PROBLEM TO BE SOLVED: To solve the problem that a chip removing means cannot be used with a water stream in forming a diversion hole when newly placing a water distribution main pipe or setting the diversion hole in a water distribution main hole in an empty pipe condition with no water pressure in the water distribution main pipe, to bring about incomplete chip flying prevention or chip removal, resulting in the entry of chips into a fitting mechanism or a snap tap mechanism part during hole formation to generate a failure or water leakage.;SOLUTION: In a mechanism protecting method, a passing water hole 13a of a snap tap ball valve element is set vertical to form an insertion space ranging from the upper part to the upper face of the water distribution main pipe in the empty pipe condition, and a cylindrical plate 3 with a locking structure 31 is inserted into the upper end to encircle the insertion space so that chips produced during hole formation with a hole forming drill is enclosed in the cylindrical plate to prevent the dispersion into the snap tap mechanism.;COPYRIGHT: (C)2009,JPO&INPIT
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