Method and device for detecting crack formation in a hoisting member
First Claim
1. A method for detecting crack formation in a hoisting member, comprising the steps of:
- measuring a stress under load at least at two points of the hoisting member,comparing the measured stresses, andgenerating a warning signal when the measured stresses differ too much from each other,wherein the stress at each point is measured by measuring a corresponding deformation between that point and another point, andwherein a first deformation is measured between a relatively lightly loaded point of the hoisting member and another point, and a second deformation is measured between a relatively heavily loaded point of the hoisting member and another point.
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Accused Products
Abstract
The invention relates to a method for detecting crack formation in a hoisting member, comprising the steps of measuring a stress under load at two points of the hoisting member, comparing the measured stresses and generating a warning signal when the measured stresses differ too much from each other.
The invention also relates to a device for detecting crack formation in a hoisting member, comprising means arranged at two points of the hoisting member for measuring a stress under load, means connected to the measuring means for comparing the measured stresses, and means connected to the comparing means for generating a warning signal when the measured stresses differ too much from each other.
Finally, the invention relates to a hoisting frame, comprising a number of hoisting members which are mounted thereon close to its corners, and crack detection devices connected thereto.
3 Citations
19 Claims
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1. A method for detecting crack formation in a hoisting member, comprising the steps of:
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measuring a stress under load at least at two points of the hoisting member, comparing the measured stresses, and generating a warning signal when the measured stresses differ too much from each other, wherein the stress at each point is measured by measuring a corresponding deformation between that point and another point, and wherein a first deformation is measured between a relatively lightly loaded point of the hoisting member and another point, and a second deformation is measured between a relatively heavily loaded point of the hoisting member and another point. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A crack detection device for detecting crack formation in a hoisting member, comprising:
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at least two measurement elements, each of which is arranged at a point of the hoisting member for allowing measurement of a stress under load, a comparator connected to the measuring elements for comparing the measured stresses, and a warning signal generator connected to the comparator for generating a warning signal when the measured stresses differ too much from each other, wherein each of the measurement elements is adapted to allow measurement of a deformation between the point at which the measurement element is arranged and another point, said deformation corresponding to the stress, and wherein the measurement elements comprises a first measurement element arranged at a relatively lightly loaded point of the hoisting member and a second measurement element arranged at a relatively heavily loaded point of the hoisting member. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A hoisting frame assembly, comprising:
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a hoisting frame having corners, a plurality of hoisting members which are mounted on the hoisting frame close to the corners of the hoisting frame, and crack detection devices connected to the hoisting members for detecting crack formation in the hoisting members, each crack detection device comprising; at least two measurement elements, each of which is arranged at a point of one of the hoisting members for measuring a stress under load at the point at which it is arranged, a comparator connected to the measurement elements for comparing the measured stresses, and a warning signal generator connected to the comparator for generating a warning signal when the measured stresses differ too much from each other, wherein each of the measurement elements is adapted to allow measurement of a deformation between the point at which the measurement element is arranged and another point, said deformation corresponding to the stress, and wherein the measurement elements comprises a first measurement element arranged at a relatively lightly loaded point of the hoisting member and a second measurement element arranged at a relatively heavily loaded point of the hoisting member.
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Specification