Capacitive Tension Sensor for Elevator Rope Monitoring
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Solution Overview
Problem
Current tension member tension monitoring solutions for elevators are costly, require customization for each elevator, and are difficult to install due to space constraints, leading to inefficient and inaccurate manual monitoring.
Innovation Solution
A compact tension member tension monitoring arrangement using capacitive pressure sensors attached to tension member terminations and connected to a control unit, allowing for easy installation and accurate measurement of tension forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If donut type-sensors or rope bending-based sensors are used to monitor tension member tension, then tension measurement capability is improved, but material cost and installation complexity increase due to customization requirements and space constraints
Solution Approach 1:
The sensor is divided into separate modular components: a body portion with mounting features and a sensor element portion that can be independently positioned. This segmentation allows each component to be optimized separately and assembled in space-constrained environments without requiring complete customization of the entire sensor assembly.
Solution Approach 2:
The sensor design allows the sensor element to be positioned within or adjacent to the termination assembly structure itself, nesting the measurement function within the existing structural framework. This eliminates the need for separate donut-type sensors that require additional space around the rope termination.
2Measurement precision
If individual sensor elements are installed one by one on each tension member, then accurate individual tension monitoring is achieved, but installation time and labor cost increase
Solution Approach 1:
Multiple sensor elements are combined into a single integrated sensor assembly that can be installed as one unit. The sensor body provides a common mounting structure that holds multiple sensing elements, allowing simultaneous monitoring of multiple tension members through a single installation operation rather than installing separate sensors on each member individually.
Solution Approach 2:
The sensor design incorporates universal mounting features that can accommodate different termination types and configurations. The sensor body includes mounting surfaces and attachment mechanisms that work with various elevator termination designs, eliminating the need for custom sensor variants for different installation scenarios.
3Ease of manufacture
If termination springs are used for tension monitoring, then installation simplicity is improved, but measurement accuracy deteriorates due to wide tolerance range of spring movements
Solution Approach 1:
The invention introduces a dedicated sensor element as an intermediary between the tension member termination and the measurement system. This sensor element directly measures the tension force through controlled mechanical interaction with the termination, providing precise quantitative data without relying on the ambiguous movement of termination springs.
Solution Approach 2:
The invention replaces the mechanical spring-based indication system with an electronic sensor system that provides direct electrical signals proportional to tension. This substitution transforms the measurement from qualitative visual inspection of spring movement to quantitative electronic measurement, dramatically improving accuracy while maintaining ease of installation.
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 reliable and efficient monitoring of tension member tensions, allowing for early detection of potential issues, unmanned maintenance checks, and cost-effective installation, thereby extending the lifespan of elevator components.
Implementation Method 1
at least one capacitive pressure sensor arranged in connection with a tension member termination and a control unit connected to the at least one sensor. The at least one sensor is configured to sense the tension member forces of the individual tension members
Data Source
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AI summary
A tension member tension monitoring arrangement and method for measuring tension member tension of elevator tension members of a bundle of tension members, the elevator comprising an elevator car (102, 202, 302) suspended by the tension members, such as ropes or belts, of the bundle of tension members (103, 203, 303), a termination (401) at one end of a tension member and a mounting plate (403) for attaching the termination relative to the hoistway (101, 301), counterweight and/or the elevator car (102, 202, 302). The tension member tension monitoring arrangement comprises at least one capacitive pressure sensor (120, 220, 320, 420, 520) arranged in connection with a tension member termination (401). The arrangement further comprises a control unit (702) connected to the at least one sensor (120, 220, 320, 420, 520). The at least one sensor (120, 220, 320, 420, 520) is configured to sense the tension member forces of the tension members of the bundle of tension members (103, 203, 303) attached to the tension member termination (401) and generate a signal relating to one or more tension members of the tension member bundle readable and/or measurable by the control unit (702) and proportional to the sensed load or force.