| 摘要 |
The guide (5) comprises a frame (6) mountable on the drill feed beam (3) two guide elements (9, 10) mounted on the frame (6) and locatable on opposite sides of a drill rod (13) to form a guide opening (12) for the drill rod (13), the elements (9, 10) being spaced apart in the direction of the guide axis (A) to form between them a free through slot (14) transverse to the guide axis (A) and having a width (L) greater than the width (Hj) of the drill coupling sleeve (15). The elements (9, 10) are returnably pivotable by means (16) engaged therewith, around a pivot shaft perpendicular to the guide axis (A) from the guiding position shown to a releasing position in which the transverse slot (14) becomes aligned with the axis (A) so permitting passage of the coupling sleeve (15) therethrough. The pivoting means (16) is mounted in use in the path of drill member (2), and is displaceable in the direction of guide axis (A), so that member (2) actuates the pivoting means (16) to pivot the elements (9, 10) to the releasing position as member (2) approaches the guide (5) during drilling. <IMAGE> |
