Optical Detection for High-Strength Fiber Rope Discard Criteria

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

High-strength fiber ropes present challenges in predicting their readiness for discard due to the unreliable correlation between rope sheath wear and actual discard condition, as their wear is influenced by various operating conditions and parameters, making it difficult to determine when they should be replaced for safety reasons.

Innovation Solution

The rope sheath is designed with varying daylight absorption and reflection properties to adjust its wear rate according to intended operating conditions, using optical detection means to assess damage and adapt the load cycle counter based on these properties, ensuring the wear rate of the sheath accurately reflects the rope's discardability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If the rope sheath is designed to wear out faster than the rope core to enable visual detection of discard maturity, then the detectability of discard condition is improved, but the reliability of discard prediction deteriorates because sheath wear does not reliably correlate with actual rope discard readiness

Engineering Contradiction:
Improvedetectability of discard conditionVSAvoidreliability of discard prediction
Core Design Contradiction:
Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the optical properties of the rope sheath through coloration. The sheath is colored with specific pigments that alter its optical characteristics, enabling optical detection devices to measure and monitor the sheath's wear state. This parameter change allows for reliable detection of discard maturity by creating a measurable correlation between sheath wear and rope discard readiness through optical property changes.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If multi-colored sheathing is used to make wear visible, then the ease of visual inspection is improved, but the reliability of wear indication deteriorates because the sheath fails suddenly and wear patterns become difficult to interpret

Engineering Contradiction:
Improveease of visual inspectionVSAvoidreliability of wear indication
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies color changes by using specifically colored pigments in the rope sheath that provide reliable visual indication of wear. The coloration system is designed to show progressive wear patterns rather than sudden failure, allowing operators to reliably determine discard maturity through visual inspection. The color changes provide both ease of inspection and reliable indication by creating clear, progressive visual markers of sheath degradation.

Inventive Principle:
Principle #32Color changes

3Measurement precision

If optical detection means are used to monitor rope condition, then the measurement precision of wear state is improved, but the device complexity increases

Engineering Contradiction:
Improveprecision of wear state measurementVSAvoidcomplexity of detection system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies mechanics substitution by replacing complex mechanical inspection systems with optical detection means. Instead of using mechanical devices to measure wear, the system uses optical properties (color, reflectance, absorption) of the sheath to detect wear state. This substitution reduces device complexity while improving measurement precision, as optical detection can non-contactually and accurately measure wear without complex mechanical measurement systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for precise and reliable determination of the discard readiness of high-strength fiber ropes by correlating the wear rate of the sheath with the specific load spectrum and operating conditions, reducing manufacturing complexity and enabling timely replacement, thereby ensuring safety and efficiency.

Implementation Method 1

the rope sheath is designed differently with regard to its solar or daylight absorption and/or reflection in order to adjust the wear resistance or wear rate of the rope sheath

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

the rope sheath is designed differently with regard to its solar or daylight absorption and/or reflection

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3793928B1Device for setting the discarding criteria detection of high-strength fiber ropes, and hoisting gear having such a device
Publication Date: 2023.10.04 LIEBHERR WERK BIBERACH GMBH
  • EP3793928B1 patent drawingFigure 1(a)~1(c)
  • EP3793928B1 patent drawingFigure 2
  • EP3793928B1 patent drawingFigure 3

AI summary

The invention relates to a device for detecting the discarding state of high-strength fiber ropes (I) for various operating conditions, wherein a rope core (II) of the fiber rope is sheathed with a rope sheath (2), which, as intended, wears faster than the cable core, comprising an optical detection unit for detecting the cable surface and/or a load collective counter for detecting the load cycles, which the fiber cable is subjected to. The invention further relates to a hoisting gear such as a crane having such a device. According to the invention, a detection unit for detecting the light absorption coefficient and/or the degree of reflection of the cable sheath, and an adjustment device for adjusting the algorithm, with the aid of which the discard criteria is determined subject to the detected light absorption coefficient and/or the detected degree of reflection, is provided.