| 摘要 |
<p>A hammer is mounted on a support moved along a slide by a motor and joined by a tup-pallet to the piercing tool consisting of a cutter joined by a male or female connection to a tube of smaller ida. than itself. The back of the tube is joined to a threaded sleeve which may be blind ended or open at both ends. The cutter has lips at the end in which there are compressed air holes to blow away the dust. The tool may be used on any conventional apparatus. The cutter and tube are thrown away after the piercing operating.</p> |
