Elevator Tension Member Inspection Using Conductive Wrap
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Solution Overview
Problem
Conventional elevator systems face challenges in accurately and reliably monitoring the wear and failure of tension members due to direct electrical connections causing point contact and resulting in inaccurate and non-repeatable resistance measurements.
Innovation Solution
An electrical inspection system with a copper wrap secured to the load bearing member using a tie or washer, ensuring continuous contact around the circumference to provide accurate and repeatable measurements of electrical resistance, indicating wear and remaining service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If circuit leads are connected directly to the rope or cord, then the inspection system can monitor electrical resistance, but the direct connection results in point contact that causes inaccurate and non-repeatable measurements
Solution Approach 1:
The patent introduces a wrap as an intermediary component between the circuit leads and the rope/cord. The wrap provides a distributed contact surface that distributes the electrical connection across multiple points on the rope or cord, eliminating point contact issues. This intermediary structure ensures consistent and repeatable electrical resistance measurements by providing a stable, distributed contact interface rather than a single point of contact.
2Measurement precision
If a wrap is secured to the load bearing member, then continuous contact around the circumference is ensured for accurate measurements, but the device complexity increases
Solution Approach 1:
The patent employs a wrap made from flexible conductive material that can be secured around the circumference of the load bearing member. This flexible shell approach allows the wrap to conform to the rope or cord surface while maintaining continuous electrical contact. The simplicity of using a flexible wrap rather than a complex rigid connector structure minimizes device complexity while achieving the goal of continuous contact for accurate measurements.
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 system ensures accurate and repeatable electrical resistance measurements, enabling effective monitoring of tension member wear and timely intervention, improving the reliability and safety of elevator operations.
Implementation Method 1
the electrical resistance of the rope or cord is proportional to its cross-sectional area, changes in electrical resistance can be correlated to reduction in cross-sectional area of the rope or cord
Implementation Method 2
A wrap 38 extending entirely around a circumference of the rope 16... The material is chosen to be low resistive so that the wrap 38 will not effect the magnitude of the resistance measurement
Data Source
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Figure 1C
AI summary
An electrical inspection system for an elevator load bearing member includes an electrically conductive, low resistance wrap located at the load bearing member, contacting the load bearing member around a circumference of the load bearing member. An inspection unit is configured to apply an electrical current through the load bearing member and determine an electrical resistance of the load bearing member, and is electrically connected to the load bearing member at the wrap to distribute electrical current uniformly therethrough. A method of determining an electrical resistance of a load bearing member of an elevator system includes applying an electrically conductive low electrical resistance wrap entirely around a circumference of the load bearing member. An inspection unit is connected to the load bearing member at the wrap. An electrical current is applied through the wrap into the load bearing member to determine an electrical resistance of the load bearing member.