| 摘要 |
PROBLEM TO BE SOLVED: To provide a fixed device of a manhole cover capable of simply making locking operation or unlocking operation of the cover by one person alone. SOLUTION: A latch 5 interlocking with a lock section 2a of a body frame 2 is pivoted by the lower end of a main shaft 4 with a horizontal pivot 6, the main shaft 4 inserted into a main body cylinder 3 in a rotational manner and a vertical movable manner is pushed up by a coil spring 7 to energize, and the latch 5 is rotated by biased dead weight between the front end interlock section 5a and a backward weight section 5b. By the constitution, spring pressure of the coil spring 7 is set in such an extent that the spring pressure can be compressed by load of body weight for one person.
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