| 摘要 |
PROBLEM TO BE SOLVED: To excavate a facing in a stable state by stirring and mixing sludge and cut sufficiently, to facilitate discharge of mud by increasing the fluidity of discharged mud and earth and further to enable execution of excavation in a noncircular shape, e.g. in a square or elliptical shape. SOLUTION: Three horizontal rotating shafts 16 are fitted at positions being aside from the center of rotation of a rotating body 11 in the front of the front end of a shield machine A and a bit fitting board 21 is provided at the tip of the rotating shaft 16. A plurality of bits 22a are provided on the bit fitting board 21 at different distances from the axis of the rotating shaft 16, while a ring-shaped inner gear 19 is provided inside an outer casing 10 of the rotating body 11. A gear 18 of a planet gear engaging with the inner gear 19 is fitted axially to the axis of the rotating shaft 16, so as to rotate the bits 22a around the center of the rotating body 11 and around the rotating shaft 16. |
