| 摘要 |
The present invention relates to door closer for fire door adapted to rapidly and firmly closing a fire door when a fire occurs and adapted to easily and gently open the fire door in normal states, the door closer including: a body; and an auxiliary part connected to the body by means of a bracket, the auxiliary part including an operator disposed at the inside of a housing by means of a spring and having a groove formed on the front end thereof, a ball member housed into the groove formed on the operator in such a manner as to be linearly moved therealong, and an operating cylinder adapted to guide the ball member linearly moving on the operator to first to third sliding pathways formed thereon so as to change a door-rotating force caused by the body to multiple steps. |
