| 摘要 |
PURPOSE:To not only prevent displacement or the end part or a shield jack from the central position of a segment during folding-inside of a shield body but also prevent wear of the packing of a piston rod. CONSTITUTION:A front drum support type folding-inside type shield augering machine has a plurality of shield jacks 9 which is rockably inserted in ring girders 10 and 12 arranged in a shield body and has a front part, rockably supported to a support member 2 of a front shield 1, and a rear part pressed against a segment 6 through a shield jack spreader 17. A hydraulic cylinder 30 is attached between the shield jack 9 and a ring girder 10 so that it is reciprocated in the radial direction of a shield body. During folding-inside of the shield body, the shield jack 9 is moved toward the inner peripheral side of the shield body by a necessary distance by the hydraulic cylinder 30. |
