| 摘要 |
PROBLEM TO BE SOLVED: To prevent a dead bolt from coming off a retainer part or make the dead bolt hardly come off the retainer part, even when a sheet metal door is deformed with a destructively strong force, in use in the state of attachment to the sheet metal door.SOLUTION: A dead bolt lock, in which a dead bolt D34 includes a dead bolt body 3 and a latch 4, comprises a dead bolt extension mechanism. Ordinarily, the dead bolt D34 is butt-joined to a butt joint member and pre-engaged with a retainer part at normal protrusion length. In an emergency in which the dead bolt D34 is pulled away from the retainer part because an external force is destructively applied to a door, the dead bolt D34 is extended following the butt joint member on a door frame side, and engaged with the retainer part with protrusion length greater than the normal protrusion length. |
