Fuel tank cap and method of manufacturing the same

摘要

A fuel tank cap structure and method of manufacturing which prevents a parting line formed on a cover member in the process of injection molding from being undesirably shaven. The fuel tank cap includes a casing body and a cover member that is rotatable in one direction relative to the casing body via a ratchet mechanism when a torque of or above a predetermined level is applied to the cover member. The cover member has fitting projections that are held by an outer ring member of the casing body. A slide mold is used for manufacturing the cover member having the fitting projections that are undercut in the injection molding. This causes a parting line to be formed on a top wall of the cover member. Anti-shaving projections formed at substantially the same height as that of the parting line prevent the parting line from being slid against the outer ring member and shaven.