| 摘要 |
PROBLEM TO BE SOLVED: To open a door easily while sufficiently obtaining the closing force of the door. SOLUTION: Force in the closing direction is worked to a door 2 by the door closer 4 between the door 2 and the fixing side 3 supporting the door 2, the door 2 is closed automatically, and the resilient force of springs 7a, 7b working in the closing direction of the door 2 of the door closer 4 is made lower than a set value temporarily by a closing-force reducing means 35 in relation to the information of the entrance and exit of a person for holding the door 2 at the place of closing, and the decrease of door-opening resistance by the door closer 4 at a time when the door 2 is opened by a person is prepared.
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