| 摘要 |
<p>A number of substantially wedge-shaped reamers are arranged in an elongate trough, open at the top, the wide ends of the reamers being oriented along the trough in one longitudinal direction. Arranged within the trough and in the longitudinal direction thereof are elongate, rigid connecting elements. The reamers are attached to the connecting elements in lengthwise intervals between the latter. Elongate, longitudinally oriented parts of the connecting elements are arranged between the reamers, and the lower edges of these parts are close to the bottom wall of the trough. The reamers can substantially be divided along a vertical plane, and the parts mentioned can be continuous and extend between the halves. <IMAGE></p> |
