Compact Composite Handrail Design for Escalator Power Reduction
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Solution Overview
Problem
Existing handrails for escalators and moving walkways are inefficient in terms of power consumption due to their large size and weight, which affects their mechanical properties and durability under cyclic loading conditions.
Innovation Solution
A compact handrail design featuring a carcass with a stretch inhibitor and a cover made from thermoplastic materials, along with a sliding layer, which reduces weight and power requirements by optimizing the dimensions and material properties to enhance mechanical properties such as lip stiffness and straightness maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional large-sized handrails are used, then mechanical strength and durability are improved, but power consumption increases by 30-40%
Solution Approach 1:
The handrail employs a composite structure consisting of a thermoplastic carcass, a stretch inhibitor layer, and a cover layer. This multi-material composite design optimizes the strength-to-weight ratio, reducing power consumption while maintaining mechanical strength and durability under cyclic loading conditions.
2Use of energy by moving object
If handrail size is reduced to decrease power consumption, then weight and power requirements are reduced, but mechanical properties such as lip stiffness and straightness may deteriorate
Solution Approach 1:
The stretch inhibitor is positioned specifically within the carcass structure at locations where tensile stresses develop during flexing. This localized reinforcement strategy maintains lip stiffness and straightness in compact handrails without requiring overall size increase, thereby keeping power consumption reduced.
3Ease of manufacture
If thermoplastic materials are used for carcass and cover, then manufacturing ease and weight are improved, but mechanical strength under cyclic loading may be reduced
Solution Approach 1:
The combination of thermoplastic materials with a stretch inhibitor creates a composite structure that leverages the manufacturing advantages of thermoplastics while compensating for their lower cyclic loading strength through the reinforcing stretch inhibitor layer.
4Strength
If cable array stretch inhibitor is used, then resistance to cable buckling is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The stretch inhibitor cables utilize a specific strand configuration with large outer strands and small inner strands. This parameter optimization enables effective penetration and adhesion within the thermoplastic carcass during extrusion, reducing fretting and corrosion while maintaining manufacturing feasibility through a single-pass extrusion process.
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 compact handrail design reduces power consumption by 30-40% and improves mechanical properties like lip stiffness and straightness, making it more efficient and durable for use in transportation systems.
Implementation Method 1
A temperature sufficient to melt the thermoplastic material
Implementation Method 2
The extruded handrail may then be cooled to solidify the material
Data Source
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AI summary
A handrail includes a carcass, a stretch inhibitor arranged within the carcass, a cover bonded to the carcass, and a sliding layer secured to the carcass. At a central width axis of the handrail, a face height between an upper exterior surface of the cover and a bottom surface of the sliding layer may be less than about 8.0 mm. The carcass may be formed of a first thermoplastic material, the cover may be formed of a second thermoplastic material, and the first thermoplastic material may be harder than the second thermoplastic material. The first thermoplastic material may have a modulus at 100% elongation of between 10 and 16 MPa, and may have a hardness of between 93 and 96 Shore A.