How does this crane work ?
Sorry the photo is blurry - the light was failing. It's on a dredger. The top right diagonal spar looks like a rigid tube, while there are cables diagonally across. Seems to me that if the cables are tensioned, the main jib goes up and the lifting jib goes down - I can't see how the crane lifts anything.
- WhomeLv 75 years agoFavorite Answer
Your four bar analysis is correct. There will be a lifting winch at the base of the main boom. The cable crosses pulleys at the joint between main boom and jib and at the left end of the jib. Allows for a fairly good range of extensions without extreme changes in the angle of the main boom. Good for lifting moderate loads about a wide area with obstructions about the base of the crane.
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