STRUTTURA DI CHIUSURA DI TOPPA DI SERRATURA.

摘要

A keyhole-shutter structure includes a cylindrical protector block. An upper portion of the protector block includes an approximately square housing portion. A shutter plate is fitted in the housing portion. A cap is placed on the protector block. The bottom of the housing portion has right and left receiving planes for receiving the shutter plate, and a recess formed between the right and left receiving planes in such a manner as to be curved downwardly. Since a recess is provided between right and left receiving planes for receiving a shutter plate, even if the shutter plate is somewhat deformed, the deformed portion interferes to a lesser extent with the recess. Accordingly, a key can be easily inserted into a keyhole even if the shutter plate is somewhat deformed.