| 摘要 |
The invention relates to a travelling centralizer arrangement in a rock drill (2), comprising a travelling centralizer (5) movable along the feeding beam (1) during the drilling. The travelling centralizer (5) of the arrangement comprises two jaw halves (12a, 12b) mounted in a carriage (8) provided for the travelling centralizer so as to be pivoted about journals (13a, 13b) parallel to the feeding beam (1). Each jaw half (12a, 12b) comprises a wheel (9a, 9b) moving along the guideways (10) of the feeding beam (1) and keeping the jaw halves (12, 12b) pressed against each other during normal drilling so that jaws (14a, 14b) form a drill rod centralizer concentric with the drill rod (4). The guideways (10) comprise at the forward end of the feeding beam (1) a portion (L) which extends downward from the straight guideway portion. When the travelling centralizer reaches this downwardly extending guideway portion, the wheels (9a, 9b) are displaced downward along the surface of the guideways, so that the jaw halves (12a, 12b) are pivoted about the journals (13a, 13b), thus drawing the jaws (14a, 14b) of the travelling centralizer apart from each other so that the chuck (3) is able to pass therethrough. |
