SHIELD JACK

摘要

PROBLEM TO BE SOLVED: To provide a shield jack for surely preventing the front end part of a segment from being damaged due to the decrease in the contacting area of a spreader and the front end face of the segment from being damaged due to the side deviation of the end part of the spreader. SOLUTION: A shield jack 4 that has a spreader 12 where the degree of freedom in the direction of a normal line H of a contacting surface T that comes into contact with a front end face Z of a segment 2 after assembly at a rear end part and is arranged with a proper interval in the circumferential direction of a shield tail part is provided with a spreader restriction means 13 for restricting the rotation of the said spreader 12 around the normal line H by connecting those being adjacent out of a plurality of spreaders 12 that are selected arbitrarily according to the layout of the segment 2.