| 摘要 |
The present invention relates to a door closer comprising a door frame installation unit which is fixed to a door frame and has a hook formed at the end; a support unit whose one end is connected to the door frame installation unit to be rotated; a door installation unit which is installed in a door and has a guide hole formed lengthwise in the width direction of the door; a coil spring whose one end is connected to the hook of the door frame installation unit and the other end is connected to the support unit; a first door operation speed control unit which is installed between the support unit and the door installation unit and controls the opening/closing speed of the door; and a second door operation speed control unit controlling the opening/closing speed of the door by controlling a rotation speed of the support unit rotated in the door frame installation unit. The present invention may reduce maintenance costs as the door closer is rarely malfunctioned. The door closer also does not have hydraulic oil. Therefore, the door closer is environmentally friendly, and the opening/closing speed of the door can be easily controlled. |
