| 摘要 |
PURPOSE: A safety device for preventing an entrance door from being suddenly closed is provided to prevent sudden closing by discharging air of a cylinder with the resistance of a damping valve. CONSTITUTION: A safety device for preventing an entrance door from being suddenly closed comprises a main body (11), an elastic member (12), a piston (13), a roller (14), a damping valve (15), and a noise preventing device. The main body includes a cylinder unit and an entrance hole and is installed on the inner side of a door frame. The elastic member is arranged on the cylinder unit and includes a piston head and a piston rod. The damping valve delays air discharge of the cylinder unit and increases the inflow of the air. The noise preventing device pressurizes the roller by being installed on the inner side of the entrance door. |
