Patent attributes
A multi doorlock includes a doorlock unit (200) installed to a hinged door (100), a non-powered DC motor (300) installed to the doorlock unit, and links (400) (410) having one ends connected to the DC motor and the other ends installed to a doorframe, the links being folded or unfolded with each other when the hinged door is closed or opened. The doorlock unit (200) frequently changes a braking resistance of the DC motor (300) while the hinged door (100) is opened or closed, thereby controlling an opening/closing speed of the hinged door. A relay switch (700) is connected to both ends of a power line (330) of the DC motor (300) to short the DC motor on occasions. When it is intended to fix the hinged door (100), the relay switch (700) is operated to short the DC motor (300) such that the hinged door is not moved.
