| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive fastener, and to reduce assembling manhours for a manhole by molding the fastener by a stick, and forming a screw part as a structure that a pair of 1/4 circumferences are opposed in both male and female screws. SOLUTION: An anchor 5 (a female screw) is embedded in an oblique wall 4, an adjusting ring 3 is fixed by a ring bolt 6, and is joined to the anchor 5 by a male screw of the ring bolt 6, and is joined to a bonnet bolt 7 by a female screw so that a receiving frame is fixed by a nut 9 by inserting an adjusting washer 8 into this bonnet bolt 7. In a male screw part of the lower end of the ring bolt 6 and a female screw part of the upper end, screws 11 of 1/4 circumferences are opposed in pairs, and both the female screw part of the anchor 5 and a male screw of the bonnet bolt 7 are formed as a structure of 1/4 circumference. When connecting and fastening a fastener, a screw part of a male screw is inserted into a screw-unarranged part of the female screw to be rotated by 1/10 to 1/8 circumference. Thus, a cost of the fastener can be reduced, and assembling manhours of a manhole can be sharply reduced.
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