forming a dowel section by performing press working on each of portions constituting side walls of a buckle base member, a die having a negative clearance with a punch portion () is used whose length or diameter is larger than a length or diameter of a die portion (). The dowel section is required as a guide for a tongue inserted into a buckle and as a load receiver when a latch member is elongated at a time of collision etc. When a ratio C/t of a clearance C between the punch portion and the die portion with respect to a plate thickness t of the buckle base member is set within a range of &#x2212;(30 to 5) %, no crack is generated in the root of the dowel section, and the dowel section of a shear cross-section length &#x2267;0.25&#xd7;t, a shear cross-section starting height &#x2267;0.7&#xd7;t, and a height of (0.70 to 0.95)&#xd7;t is easily obtained, and the perpenducularity of the dowel section side surface is enhanced.

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Tokyo, Japan

Hideto Hashimoto