Elevator Position Tape Tensioning and Segmentation

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Solution Overview

Problem

Existing elevator position reference systems face accuracy and repeatability issues due to thermal elongation of measurement tapes, which affects position measurement accuracy.

Innovation Solution

The system employs tensioning of measurement tapes from both ends to evenly distribute thermal elongation and uses intermediate fixing devices to isolate tape portions, preventing vertical movement and mitigating elongation effects, thereby enhancing measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the position measurement tape is fixed at both ends to the hoistway wall, then the tape is stable and maintains its position, but thermal elongation causes measurement accuracy to deteriorate

Engineering Contradiction:
Improvetape position stabilityVSAvoidposition measurement accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent divides the position measurement tape into multiple segments by introducing intermediate support points (guiding clips) along the tape length. Each segment between support points can independently accommodate thermal expansion, preventing cumulative elongation errors across the entire tape length while maintaining overall tape stability through the support structure.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the tape is allowed to move freely vertically through clips, then thermal elongation can occur without constraint, but position measurement accuracy deteriorates due to unpredictable tape movement

Engineering Contradiction:
Improvetape thermal adaptationVSAvoidposition measurement repeatability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces guiding clips as intermediary elements that mediate between the tape and the hoistway structure. These clips provide controlled support points that allow the tape to adapt to thermal changes while maintaining predictable positioning, serving as intermediaries that enable thermal adaptation without compromising measurement repeatability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach allows for accurate prediction and compensation of thermal elongation, maintaining measurement accuracy and reducing errors caused by tape elongation, ensuring precise position determination within the elevator hoistway.

Implementation Method 1

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

Methodology Applied
Scientific EffectThermal elongation: Thermal Expansion

Data Source

PatentEP3978406B1Elevator position reference systems
Publication Date: 2024.02.14 OTIS ELEVATOR CO
  • EP3978406B1 patent drawingFigure 1
  • EP3978406B1 patent drawingFigure 2
  • EP3978406B1 patent drawingFigure 3

AI summary

An elevator position reference system (1) comprises a hoistway (4) extending in a vertical direction and a position measurement tape (8) arranged in the hoistway (4) to extend in the vertical direction. An upper tensioning device (10) is connected to an upper end (20) of the position measurement tape (8) so as to apply a tensioning force (30) to the position measurement tape (8) in the upwards vertical direction. A lower tensioning device (12) is connected to a lower end (22) of the position measurement tape (8) so as to apply a tensioning force (32) to the position measurement tape (8) in the downwards vertical direction.