| 摘要 |
<p>An elevating unit (10) for a jack-up rig (11) provides a pinion gear (23) that rotates upon a support frame for engaging a toothed rack of each leg (14) of the jack-up rig. Each pinion gear (23) is mounted on a gear shaft (28) that extends in opposite directions from a plane of rotation of the gear. First (29) and second (30) roller bearings are mounted upon the frame for supporting the pinion gear at first (35) and second (36) pinion gear shaft end portions. On one shaft end portion, a planetary gear box (27) engages the shaft, the gear box being motor driven. On the opposite side of the shaft end portion a brake hub (32) is attached to the pinion gear shaft and carries a brake drum (33). A brake band (39) extends about the drum, the band being operable to frictionally engage the brake drum to retard movement of the drum, hub and pinion gear shaft relative to the frame.</p> |
