| 摘要 |
PROBLEM TO BE SOLVED: To easily change an underground excavator to cutter torque adapted to a property of natural ground changed in the middle of excavation by arranging a variable mechanism of the turning radius and hydraulically actuating plural driving jacks having a specific stroke on cranks continuously connected to an input side end of cutter rotary shafts. SOLUTION: Driving jacks 19a to 19e arranged in the radial direction to a driving jack fixing part 18 have a stroke of at least two times a maximum turning radius of cranks 14a to 14e, and are hydraulically actuated. Respective crank arms 15 of the cranks 14a to 14e are provided with a variable mechanism capable of changing a turning radius of the cranks 14a to 14e continuously connected to an input side end part of cutter rotary shafts 12a to 12e. A property of natural ground changes in the middle of excavation, for example, when requiring to increase torque, a rod side end part of the driving jacks 19a to 19e is replaced with an installing hole 16' from an installing hole 16 arranged in the crank arms 15 of the cranks 14a to 14e to enlarge the turning radius of the cranks 14a to 14e. |
