| 摘要 |
<p>A locking device in a finger board in a derrick is arranged in the form of movable locking pieces (16) distributed along finger board slots (12), and serve to retain, but under influence allow withdrawal/insertion of drill pipe stands (10) from/into the slots (12). Each locking piece (16) has an actuator in the form of a piston and cylinder (28, 28a) arranged thereto in order to be pivoted between an active position within the slot (12) in the path of motion of pipes, and an idle position, in which the locking piece (16) is essentially outside the slot (12) and does not prevent pipe movement in any direction. To allow several locking pieces (16) to be operated in step, by the same control signal, each locking piece (16) has two stops (18a, 20a) and is pivotable about a vertical axis (22) located equidistantly from the two stops (18a, 20a). Through pivoting, one stop (18a) may thereby be positioned into the finger board slot (12), whereas the other stop (20a) is outside the slot (12). In a second pivoting position, the second stop (20a) may then be positioned in the slot (12), whereas the first-mentioned stop (18a) is outside the slot (12).</p> |
