Handrail Connection Stiffness Gradient via Temperature Control

Solution Overview

Problem

The existing moving handrails for passenger conveyors experience drastic changes in bending stiffness at the connection section, leading to local deformation and stress concentration, which shortens their lifespan due to uneven curing and reinforcement methods.

Innovation Solution

A moving handrail with a thermoplastic elastomer core and a tensile body, where the connection die's temperature is gradually reduced from the center to the outer side during heating, ensuring a more uniform curing and reduced bending stiffness difference between the connection and unheated sections, preventing drastic stiffness changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the connection die heats both end portions uniformly to connect them, then the connection strength is improved, but the bending stiffness changes drastically at the boundary between connection and unheated parts

Engineering Contradiction:

Improveconnection strengthVSAvoidbending stiffness uniformity

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating a temperature gradient within the connection die, where the heating temperature varies from the longitudinal intermediate portion to the longitudinal outer side. This results in different curing degrees at different locations within the connection section, with the intermediate portion having higher curing degree and the outer portions having lower curing degree, thereby achieving gradual bending stiffness transition.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the temperature parameter spatially within the connection die. By setting the heating temperature to be lower from the longitudinal intermediate portion toward the longitudinal outer side, the curing degree of the thermoplastic elastomer varies accordingly, creating a gradient in bending stiffness that prevents abrupt transitions at the boundaries.

Inventive Principle:

Principle #35Parameter changes

2Strength

If reinforcement fabric or overlapping tensile body is added to the connection section, then the connection strength is improved, but the bending stiffness difference between connection and unheated parts is enlarged

Engineering Contradiction:

Improveconnection strengthVSAvoidbending stiffness uniformity

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating a temperature gradient within the connection die, where the heating temperature varies from the longitudinal intermediate portion to the longitudinal outer side. This results in different curing degrees at different locations within the connection section, with the intermediate portion having higher curing degree and the outer portions having lower curing degree, thereby achieving gradual bending stiffness transition.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the temperature parameter spatially within the connection die. By setting the heating temperature to be lower from the longitudinal intermediate portion toward the longitudinal outer side, the curing degree of the thermoplastic elastomer varies accordingly, creating a gradient in bending stiffness that prevents abrupt transitions at the boundaries.

Inventive Principle:

Principle #35Parameter changes

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 extends the lifespan of the handrail by minimizing local deformation and stress concentration, ensuring a smoother stiffness transition and reducing the risk of kinking or stress concentration at the connection boundaries.

Implementation Method 1

both the end portions of the handrail main body are heated with the connection die

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

the thermoplastic elastomer of the core body, which has melted by being heated with the connection die

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

the thermoplastic elastomer of the core body, which has melted by being heated with the connection die, penetrates through the canvas to be cured

Methodology Applied

Scientific EffectCuring: Phase Change

Data Source

PatentUS9481552B2Moving handrail for passenger conveyor, and device for manufacturing moving handrail for passenger conveyor

Publication Date: 2016.11.01 MITSUBISHI ELECTRIC CORP

AI summary

An endless moving handrail for a passenger conveyor is formed by heating and connecting together both end portions of a handrail developed body with a connection die. The handrail developed body includes a core body that is made of a thermoplastic elastomer and has a substantially C-shaped cross section, a tensile body arranged inside the core body along a longitudinal direction of the core body, and a canvas arranged on an inner surface of the core body. In the moving handrail for a passenger conveyor, both the end portions of the handrail developed body heated with the connection die are formed as a handrail connection section. A bending stiffness of the handrail connection section is reduced from a longitudinal intermediate portion toward a longitudinal outer side of the handrail connection section.