Importance

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Abstract

Method in a stacker crane for weighing a load, which comprises a lifting carriage, motor means which are arranged to lift and lower the lifting carriage, a lifting member that transmits tensile stress and on the support of which the lifting carriage is suspended for movement and on which the motor means exert a tensile effect for the movement of the lifting carriage, and first sensor means which are arranged to determine the position of the lifting carriage and generate a first signal, control means, second sensor means which are arranged to generate a second signal that is proportional to the amount of the lifting member that is fed via the motor means. In the method the elongation of the lifting member is determined that is caused by the load positioned in the lifting carriage, said elongation being proportional to the difference of the first and second signal when the position of the lifting carriage is also determined on the basis of the second signal, and the weight of the load is determined by means of a calculation algorithm, said weight corresponding to the produced elongation. In the calculation the stretching length of the lifting member and the predetermined spring constant of the lifting member that describes the elongation of the lifting member as a function of the loading and the stretching length, are taken into account in addition to the elongation.

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First Claim