Elevator Tensile Element Integrity Check via Pulse Reflection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing non-visual inspection methods for elevator load-bearing members, such as resistance-based systems, are not sensitive enough to detect damage in tensile elements due to variations caused by factors like temperature, load, and winding conditions, leading to potential false alarms and reduced reliability.
Innovation Solution
A method using a time domain reflectometer (TDR) to send pulses through tensile elements and compare the feedback, allowing for the detection of damage by analyzing differences in feedback pulses between elements, which is less affected by external factors like winding and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If resistance-based inspection is used to check tensile elements, then non-visual inspection capability is provided, but measurement precision deteriorates due to sensitivity to boundary conditions such as temperature, load, and winding
Solution Approach 1:
The patent introduces an intermediary measurement approach by using time-domain reflectometry to measure the electrical characteristics of tensile elements. Instead of directly measuring resistance which is sensitive to boundary conditions, the system sends electrical pulses through the tensile elements and analyzes the reflected signals. This intermediary method (measuring pulse reflection timing and characteristics) provides a more accurate indicator of physical damage while being less sensitive to temperature, load, and winding variations.
2Ease of operation
If absolute resistance measurement is used, then inspection simplicity is maintained, but reliability deteriorates due to false alarms from boundary condition variations
Solution Approach 1:
The system uses pulse reflection characteristics as an intermediary measure that is less directly influenced by boundary conditions. By measuring the time of flight and reflection patterns of electrical pulses rather than absolute resistance, the method maintains operational simplicity while significantly reducing false alarms caused by temperature, load, and winding variations.
Solution Approach 2:
The patent implements preliminary calibration by comparing the pulse reflection characteristics of multiple tensile elements against each other and against reference values before actual inspection. This preliminary comparison establishes baseline expectations for each element under normal conditions, allowing the system to distinguish between normal variations due to boundary conditions and actual damage indicators.
3Ease of manufacture
If resistance-based inspection is used, then existing electrical measurement infrastructure can be utilized, but measurement precision deteriorates because small damages cause only small resistance variations
Solution Approach 1:
The patent employs pulse reflection timing and signal characteristics as an intermediary measurement that amplifies the detectability of small damages. When a tensile element has even minor damage, it creates impedance discontinuities that reflect electrical pulses. By measuring the timing and characteristics of these reflections rather than small resistance changes, the system maintains compatibility with existing electrical infrastructure while dramatically improving sensitivity to small damages.
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 method provides a more reliable and sensitive means of detecting damage in elevator tensile elements, reducing the risk of false alarms and improving the accuracy of condition assessment by comparing feedback from multiple elements.
Implementation Method 1
Each said tensile element is made of electrically conductive material
Data Source
AI summary
A method for checking the integrity of a load bearing member of an elevator including tensile elements encapsulated in a case includes the steps of launching a source pulse through tensile elements of said load bearing member and comparing the feedback of said tensile elements with a comparator; tensile elements can be bridged to avoid a blind zone.