To provide a bolt falling prevention tool capable of preventing a bolt from falling down from a bolt hole and capable of being easily manufactured, an apparatus for flow control, and a manufacturing method of the bolt falling prevention tool.
This tool comprising a flexible material and preventing the bolt 5 from falling down by being fitted and retained in a spot facing part 24 formed on the bolt hole 23 is provided with a through hole 2 for locking and retaining the bolt 5 inserted into the bolt hole 23. Inside diameters Dha and Dhb of one end side 2a and the other end side 2b of the through hole 2 are larger than an outside diameter Db of a screw part 5a of the bolt 5, and a protrusion 6 having an inside diameter Dhc smaller than the outside diameter Db of the screw part 5a is formed in an intermediate part 2a of the through hole 2.
NAKAMURA HIROYUKI
IO NAOHIRO
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