Escalator Handrail Composite Cover for Grip and Ozone Resistance
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Solution Overview
Problem
Existing handrails for escalators and moving walkways face challenges in maintaining performance under stressful environmental conditions, such as high temperatures and ozone pollution, while also ensuring efficient operation and user safety, with rubber handrails suffering from surface contamination and plastic handrails having reduced traction and increased bending stiffness.
Innovation Solution
A handrail design featuring a carcass with a thermoplastic elastomer cover layer, providing a C-shaped cross-section for flexibility and stability, combined with a sliding layer and tension element for reduced energy consumption and enhanced durability, allowing for efficient operation across various environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rubber handrails are used to provide flexibility and dynamic behavior, then good wear resistance and dynamic behavior are achieved, but surface contamination occurs under high temperature and ozone conditions
Solution Approach 1:
The handrail uses a composite structure combining an elastomeric base material with a protective top layer. The base material provides flexibility and dynamic behavior, while the top layer (made of fluoropolymer, polyethylene, or polypropylene) prevents surface contamination by creating a barrier against ozone and UV radiation, eliminating the need for protective ingredients that would otherwise migrate to the surface.
Solution Approach 2:
The invention changes the chemical composition parameters of the handrail by incorporating specific protective ingredients (antiozonants and UV stabilizers) at controlled concentrations (0.1-5 wt% and 0.01-1 wt% respectively) into the elastomeric material. This allows the material to maintain its dynamic properties while resisting environmental degradation without excessive surface migration.
2Manufacturing precision
If plastic handrails are used to provide a shiny surface and dimensional stability, then surface properties are improved, but bending stiffness increases leading to reduced traction performance
Solution Approach 1:
The invention changes the material parameters by using an elastomeric base material with specific Shore A hardness (50-80) and tensile strength (5-20 MPa) properties. This provides the necessary flexibility for good traction performance on escalators with small bending radii, while the reinforced carcass structure maintains dimensional stability.
Solution Approach 2:
The handrail employs a composite structure with an elastomeric outer layer providing flexibility and traction, combined with an internal carcass structure (made of steel wires, fabric, or rigid foam) that provides dimensional stability and structural support, achieving both requirements simultaneously.
3Reliability
If protective ingredients are increased in rubber handrails to prevent degradation, then durability is improved, but surface contamination increases
Solution Approach 1:
The invention uses a layered composite structure where the elastomeric base material contains the necessary protective ingredients for durability, while the inert top layer (fluoropolymer, polyethylene, or polypropylene) acts as a barrier that prevents these ingredients from migrating to the surface, thus maintaining both durability and surface cleanliness.
Solution Approach 2:
The top layer acts as an intermediary barrier between the elastomeric base material and the external environment. It protects the base material's protective ingredients from coming into contact with the surface, preventing contamination while still allowing the base material to provide its protective functions.
4Productivity
If bending radius is reduced to save installation costs, then installation efficiency is improved, but handrail durability decreases due to increased stress
Solution Approach 1:
The invention changes the mechanical parameters of the handrail by optimizing the elastomeric material's tensile strength (5-20 MPa), elongation at break (100-400%), and Shore A hardness (50-80). These parameter adjustments allow the handrail to withstand the increased stress from smaller bending radii while maintaining durability.
Solution Approach 2:
The reinforced carcass structure (steel wires, fabric reinforcement, or rigid foam core) provides additional structural support that compensates for the increased stress from reduced bending radii, allowing the handrail to maintain durability even when installed with tighter curves to save space and installation costs.
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
The handrail achieves improved dynamic behavior, surface properties, and resistance to environmental factors, ensuring secure grip and efficient operation with reduced energy consumption and extended service life.
Implementation Method 1
The cover layer preferably comprises a thermoplastic elastomer
Data Source
AI summary
A handrail mountable on a guide element for moving walkways, escalators or the like, and having a largely constant cross-section along a profile direction the handrail including a carcass configured to be arranged on the guide element, and a cover layer arranged on the carcass, wherein the cover layer comprises a thermoplastic elastomer.