Hoist Chain Elongation Monitoring Using Link Timing Signals
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Solution Overview
Problem
Existing methods for monitoring hoist chain wear require interruption of operation and are prone to sensor failure due to movable components and the need for markers, lacking a simple and cost-effective solution for continuous condition monitoring.
Innovation Solution
A method using a single sensor to detect the presence and absence of chain links, determining time intervals, and comparing sums of these intervals to determine elongation, allowing continuous monitoring without interruption, and optionally using a second sensor to detect sprocket teeth for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodical inspections are carried out to evaluate chain wear, then chain safety is improved, but operational continuity deteriorates due to interruption of hoist operation
Solution Approach 1:
The patent implements continuous condition monitoring of the hoist chain during operation using sensors that detect chain link presence and absence. The evaluation unit continuously processes sensor signals to determine chain elongation, eliminating the need to stop the chain hoist for inspections. This maintains productive action while ensuring chain safety through real-time monitoring.
2Productivity
If movable sensors are used for continuous monitoring, then operational continuity is improved, but system reliability deteriorates due to sensor failure risk
Solution Approach 1:
Instead of moving the sensor along the chain, the patent inverts the approach by keeping the sensor stationary and allowing the chain to move past it. The sensor remains fixed at a monitoring location while the moving chain continuously passes through the sensor's detection field, enabling continuous monitoring without moving components in the sensor assembly.
3Measurement precision
If markers are applied to the chain for wear detection, then measurement precision is improved, but device complexity deteriorates due to additional components
Solution Approach 1:
The patent utilizes the chain's own structural features (chain links and their natural spacing) as the measurement reference, eliminating the need for externally applied markers. The sensor detects the presence and absence of chain links, and the evaluation unit calculates chain elongation based on the time intervals between detected links, using the chain's inherent geometry for self-monitoring.
4Measurement precision
If multiple sensors are used for monitoring, then measurement precision is improved, but device complexity deteriorates due to additional sensors and support structures
Solution Approach 1:
The patent segments the measurement process into two distinct time intervals using a single sensor: the first time interval measures the presence of a chain link, and the second time interval measures the absence of a chain link. By evaluating these segmented time intervals separately and comparing them, the system achieves precise wear detection without requiring multiple sensors or complex support structures.
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
Enables continuous, uninterrupted monitoring of hoist chain wear, reducing sensor failure risks and operational costs, while maintaining monitoring accuracy through chain speed normalization and sensitivity adjustments.
Implementation Method 1
both inductive sensors (9a, 9b) are arranged and configured to detect a presence and an absence of chain links (3a)
Data Source
AI summary
A method and system for continuous condition monitoring of a hoist chain implementation of the following steps:—detecting with at least one sensor a presence/absence of chain links and/or of teeth of a chain sprocket,—determining with an evaluation unit, using a signal obtained from the sensor(s), time intervals reflecting the presence/absence, and—determining with the evaluation unit sums of the time intervals,—determining with the evaluation unit a chain speed, and—comparing with the evaluation unit the first sum with the second sum in order to determine an elongation of the hoist chain, wherein each time interval was determined at the same chain speed.