Selective Boom-Up Lockout for Crane Load Monitoring
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Solution Overview
Problem
Conventional Load Moment Indicator (LMI) systems in cranes uniformly lock out operations when approaching a load limit, leading to unnecessary override habits as operators are required to bypass lockouts frequently, even in situations where raising the boom could alleviate the condition without destabilizing the crane.
Innovation Solution
A method that selectively permits or prohibits crane operations based on the cause of the sensed condition, allowing operators to execute boom up functions without overriding the system when it would efficiently return the crane to safe operational parameters, thereby reducing the likelihood of developing an override habit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LMI system uniformly locks out boom up operations when approaching load limits, then crane safety is improved, but operator efficiency deteriorates due to unnecessary overrides
Solution Approach 1:
The patent applies local quality by differentiating the lockout response based on the specific operational context. Instead of a uniform lockout for all overload conditions, the system identifies specific scenarios (such as when the load is already suspended versus when it is grounded) and applies lockout only where necessary. This allows the system to maintain safety in critical situations while permitting efficient operation in non-critical situations, thereby resolving the contradiction between safety and efficiency.
Solution Approach 2:
The patent implements dynamics by making the lockout function adaptive rather than static. The system continuously monitors operational parameters and dynamically adjusts the lockout behavior based on the current state of the crane and load. This dynamic response allows the system to be restrictive when safety is at risk and permissive when efficiency can be improved, effectively resolving the contradiction between reliability and productivity.
2Reliability
If the LMI system requires override for every locked out operation, then safety control is improved, but operational complexity increases
Solution Approach 1:
The patent applies local quality by making the override requirement context-dependent rather than universal. The system identifies specific operational conditions where override should be required (when safety is compromised) and conditions where it should not (when efficiency can be improved without compromising safety). This selective approach maintains safety control where needed while reducing unnecessary operational complexity.
3Productivity
If the LMI system permits boom up operations in all conditions, then operator efficiency is improved, but crane stability deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by implementing preventive lockout measures before unstable conditions develop. The system monitors operational parameters and proactively prevents boom up operations that would lead to unstable crane configurations. By acting in advance to block potentially harmful operations, the system maintains crane stability while still allowing efficient operation in safe conditions.
Data Source
AI summary
A method is disclosed for controlling a crane which comprises a boom that may be raised or lowered by angular adjustment of the boom about a base portion of the crane. The method prevents operation of the crane in an undesired condition by continuously monitoring operation of the crane, including monitoring at least the position of the boom with respect to the base of the crane. If the crane approaches a limit of its operating range or any operational parameter, its operation will be controlled so as to selectively prohibit or permit a boom raising operation of the crane, depending on the cause of the condition, rather than uniformly prohibit such an operation.