Elevator Suspension Member Elongation Detection Using Time Differences
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Solution Overview
Problem
Elongation of suspension members in elevator systems is challenging to measure repeatedly and accurately due to its small scale, which affects the life and retained breaking strength of suspension members.
Innovation Solution
A system and method utilizing interactive elements and a control system to determine elongation by measuring time differences between the presence of the elevator car and counterweight, employing sensors such as Hall Effect sensors and RFID systems, without requiring an absolute position referencing system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional measurement methods are used to measure suspension member elongation, then measurement can be performed, but measurement precision is insufficient due to the very small scale of elongation
Solution Approach 1:
The patent replaces direct mechanical measurement of suspension member elongation with an optical detection system. Interactive elements (optical sensors) mounted on the suspension member detect position changes by reflecting light beams, converting mechanical elongation into optical signal measurements that can be detected with high precision.
Solution Approach 2:
The patent introduces interactive elements as intermediary components between the suspension member and the measurement system. These interactive elements consist of light-reflecting components that convert the small-scale mechanical elongation of the suspension member into larger, more measurable optical path changes, enabling precise indirect measurement.
2Measurement precision
If direct measurement of suspension member elongation is attempted, then elongation data can be obtained, but the system complexity increases due to requiring absolute position referencing systems
Solution Approach 1:
The patent divides the measurement system into separate functional segments: interactive elements mounted on the suspension member, fixed optical sensors mounted on the hoistway, and a control system. This segmentation allows each component to perform a specific function independently, simplifying the overall system architecture and eliminating the need for complex absolute position referencing systems.
Solution Approach 2:
The interactive elements on the suspension member and counterweight serve themselves by automatically reflecting light beams from fixed sensors. The system uses the relative motion between the moving components (suspension member, car, counterweight) and fixed sensors to self-generate measurement signals, eliminating the need for external complex positioning infrastructure.
3Measurement precision
If multiple sensors and positioning systems are deployed to measure elongation accurately, then measurement precision improves, but the cost and hardware requirements increase
Solution Approach 1:
The fixed optical sensors mounted on the hoistway serve multiple functions: they detect the position of the suspension member, the elevator car, and the counterweight using the same hardware component. This multi-functionality reduces the total number of sensors needed compared to traditional systems that would require separate positioning systems for each component.
Solution Approach 2:
The system discards expensive absolute position referencing infrastructure and recovers measurement capability through simple relative position detection. By measuring only the change in position over time rather than absolute position, the system achieves elongation measurement without requiring costly absolute positioning systems.
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
Provides a cost-effective and accurate method to monitor suspension member elongation continuously, reporting elongation with each trial and minimizing added hardware, ensuring timely detection of elongation thresholds.
Implementation Method 1
the first interactive element and the car interactive element comprise a first sensor system, and the second interactive element and the counterweight interactive element comprise a second sensor system... the first sensor system and the second sensor system comprise at least one of an optical sensor system, a Hall Effect sensor system
Implementation Method 2
the first sensor system and the second sensor system comprise at least one of an optical sensor system
Implementation Method 3
the first sensor system and the second sensor system comprise at least one of an optical sensor system, a Hall Effect sensor system, a RFID sensor system, an ultrasonic sensor system
Data Source
AI summary
A system and method for determining elongation of suspension members in an elevator system that includes an elevator car that is supported for movement within a hoistway by at least one suspension member and a counterweight that is coupled to the elevator car with the at least one suspension member. A first time is determined when the first interactive element detects a presence of the elevator car. A second time is determined when the second interactive element detects a presence of the counterweight. A speed and a direction of the elevator car are also determined. Elongation of the at least one suspension member is then determined by comparing a time difference between the first time and the second time to an elongation threshold.