SPRINKLER FOR DRILLING MACHINE

PURPOSE:To prevent the flooding into a speed reducer by watertightly and rotatably inserting a rotary seal shaft communicated to an injection nozzle into a rotary seal casing and providing a drain waterway inlet in contact with the seal shaft. CONSTITUTION:A pressure waterway 4 in a carrier 3 is connected to a rotary seal casing 21 via an O-ring 22, a rotary seal shaft 5a is rotatably inserted into the opening tube section 21b of a vacant chamber 21a. The water hole 5b of the shaft 5a is communicated to an injection nozzle 10 via the waterway 24, the inlet of a drain waterway 25 is opened in contact with the shaft 5a. Pressure water is sprayed through the nozzle 10 while a drilling drum 6a is rotated via a solar gear 14 or the like in the carrier 3, on the other and the leakage water from the rotary contact face of the shaft is discharged through a drain port 25d via the waterway 25. The leakage water into the drum 6a of a speed reducer or the like can be prevented.