AN INSERT FOR RELEASABLY RETAINING CUTTING MEANS IN A GROUND DRILL

摘要

An insert for releasably retaining cutting means in a ground drill, said insert comprising a substantially cylindrical member movable within said ground drill between an installation position in which said insert retains said cutting means in a cutting position between an outer circumferential surface of said insert and an inner circumferential surface of said ground drill, and a retrieval position in which said insert is retracted to release said cutting means from between said outer circumferential surface of said insert and said inner circumferential surface of said ground drill.