Core recovery manner and core recovery device null of all casing

摘要

PROBLEM TO BE SOLVED: To efficiently recover a core even when the excavating diameter is large and the ground is hard. ;SOLUTION: When a core 18 formed in the inside of the front end casing 1 is recovered in the all easing work method, a core-holding means constituted of a plurality of pressing structures provided with a guide member 9, a contact member 10, and a jack 11, is equipped at the outer cylinder 2 which is inserted in the front casing to cut the outer peripheral part of the core 18 by roller bits 3a, 3b. And also a plurality of core cutting means constituted of pressing structures with a guide member 12, a contact member 13, and a jack 14, are provided. The contact members 13 of a plurality of core cutting means are vertically moved alternately by the jacks 14 and guided by the guide members 12 to alternately actuate lateral forces like wedging forces on the core 18 by the contact members 13 and cut the core 18. On cutting the core, similar lateral forces are simultaneously given on the outer peripheral part of the core 18 by a plurality of contact members 10 of these pressing structures to hold the core 18 in these cooperation.;COPYRIGHT: (C)1997,JPO