To execute highly precise excavation work with real-time excavation information such as tilt angles obtained without depending on signal cables.
An excavation information detector 11, an acoustic oscillator 12, and a receiving body 13 provided at the ground side for receiving signals from the acoustic oscillator 12 are arranged. Excavation information signals from the excavation information detector 11 are sent by wire to the accosting oscillator 12, and the acoustic oscillator 12 is oscillated in accordance with the excavation information signals. Then, oscillation is converted into acoustic vibration of an excavation shaft 6 and sent to the receiving body 13 with the excavation shaft 6 working as a transmission medium. The acoustic vibration is then converted into electric signals at the receiving body 13, and thereby the excavation information signals are obtained.
WATANABE AKIRA
TANIGUCHI RYOSUKE
SAKAMOTO TAKAHIRO
SHIMADA TAKASHI
