PURPOSE: To prevent digging chips from infiltrating into an axial hole of a digging tool while efficiently removing the digging chips by providing an exhaust hole in the center of a device, forming a through hole in a block shaft and connecting the exhaust hole to the axial hole by the through hole.
CONSTITUTION: When a device 2 is rotated in a digging direction, one end part of straight end faces 15a, 15b of blocks is protruded from the peripheral surface of the device 2 by turning the blocks 11a, 11b. Further the straight end faces 15a, 15b are adapted to each other to stop turning of the blocks 11a, 11b, and the device 2 excavates the ground to advance by bits 4... and impact force of a hammer by receiving turning force of the device 2 to the blocks 11a, 11b. Air, compressed by dropping a hammer piston, is inflow-jetted to through holes 18a, 18b from an exhaust hole 17 to remove digging chips. In this way, infiltration of the digging chips can be prevented by generating a positive pressure in axial holes 2a, 2b relating to the bits 4....
SATO SHIGERU
TSUJIMOTO KATSUAKI
| JPS5976391A | 1984-05-01 |
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