EXTREMELY DEEP BASE ROCK EXCAVATING DEVICE

摘要

PURPOSE:To prevent the dislocation of center at the time of excavation by connecting a small diameter rod to the end of a casing, and connecting a base rock excavating means to the end of the rod, and further slidably providing a run-out preventing device having a pressing plate capable of being projected to the side, on the outer circumference of the rod. CONSTITUTION:A driving device 2 is comprised of a motor 3, a speed reducer 4, and a chuck device 5 provided on the outer circumference of a casing, and it is elevatably connected to the leader of a short length leader mast which has been erected on a base machine or the like. And at the end of the casing 6, a hollow rod 7 having a smaller diameter than the casing is connected, and a base-rock excavating means 8 is connected to the end of the rod. And to this rod 7, a run-out preventing device 10, in which a jack 10b is horizontally fitted to a flat rectangular housing 10a and a pressing plate 11 is fitted to the side of the jack 10b, is slidably provided, and a lockedly engaging flange 7a is projectedly provided at the end of the rod 7. Thus, an extremely deep base rock layer can be properly excavated without dislocation of center.