摘要 |
A hoist for positioning a load (40) includes a plurality of lift cylinders (15), a plurality of position sensors, a plurality of electronically controlled valves, a user input device (22), and a hoist controller (20). Each of the hydraulic hoist cylinders is coupled at one end to the hoist and at an opposite end to the load at a lifting point (45). Each of the position sensors is associated with one of the hoist cylinders and operable to provide position data for the associated hoist cylinder. The electronically controlled valves are hydraulically coupled to the hoist cylinders for extending and retracting the associated hoist cylinders. The user input device is operable by a user to specify load data. The hoist controller is operable to receive the load data from the input device and the position data from the position sensors and in response thereto to control the electronically controlled valves so as to position the load according to the load data.
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