| 摘要 |
In a rotary earth drill in which sockets are welded to and spaced around a head and drill bits are removably mounted in the sockets, the sockets having a surface exposed to abrasion when the drill is rotated in the earth, a shield in the form of a shroud or jacket is provided, removably mounted on the socket, and extending around the otherwise exposed surface of the socket to protect the socket surface from abrasion. When the shield itself becomes worn, it can easily be removed, in much the way in which the bits are removed, and replaced. In order to accommodate the weld by which the socket is secured to the drill head, the shield is provided with a slot, open at at least one end. The slot is wide enough to permit side edges defining the slot to straddle the weld.
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