| 摘要 |
A reamer assembly for widening a drilled pilot hole or for widening a hole that has been widened in a first step in a down-the-hole drilling operation, includes a shank (14) for attachment of the reamer to the end of a down-the-hole hammer drill and a conical drill bit or crown (15). The conical bit (15) of the reamer is divided into at least three segments (18) which are terminated with a transverse end surface (21) that directly connects the conical segments and at least three of the segments (18) include drill buttons (16) that are disposed equidistantly from the centre axis of the drill bit (15). |
