| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunnel excavator which can be propelled without being influenced by the condition of the ground and can be easily moved rearward and prevented from slipping sideways so that devices can be protected when the ground collapses. SOLUTION: A crawler 13, as a propulsion and retreat engine, is provided in a cutter holder 3 provided with cutters 2 for excavating the ground, and supporting plates 15, 16, each of which can move in radial directions of an excavated bore so as to contact the inner surface thereof, are provided in the cutter holder 3. For advancing the holder 3, the plates 15, 16 are brought into contact with the inner surface of the excavated bore and the holder 3 is propelled by the crawler 13, whereupon the holder 3 is advanced, being guided by the plates 15, 16, and hence the holder can be prevented from slipping sideways. For retreating the holder 3, the plates 15, 16 are moved radially inwardly to separate the plates away from the inner surface of the bore and the crawler is driven reversely. Since the holder 3 is advanced by the crawler 13, there is no need to push the bore by means of gripper so that propulsion can be effected regardless of the condition of the ground. Since the ground is supported by the plates 15, 16, devices in the holder can be protected from the collapse of the ground. |
