| 摘要 |
PURPOSE:To enable to perform excavation through a single machine, by a method wherein a soft layer part in an excavating ground is excavated through rotation of a screw auger, and hard layer of cobble-stone and the like is excavated through hammering by a hammer and rotation of the screw auger. CONSTITUTION:A cylinder body 7 is brought into contact with a ground surface and a soft layer part at the upper layer part of a ground is excavated through rotation of a screw auger 1. After a cutter 6a of an auger 1 is lowered down to a hard layer part of limestone and the like, by feeding with a pressure a compressed air to an air cylinder 9 through an air passage 3 of a shaft 5 as the auger 1 is rotated, the compressed air pressurizes a piston rod 10 to bring a bit 12 into pressure contact with the hard layer part. When a pressure in the air cylinder 9 is increased, a valve 11a is opened, the compressed air is fed to the interior of the piston rod 10 and is exerted on a hammering member 13 to produce striking on the hard layer part by means of a hammer 8. |
