| 摘要 |
The present invention relates to an expansion rod for perforating the ground, capable of easily releasing an engaged state thereof in such a manner that a first rod performs a normal rotation and a reverse rotation while the first rod is elevated up, and a second rod is interlocked therewith when the rod is not rotated anymore since the contracted rod is engaged with the ground. According to the present invention, the expansion rod for perforating the ground comprises the first rod and the second rod. The first rod has a predetermined length, has a head positioned on a lower end, and has at least one first locking protrusion formed on the outer circumference of the head at a predetermined angle. The second rod comprises a screw, a hollow, an upper deviation preventing jaw, a lower deviation preventing jaw, a second locking protrusion, and a third locking protrusion. The screw is formed on the outer circumference of the second rod. The hollow is formed on the interior of the second rod to receive the first rod. The upper deviation prevention jaw and the lower deviation prevention jaw are formed on the inner circumferences of the upper part and lower part of the hollow, respectively, to prevent the head from being deviated from the hollow. The second locking protrusion is formed on the inner circumference of an upper side of the hollow to correspond to the first locking protrusion. The third locking protrusion is formed on the inner circumference of the lower side of the hollow to correspond to the first locking protrusion. The third locking protrusion has an L-shaped extended part to receive the first locking protrusion when the first rod is elevated. |
