| 摘要 |
<p>Lift comprises a number of columns and a platform guided by the columns and moved vertically relatively to them. The platform may be a pontoon and it is linked to the columns by a lifting mechanism. This consists of climbing bars arranged between the head of each column and the platform to which they are fixed. Jack assemblies hang from crossheads on the top of each column, and in them are >=2 locking bolts which can be displaced horizontally and engage in turns in recesses in the climbing bars. The climbing bars are rigid and are enclosed with a little play by hinged frames suspended from the crossheads. Inside the frames there are bolts which grip the climbing bars on opposite sides. From the first frame on each side of the climbing bar, jacks hang, and a similar frame is hinged below these; one frame being attached to the jack cylinder and the other to the piston rod. Arrangement facilitates lowering and lifting of heavy loads in water without the difficulty of the jacking and bolting mechanism being submerged, and is partic. applicable to the floating of large caissons constructed on shore and rolled on to the platform for lowering into the water.</p> |
