Anti-two-block sensing device for crane hoisting lines

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Solution Overview

Problem

Existing anti-two-block sensing devices in crane systems are prone to maintenance issues and may fail to effectively prevent two-blocking conditions due to the use of seals, springs, and precision sliding components, which can lead to interference and failure in hoisting operations.

Innovation Solution

An anti-two-block sensing device is designed with a low-maintenance chandelier that includes a trigger assembly and proximity sensors to detect the approach of the lower block toward the upper block, avoiding contact by triggering alerts or preventive measures, and is devoid of seals, springs, and precision sliding components, ensuring reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional anti-two-block sensing devices use seals, springs, and precision sliding components, then they can detect the approach of the lower block, but they are prone to maintenance issues and may fail due to interference and wear

Engineering Contradiction:
Improvereliability of detection systemVSAvoidcomplexity of sensing device
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes seals, springs, and precision sliding components from the sensing device, extracting only the essential triggering mechanism that relies on the natural tension and movement of the hoisting line itself to activate the detection system

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hoisting line serves its dual function of both lifting the load and activating the anti-two-block detection system through its own tension and movement, eliminating the need for separate complex mechanical components

Inventive Principle:
Principle #25Self-service

2Ease of operation

If existing sensing devices use precision sliding components and springs, then they can provide detection capability, but they require frequent maintenance and may fail during operation

Engineering Contradiction:
Improveease of maintenanceVSAvoidoperational reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent eliminates springs, seals, and precision sliding components that require maintenance, retaining only the essential trigger mechanism that uses the hoisting line's natural properties

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sensing device is designed with simple, replaceable components that can be easily swapped if needed, rather than attempting to make complex components last indefinitely through maintenance

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If traditional sensing devices are used, then they can detect two-blocking conditions, but they may fail to effectively prevent two-blocking due to component failure

Engineering Contradiction:
Improveeffectiveness of preventionVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent strips away complex mechanical components (seals, springs, sliding parts) and retains only the essential trigger mechanism that uses the hoisting line's tension to activate detection

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex mechanical sensing systems with a simpler trigger-based mechanism that relies on the natural physical properties of the hoisting line and block movement

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

The solution effectively prevents two-blocking conditions by providing a reliable and low-maintenance detection system that reduces the risk of hoisting line failure and disconnection, enhancing the safety and efficiency of crane operations.

Implementation Method 1

A sensing cap having proximity sensors or other detectors can be mounted on the chandelier for detecting the approach of the lower block toward the upper block

Methodology Applied
Scientific EffectProximity sensing:

Data Source

PatentEP3408213B1Anti-two-block sensing systems
Publication Date: 2022.08.31 KEPPEL LETOURNEAU USA INC
  • EP3408213B1 patent drawingFigure 1
  • EP3408213B1 patent drawingFigure 2~3
  • EP3408213B1 patent drawingFigure 4~5

AI summary

Various hoisting systems with anti-two-block sensing devices are provided. In one embodiment, an apparatus includes a crane having a hoisting line and an anti- two-block sensing device installed about the hoisting line. The anti-two-block sensing device includes an upper chandelier, a lower trigger assembly suspended from the upper chandelier, and a detector positioned to detect movement of the lower trigger assembly with respect to the upper chandelier. The lower trigger assembly can include two plates each having a hoisting line aperture and a slot that allows transverse installation of the plate about the hoisting line. Further, the two plates can be positioned such that their slots are offset from one another and the plates cooperate to fully surround the hoisting line. Additional systems, devices, and methods are also disclosed.