| 摘要 |
A drill (1) for drilling crossties, particularly for use in the railroad sector, comprising a protective enclosure which is formed by a movable portion (11) and by a fixed portion (10) and is suitable to completely cover a chuck (5) of a drill (1) and a drilling bit (6) coupled to the chuck; sliding means (15,16) which allow the sliding of the movable portion (11) with respect to the fixed portion (10) when the movable portion (11) is placed at an area to be drilled and at the beginning of the drilling operation; and contrast means (17,18) adapted to contrast the sliding of the movable portion (11) with respect to the fixed portion (10) and suitable to be loaded by the penetration of the drilling bit (6) and, at the end of the drilling operation, to be released for the quick disengagement of the bit (6) from a hole formed during the drilling operation. <IMAGE> |
