Elevator Position Reference Using Opposing Tensioned Measurement Tapes
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Solution Overview
Problem
Elevator position reference systems face inaccuracies due to thermal elongation and building settlement, which affect the accuracy of elevator car positioning and stopping precision, especially in high-rise buildings.
Innovation Solution
The implementation of two position measurement tapes, tensioned in opposite directions, allows for the cancellation of thermal elongation effects and provides redundant data for improved accuracy and building settlement monitoring, enabling precise elevator positioning and long-term building movement tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single position measurement tape is used in the hoistway, then the system structure is simple, but thermal elongation causes position measurement inaccuracies
Solution Approach 1:
The single position measurement tape is segmented into two separate tapes (first and second position measurement tapes) with opposite tensioning directions. This segmentation allows each tape to be tensioned independently, compensating for thermal elongation effects and improving measurement accuracy without creating a single complex integrated system.
Solution Approach 2:
The first and second position measurement tapes are tensioned in opposite vertical directions (upwards and downwards respectively), creating a counterbalancing system. The opposite tensioning forces act as counterweights that compensate for thermal elongation, as when one tape elongates due to heat, the other tape's opposite tension maintains the overall measurement accuracy.
2Reliability
If position measurement tapes are fixed rigidly at both ends, then the tape position is stable, but building settlement and thermal expansion cause measurement errors
Solution Approach 1:
The system transitions from rigid fixed-end constraints to a dynamic tensioning system. The tensioning devices allow the tapes to adapt to building settlement and thermal expansion dynamically, maintaining measurement reliability while compensating for environmental changes through controlled tension adjustments.
Solution Approach 2:
The tensioning parameters of the position measurement tapes are changed from fixed rigid constraints to adjustable dynamic tensioning. The upper and lower tensioning devices modify the tension parameters in opposite directions, allowing the system to adapt to thermal expansion and building settlement while maintaining measurement precision.
3Measurement precision
If tensioning devices are added to compensate for thermal elongation, then position measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The tensioning devices serve multiple functions: they provide thermal compensation, maintain tape tension, enable building settlement monitoring, and support redundant measurement capabilities. This multi-functionality reduces the need for separate compensation mechanisms, thereby limiting the increase in device complexity while improving measurement accuracy.
Solution Approach 2:
The upper and lower tensioning devices are merged into a coordinated system that simultaneously performs thermal compensation and position reference functions. By combining these functions into an integrated tensioning system, the patent reduces overall device complexity compared to having separate independent compensation mechanisms.
4Measurement precision
If two position measurement tapes with opposite tensioning are used, then thermal elongation effects are cancelled, but the system complexity and cost increase
Solution Approach 1:
The patent converts the harmful effect of thermal elongation into a beneficial compensation mechanism. By tensioning two tapes in opposite directions, the thermal expansion of one tape is compensated by the contraction tendency of the other, transforming the harmful thermal effect into a self-correcting system that improves absolute position accuracy.
Solution Approach 2:
The system uses asymmetric tensioning directions (one upwards, one downwards) to create complementary compensation effects. This asymmetric arrangement allows each tape to counteract the thermal elongation of the other, achieving accurate cancellation of thermal effects while maintaining a relatively simple dual-tape configuration.
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 solution enhances the accuracy of elevator positioning and building settlement monitoring, ensuring precise and reliable operation even in high-rise environments by compensating for thermal expansion and settlement-induced errors.
Implementation Method 1
an upper tensioning device, connected to an upper end of the first position measurement tape so as to apply a tensioning force to the first position measurement tape in the upwards vertical direction
Implementation Method 2
a lower tensioning device, connected to a lower end of the second position measurement tape so as to apply a tensioning force to the second position measurement tape in the downwards vertical direction
Implementation Method 3
The accuracy and repeatability of position measurements in an elevator position reference system may depend on elongation phenomena affecting the tape due to temperature variations in the hoistway
Data Source
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AI summary
An elevator position reference system and a method of monitoring building settlement using such a system are disclosed. The elevator position reference system (3) includes a hoistway (4) extending in a vertical direction. The system also includes a first position measurement tape (8a) extending vertically along a portion of the hoistway (4) and an upper tensioning device (10), connected to an upper end (20a) of the first position measurement tape (8a) so as to apply a tensioning force (30) in the upwards vertical direction. A lower end (22a) of the first position measurement tape (8a) is fixed within the hoistway (4). The system also includes a second position measurement tape (8b) extend vertically along at least some of said portion of the hoistway (4) and a lower tensioning device (12), connected to a lower end (22b) of the second position measurement tape (8b) so as to apply a tensioning force (32) in the downwards vertical direction. An upper end (20b) of the second position measurement tape (8b) is fixed within the hoistway (4).