To provide a kelly-bar structure capable of supplying a filler such as a cement milk in an earth drilling machine having a telescopic kelly-bar.
This kelly-bar of an earth drilling machine includes an outer kelly-bar 15; a guide pipe 16 contained in the outer kelly-bar 15 rotatably and unmovably in the axial direction in such a manner that the upper section thereof projects from the outer kelly-bar; co-rotation suppressing means 24, 25 for suppressing the co-rotation of the guide pipe 16 when the outer kelly-bar 15 is rotated; a swivel joint 30 which is contained in the guide pipe 16 unrotatably and movably in the axial direction and which has, at the upper end, a connection section 41 for a hoist rope and a connection section 42 for a supply hose for supplying a filler such as a cement milk; and an inner kelly-bar 17 which is contained in the outer kelly-bar 15 movably in the axial direction, to which rotation is transmitted from the outer kelly-bar, the upper end of which is rotatably connected to the swivel joint 30, and which communicates with the connection section 42 for the supply hose.
YABUUCHI SADAO
TAKAJIRI MASARU
INOUE MISAO
OIGAWA MITSUMASA
