US 12,617,657 B2 · Method for protecting a lifting member against an overload and device implementing this method

Abstract

A method for protecting a lifting member against an overload is described. The lifting member includes a lifting drum over which a cable is wound at the end of which a load is fixed. The lifting drum is mechanically connected to an electric motor capable of ensuring its rotation. The mechanical connection includes a clutch or equivalent device, has at least two distinct operating thresholds: a first threshold, the exceeding of which generates the freewheel operation of the lifting drum with respect to the kinematic chain coming from the electric motor, and a second threshold, of value greater than that corresponding to the nominal load of the lifting member, but of value less than that of the first threshold, generating the braking of the rotation of the lifting drum, and an attempt to progressively stop said rotation of the drum.

Claims13

Dependent claims

A method for protecting a lifting member against an overload, the lifting member comprising a lifting drum on which a cable is wound, cable at the end of which a load is fixed, said lifting drum being mechanically connected to an electric motor capable of ensuring its rotation, the mechanical connection comprising a clutch or equivalent device, wherein said method comprises at least two distinct operating thresholds:

a first threshold, the exceeding of which generates a freewheel operation of the lifting drum with respect to a kinematic chain coming from the electric motor;
a second threshold, of a value greater than that corresponding to a nominal load of the lifting member, but of a value less than that of the first threshold, generating a braking of the rotation of the lifting drum and an attempt to progressively stop said rotation of the lifting drum.

A device for protecting a lifting member against an overload, said lifting member comprising:

a lifting drum on which a lifting cable is wound, cable at the end of which a load is fixed;
an electric motor provided with a rotary shaft capable of ensuring a rotation of the lifting drum;
a clutch or equivalent device mounted on a mechanical connection connecting the electric motor to the lifting drum and capable of uncoupling the motor from the drum;
wherein the clutch or equivalent device is provided with elements capable of ensuring a free rotation of the lifting drum with respect to the rotary shaft of the motor as soon as a torque exerted by the cable on said lifting drum is greater than a predetermined threshold value, called first threshold;
wherein the protection device also comprises braking means of the rotation of the lifting drum, the maximum braking capacities of which constitute a second threshold, of a value greater than that corresponding to the nominal load of the lifting member, but of a value less than that of the first threshold.

2 more elements

Dependencies are inferred from the claim text.

Method for protecting a lifting member against an overload and device implementing this method

Life of this patent

Method for protecting a lifting member against an overload and device implementing this method

Life of this patent

Abstract

Claims13