| 摘要 |
PROBLEM TO BE SOLVED: To provide an over-door capable of giving an upward force to a door panel using a weight. SOLUTION: A door panel 4 of an over-door is moved vertically to bring into closed and opened states with a drive chain 19 wound on a drive sprocket 16 of a shaft 10. A weight sprocket 22 is fixed to an auxiliary shaft 21 rotated in connection with the shaft 10, one end part of a weight chain 27 is connected to a chain 25 wound on the weight sprocket 22, and an upward force is given to the door panel 4 by the weight of the weight chain 27. The other end of the weight chain 27 is bent upward and fixed so as to decrease the effective length of the weight chain 27 when the door panel 4 rises, and increase the effective length of the weight chain 27 when the door panel 4 lowers. Thus, an upward force can be given to the door panel 4 using a weight, and the upward force is decreased gradually as the door rises from the closed state to the open state and increased gradually as the door lowers from the open state to the closed state.
|
