| 摘要 |
<p>The lifting hoist for a marine platform has a derrick on a heel bearing, held by topping lifts running to posts, free to swing and pass between these, carrying a runner. At its head the derrick has a topping-lift ring, separately rotatable through 360 deg. and possibly also a running ring. Both have fastening-eyes. There are three posts (1,2,3) at the apices of an imaginary horizontal triangle (6) around the heel bearing (5), with a topping-lift from each (11,12,13) tothe ring. The runner ring may slide around the (sleeve-form) head end of this or be fixed to the derrick above it.</p> |
