Crane load inidicating arrangement
First Claim
1. A load indicating arrangement for use with a crane or other lifting apparatus having a pivotally mounted telescoping boom comprising, boom supporting means, means for producing a first output signal representative of the total turning moment of the boom about its pivot in supporting a load, said first output signal producing means including transducer means for producing an output signal which is a function of the reaction sustained by the boom supporting means in supporting the boom and any bad suspended therefrom and angle sensing means for modifying said output signal in accordance with the sine of the angle included between the boom supporting means and the boom, means for producing a second output signal representative of the turning moment of the boom about its pivot due to the weight of the boom alone, means for combining said first and second output signals to produce a third output signal which is the algebraic difference between said first and second output signals and which is thus representative of the turning moment due only to the load, means for deriving a load radius output signal representative of the horizontal distance between the boom pivot point and the load and independent of the weight of the boom, a law generator unit for each mode of operation of the crane, a first one of the law generator units including means responsive to said load radius output signal for producing a fourth output signal which varies with the load radius and is representative of the maximum safe load moment for the crane in the appertaining mode of operation involving radius related duties and for the existing load radius, and means for comparing said fourth output signal with said third output signal to provide an indication of available lifting capacity.
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Accused Products
Abstract
A crane safe load indicator combines signals representing the total loaded boom turning moment and the turning moment of the boom alone to derive a third signal representing the turning moment of the load alone. The third signal is compared with a signal representing the crane'"'"'s maximum safe load moment to indicate available lifting capacity.
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Citations
20 Claims
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1. A load indicating arrangement for use with a crane or other lifting apparatus having a pivotally mounted telescoping boom comprising, boom supporting means, means for producing a first output signal representative of the total turning moment of the boom about its pivot in supporting a load, said first output signal producing means including transducer means for producing an output signal which is a function of the reaction sustained by the boom supporting means in supporting the boom and any bad suspended therefrom and angle sensing means for modifying said output signal in accordance with the sine of the angle included between the boom supporting means and the boom, means for producing a second output signal representative of the turning moment of the boom about its pivot due to the weight of the boom alone, means for combining said first and second output signals to produce a third output signal which is the algebraic difference between said first and second output signals and which is thus representative of the turning moment due only to the load, means for deriving a load radius output signal representative of the horizontal distance between the boom pivot point and the load and independent of the weight of the boom, a law generator unit for each mode of operation of the crane, a first one of the law generator units including means responsive to said load radius output signal for producing a fourth output signal which varies with the load radius and is representative of the maximum safe load moment for the crane in the appertaining mode of operation involving radius related duties and for the existing load radius, and means for comparing said fourth output signal with said third output signal to provide an indication of available lifting capacity.
- 2. A load indicating arrangement for use with a crane or other lifting apparatus having a pivotally mounted telescoping boom comprising, means for producing a first output signal representative of the total turning moment of the boom about its pivot in supporting a load, means for producing a second output signal representative of the turning moment of the boom about its pivot due to the weight of the boom alone, means for combining said first and second output signals to produce a third output signal which is the algebraic difference between said first and second output signals and which is thus representative of the turning moment due only to the load, a law generator unit for each mode of operation of the crane, a first one of the law generator units including means for producing a fourth output signal which varies with the load radius and is representative of the maximum safe load moment for the crane in the appertaining mode of operation and for the existing load radius, means for comparing said fourth output signal with said third output signal to provide an indication of available capacity, a second one of said law generator units for angle related duties including means for producing a further fourth output signal which in this case is representative of the maximum safe hook load for the crane in the appertaining angle related mode of operation and for the existing luff angle, means for producing a fifth output signal which is representative of the weight of the load, and means for comparing said fifth output signal with said further fourth output signal to provide an indication of the actual crane hook load relative to the maximum safe hook load.
- 14. A load indicating system for a crane having a pivoted boom comprising, means for producing a first output signal representing the total turning moment of the boom and its load about the boom pivot, means for producing second and third output signals representing the length of the boom and the boom luff angle, respectively, means responsive to said second and third output signals for producing a fourth output signal representing the horizontal distance between the load and the boom pivot point, means responsive to the second output signal for producing a fifth output signal representing the weight of the boom alone acting through its center of gravity, law generator means for selectively producing an output signal representing the maximum safe load moment of the crane or the maximum safe hook load for the existing mode of crane operation, and computing means responsive to said first, second, third, fourth, fifth and law generator output signals for deriving output indicating signals representing the available crane lifting capacity and the weight of the load.
Specification