To provide a portable drill capable of boring a hand hole in a metal door without requiring a power source, or without generating sparks from a main body.
For example, an impeller 8 is rotated by water of high flow speed and high pressure supplied from a fire engine, a carrier 9a provided with a two-stage planetary gear 9d comprising a large diameter gear part and a small diameter gear part is rotated by a sun gear 9c rotated by the impeller 8, an inner rotary shaft 11 having a drill 13 on a tip is installed on the carrier 9a rotated to rotate, an outer rotary shaft 10 engaged outside the inner rotary shaft 11 and having a hole saw cutter 12 on a tip in such a way that a cutting edge 12a is retracted from a tip of the drill 13 is rotated by a rotary internal ring gear 9f engaged with the two-stage planetary gear 9d to be rotated at lower speed than the carrier 9a, and water is jetted toward the tip of the drill 13 from a jet nozzle 11b.
HIGASHIYAMA MASAHIRO
TAKEMOTO HIROSHI
COMMUNICATION SCIENCE CORP
AIC KK
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