The present invention discloses an expandable casing capable of selectively opening a perforation hole formed in a ground. The expansion type casing according to the present invention comprises a casing for grounding and a casing. And a wiper blade detachably coupled to a distal end of the casing, the wiper blade being provided at a plurality of openings formed in a side surface of the body and rotatably coupled to the body by a rotation axis, Shaped bit, and one end of the wing-shaped bit protrudes to the outside of the body when a hole penetrating the inside of the body through the casing strikes the opening protrusion. According to the present invention, when a hole is required to be extended, a hole is inserted into the casing to release the locking state of the wing-type bit, so that a necessary portion can be selectively and conveniently wired. In addition, since the drilling hole can be extended by combining the shoe factory with the existing casing, there is an advantage that the conventional casing drilling equipment can be used as it is.
展开▼
