| 摘要 |
A mechanism for reversing the direction of rotation in a drilling apparatus comprising a feeding beam (1) and a drilling machine (3) supported by the beam for longitudinal movement back and forth along the beam in a drilling direction (A) and an opposite return direction (B) by a feeding mechanism (4). The drilling machine is provided with a pressure medium driven rotating device (9) for rotating a drilling rod and with a reversing valve (13) connected to the pressure medium system of the rotating device. The reversing valve is provided with a spindle rotatable between two positions in which the rotating device rotates the drilling rod in opposite directions. The reversing mechanism comprises two actuating elements (24,27) rotatable with respect to each other. One element (24) is in rotational engagement with the spindle and is moved axially together with the spindle at least at the end of the return direction of the drilling machine. The other element (27) is arranged to maintain non-rotating and stationary by a fixed stop (31) in the feeding beam at the end of the return direction but to rotate and move axially with respect to the one element at the beginning of the drilling direction. The actuating elements are coupled to each other by members (28,29) which force said one element to rotate with respect to the other element when the elements move axially with respect to each other and thereby to rotate also the spindle to a position causing a reversal of the direction of rotation of the rotating device. |
