LOCKING DEVICE OF MANHOLE COVER

摘要

PROBLEM TO BE SOLVED: To provide a locking device of a manhole cover capable of facilitating the unlocking/locking work of the manhole cover and uniformizing load to be applied on the manhole cover. SOLUTION: An arm 4 is linearly moved in the direction of the diameter of a rotational board 7 along a spiral groove 7d formed in the rotational board 7 capable of being rotated with the approximately center of a manhole cover 1 ad the rotary center. The arm 4 is interlocked with an interlock 3a of a cover frame 3 and is locked, and it is sheltered from the interlock 3a and is unlocked.