| 摘要 |
The winches of a luffing crane having two individually operated hoisting cables depending from different longitudinal sections of the boom are deenergized by an overload protection mechanism when the torque exerted during luffing by a single load suspended from both cables exceeds a value consistent with the stability of the crane. The mechanism which employs only mechanical elements derives signals from the stresses transmitted by the loaded cables to the two winches, weights the signals in accordance with the different spacing of the dependent cable ends, adds the weighted signals, and compares the sum so obtained with a signal derived from the angular boom position and a curve of maximum permissible loads arrived at from design parameters of the crane and the spacing of the cable ends.
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