DRILLING DEVICE AND DRILLING METHOD FOR INVESTIGATING BURIED METAL OBJECT

摘要

PPROBLEM TO BE SOLVED: To form a drilled hole for investigation reaching a buried metal object without providing damage to the buried metal object. PSOLUTION: This drilling device comprises a propelling drive shaft 20 having a drilling blade 21 and a drive means 22 for rotatingly driving the propelling drive shaft 20. An end contact member 24 is fitted to the end of the propelling drive shaft 20 to be rotatable around the axis of the propelling drive shaft 20. One end of a conductor 4 the other end of which is conducted and connected to the ground part 1A of a metal tube 1 is connected to a connection terminal 26 installed at the base end of the propelling drive shaft 20 through a power supply 30 and an alarm means 31 connected to the power supply. The connection terminal 26 is conducted to an end contact member 24. The end contact member 24 is brought into contact with the surface of the metal tube 1 to close the circuit for operating the alarm means 31. PCOPYRIGHT: (C)2008,JPO&INPIT