| 摘要 |
PCT No. PCT/NO87/00042 Sec. 371 Date Mar. 31, 1988 Sec. 102(e) Date Mar. 31, 1988 PCT Filed May 29, 1987 PCT Pub. No. WO87/07673 PCT Pub. Date Dec. 17, 1987.Arrangement in a hoisting device, especially for a derrick (1) comprising two parallel vertical derrick components (3, 4), each of which carrying a rack rail (10) along which the hoisting device (6) can move vertically by means of a driving means (6a+B, 6b) which is arranged on each derrick component (3, 4) and which via gear wheels (8, 9) engages the rack rails (10), the hoisting device (6) comprising a transverse supporting member (18) extending between the two driving means (6a+B, 6b). In order to avoid breakdown of the hoisting device and associated structural parts, the invention provides a transverse supporting member (18) which in the area of each driving means (6a, 6b) comprises a pivotable bearing (30, 31) which during irregular skew loading on the two driving means (6a, 6b) allows for a relatively largely inclined position of the supporting member (18), the supporting member (18) in the area of one of the driving means (6a) also comprising a bracing means (34) which during normal parallel operation of the driving means (6a, 6b) stiffens the supporting member, but which during irregular operation is brought to collapse in order to allow the bearing arrangement (30, 31) to be effective for rendering the supporting member (18) an inclined position which prevents breakdown of machinery and associated structural members.
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