EXCAVATOR FOR VERTICAL BORES

摘要

A vertical hole excavating machine has a cutter head (16) comprises: a first head (24) supported rotatably about the axis (14) of a cylindrical shield body (12) at the lower end of the cylindrical body (12) and having a central space vertically extending therethrough; at least one first cutter (26) mounted on the first head to excavate earth under the first head; a second head (28) disposed coaxially in the central space so as to be mounted or dismounted from above, and having a cylindrical portion (62) for receiving matter excavated by the first cutter therein and a bottom plate (66) for closing the lower end of the cylindrical portion; and at least one second cutter (30) mounted on the second head to excavate earth under the second head. It is characterized in that the second head (28) is further provided with a notch to receive matter excavated by the second cutter (30) into the cylindrical portion (62). <IMAGE>