| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield machine having a mechanism in which the cutter bit can be replaced without causing difficulty on design. SOLUTION: In this shield machine, a plurality of fist revolving seats 6 each of which is fitted with three first cutter bits 5 are provided so as to be revolvable around an axis (b) almost in parallel with the axis (a) which is parallel to the rotating axis of the surface plate, and this first revolving seat 6 is made up of the rotating shaft part 12 rotatably supported by a cutter spoke 4 and the seat plate part 13 provided to one end of the rotating shaft part 12 and to which the first cutter bits 5 are fitted. A first rotatable driving device 7 for rotating the rotating shaft part 12 of each of the first revolving seats 6 is provided the side of the cutter spoke 4, and the three first cutter bits provided to each of the first revolving seats 6 is made to be replaceable in the position between the excavating position 5A and the receding positions 5C, 5B, and the excavator is provided with a fixing device 8 for fixing the rotation of the rotating shaft 12 of each of the first revolving seats 6. |
