| 摘要 |
<p>Provided is an excavation tool for efficiently taking waste rocks produced during excavation into the inner peripheral side of a casing pipe and discharging the waste rocks to the outside. An excavation tool (10) includes a casing shoe (11), a casing pipe (15), a rod (60), a device (40), and an excavation bit (20). A discharge flute (46) for discharging the waste rocks is formed in the outer peripheral surface of the device (40). The excavation bit (20) has a head portion (22) and a skirt portion (23). The device (40) can be inserted into the inner periphery of the skirt portion (23). The head portion (22) is provided with:
a face flute (27), which is open into the tip face of the head portion and extends radially outward;
a connection flute (28), which is integrally connected to the outer peripheral end of the face flute (27) and extends toward the rear end side, and
an intake hole (29), which is integrally connected with the discharge flute (46) of the device (40) and is open to the inner peripheral side of the skirt portion (23) from the connection flute (28). A shield wall (35), which extends radially outward beyond the external diameter of the casing shoe (11), is formed at the rear end of the connection flute (28).</p> |
