Elevator Rope Position Sensing Gap Design
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Solution Overview
Problem
Existing elevator systems lack a simple and efficient method to monitor and react to the position of belt-shaped ropes passing around rope wheels, particularly in cambered configurations, leading to potential rope misalignment and safety issues.
Innovation Solution
A sensing arrangement with elongated sensing members positioned close to the rope wheels, featuring a gap that allows detection of rope displacement without causing damage, triggering actions such as stopping the drive wheel rotation to address misalignment, and preventing rope wedging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensing member is positioned close to the rope wheel to detect rope displacement, then measurement precision is improved, but the risk of damaging the ropes by the sensing member increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the gap distance between the sensing member and the rope wheel surface. The gap height h is set within a specific range (t < h < 2.2t, where t is rope thickness), transforming a potential harmful contact into a safe non-contact sensing arrangement that maintains high measurement precision while preventing rope damage.
Solution Approach 2:
The gap between the sensing member and the rope wheel acts as an intermediary space that allows the sensing member to detect rope position changes through the back surface of the ropes without direct contact. This intermediary arrangement enables accurate monitoring while eliminating the harmful effect of mechanical contact that could damage the ropes.
2Measurement precision
If the gap height is reduced to detect rope crossing situations, then measurement precision is improved, but the likelihood of unnecessary contacts during normal operation increases
Solution Approach 1:
The patent resolves this contradiction by optimizing the gap height parameter within a precise range (t < h < 2.2t). This parameter setting ensures the sensing member is close enough to detect rope crossing situations (when stacked ropes reach height 2t) while maintaining sufficient distance to avoid contact during normal single-rope operation, thus achieving both detection precision and operational reliability.
3Reliability
If the sensing member is positioned to detect any rope displacement, then safety is improved, but false alarms during normal rope wandering are triggered
Solution Approach 1:
The patent applies parameter changes by setting the gap height h greater than rope thickness t, which allows normal rope wandering and seeking of position on cambered contact areas without triggering false alarms. The sensing member only detects actual hazardous conditions (rope crossing or significant displacement) while tolerating normal operational variations, thus maintaining both safety and ease of operation.
Data Source
Figure 1~2b
Figure 3~4
Figure 5~6
AI summary
An elevator comprising an elevator car (1); a plurality of belt-shaped ropes (3a,3b,3c) connected to the car (1), each having a width larger than thickness as measured in transverse direction of the rope; and at least one rope wheel (5, 6), around which the belt-shaped ropes (3a,3b,3c) pass; wherein the rope wheel (5, 6) comprises a plurality of circumferential rope contact areas (A, B, C) distributed in axial direction thereof, one of said ropes (3a,3b,3c) passing against each circumferential rope contact area (A, B, C), the elevator further comprising a sensing arrangement (20, 30) for sensing displacement of one or more of said ropes (3a,3b,3c), comprising a sensing member (23, 33) for sensing displacement of one or more of said ropes (3a,3b,3c) radially outwards from the rope wheel (5,6), extending in axial direction of the rope wheel (5, 6) along its surface at a radial distance therefrom, whereby a gap (g) is formed between the sensing member (23, 33) and each rope contact area (A, B, C), the height (h) of the gap (g) being more than thickness (t) of the belt-shaped ropes (3a,3b,3c) and less than 2.2 times the thickness of the belt-shaped ropes (3a,3b,3c); sensing member (23, 33) being displaceable by a rope (3a,3b,3c) colliding into contact with it, and the sensing arrangement (20, 30) is arranged to trigger one or more predefined action in response to displacement of the sensing member (23, 33).