| 摘要 |
PURPOSE:To reduce the scraping torque for debris and effectively discharge it by dividing a cylindrical cutter which excavates a rectangular cross-section tunnel into a pair of a drum cutter and a ring cutter. CONSTITUTION:Drum cutters 22, 22 are turned via flanges 20A, 20A stuck to shafts 20, 20, respectively. Since the turning torque of a gear 52 is transmitted to the shaft 2 via the gears 54, 56, two ring cutters 26 and 26 are turned via shafts 24, 24, respectively. As a result, the drum cutters 22, 22 and ring cutters 26, 26 are turned counterclockwise (as shown by an arrow A) to excavate the ground 66 with cutter bits 28, 28. In this case the external end part 22A, 22B of the drum cutters 22, 22 are set as to excavate the ground by approximately the same width. The ground 66 may be therefore excavated in the rectangular cross-section form having approximately the same width as the lining 12. |
