Coated Elevator Rope Clamp for Static Charge Grounding
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Solution Overview
Problem
Coated elevator ropes experience static charge buildup due to non-conductive polymer coatings, leading to potential sparks and repelling of elevator ropes, which can result in derailing, especially when using polymer diverting pulleys, as opposed to traditional steel wire ropes that do not experience static electricity issues.
Innovation Solution
A clamp with piercing instruments on the wedge and internal tapered hollow that penetrate the coating to establish electrical contact with the conductive tensile members, ensuring the clamp holds the rope mechanically and electrically grounds static charge, using conductive materials and designs that prevent incorrect insertion and stress fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a non-conductive polymer coating is applied to protect steel filaments, then abrasion resistance is improved, but static charge buildup occurs leading to sparks and rope repelling
Solution Approach 1:
The clamp is divided into functionally distinct zones: a first friction surface with high surface roughness for mechanical gripping, and a second friction surface with low surface roughness for electrical contact. This segmentation allows each zone to optimize its specific function while working together as a unified clamp structure.
Solution Approach 2:
Different regions of the clamp are given different surface properties: the first friction surface has high roughness (Ra ≥ 0.4 μm) for mechanical friction, while the second friction surface has low roughness (Ra ≤ 0.05 μm) for electrical conduction. This local differentiation resolves the contradiction by providing both abrasion resistance through mechanical grip and static charge dissipation through electrical contact paths.
2Object-affected harmful factors
If traditional steel wire ropes are used, then static charge issues are avoided, but hoisting machine size and weight increase
Solution Approach 1:
The clamp acts as an intermediary device that enables coated elevator ropes to function without static charge problems. By providing a conductive path through its low-roughness friction surface, the clamp allows static charge to dissipate while maintaining the mechanical grip needed for rope termination, thus enabling the use of lighter coated ropes instead of traditional steel wire ropes.
3Force
If high surface roughness is applied to the friction surface, then mechanical gripping is improved, but electrical contact with conductive members is reduced
Solution Approach 1:
The clamp's friction surface is segmented into two distinct zones with different roughness characteristics. The first zone has high roughness for mechanical gripping, while the second zone has low roughness for reliable electrical contact. This segmentation resolves the contradiction by providing both functions in different locations rather than requiring a compromise in a single uniform surface.
Solution Approach 2:
Different local regions of the clamp are optimized for different functions: the first friction surface region has high surface roughness to maximize mechanical friction and gripping force, while the second friction surface region has low surface roughness to ensure reliable electrical contact with the conductive core members. This local quality differentiation allows both contradictory requirements to be satisfied simultaneously in their respective zones.
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
Effectively grounds static electricity, preventing sparks and repelling forces, ensuring secure rope termination and reducing the risk of derailing, while maintaining the benefits of coated ropes in reducing hoisting machine size and weight.
Implementation Method 1
The piercing instruments are effective to pierce through the coating and establish an electrical contact between the wedge and the tensile member
Implementation Method 2
The friction surface of the wedge receiving compartment that is closer to the loose end of the flat belt is provided with a surface roughness that is higher than that of the remaining surface of the wedge compartment
Data Source
AI summary
The invention relates to a clamp or termination for a coated elevator rope in an elevator. When coated elevator ropes are used electrostatic charge may build up in the ropes due to the insulating coating. These charges generate repelling or attracting forces between the parallel ropes, which hampers the correct miming of the ropes in the pulleys and in extreme cases may derail the coated elevator ropes. The wedge and socket clamps according the invention discriminate themselves from prior art wedge and socket clamps in that the piercing instruments are provided in the low tension zone of the clamp. These piercing instruments can take the form of pins, fins or other protrusions and establish an electrical connection between the wedge and the conductive tensile member. Such an elevator clamp allows to leak static electricy being build up or allows wear detection per elevator rope.