Abstract: The crane comprises a generally horizontal boom or other supporting structure having at least one rail thereon, a trolley having a reversible drive for moving the trolley in either direction along the rail, a wire rope hoist suspended from the trolley, and a load carrying device suspended from the hoist for selectively grasping and releasing a freight container or some other load. The crane has a control system which causes the trolley drive to stop the trolley momentarily at a first stopping position. Due to the control system, the drive then restarts the trolley and stops it at a second stopping position directly over a transfer position where the load is to be delivered and released. If the load is a freight container, the transfer position may be directly over a cell of a container ship. The control system includes an encoder for determining the length of the pendulum comprising the trolley, the hoist, the load carrying device and the load.

Abstract: The crane comprises a horizontal boom or other support structure having at least one rail thereon, a trolley along the rail, a rope hoist, and a load carrying device. A control system causes the driven trolley to be stopped momentarily at a first position. The control system then restarts the trolley and stops it at a second position directly over a transfer position. The control system includes an encoder for determining the total length of the pendulum of the crane and the load. The stopping of the trolley at the first position causes the load to swing forwardly into the first quarter of a pendulum cycle. The control system includes means for adjusting the distance between the first and second positions to correspond with the horizontal component traveled by the load during the first quarter of the pendulum cycle whereby the load is stopped without any residual swinging movements.

Abstract: An endless loop tractor drive mechanism has equally spaced pushers meshing with a bucket train where its filled circular buckets are traveling along a substantially straight ascending path to a dumping support wheel. Wire rope cables or other flexible tension elements extend between the buckets. The pushers have drive rollers for pushing the buckets, and additional rollers for guiding the cables. Additional support wheels guide the bucket train along a catenary loading span where the buckets are dragged through bulk material to fill the buckets. At least two pushers engage at least two successive buckets at all times, to distribute and share the lifting load among two or more buckets. Due to the straight ascending path, the cables are not flexed when the lifting load is applied. Thus, the combination of high tensile stresses and high cable flexure is avoided. Wear and tear on the cables are thereby minimized. Fraying and breakage of the cables are no longer problems.