Elevator Door Anti-Falling Device with Elastic Roller

Solution Overview

Problem

Conventional anti-falling devices for elevator doors often cause abnormal noise due to collisions between metal rollers and the door rail, especially when the door tilts during opening or closing operations.

Innovation Solution

An anti-falling device for elevator doors featuring a first metal roller positioned away from the door rail and a second elastic roller that maintains contact with the rail, with the second roller placed between the first roller and the door's center, absorbing forces to prevent collisions and reduce noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the pair of rollers are arranged downwardly away from the lower end surface of the door rail to eliminate contact resistance, then the door can slide smoothly during opening and closing operations, but a clearance is formed in the vertical direction between the lower end surface of the door rail and each of the pair of rollers, causing abnormal noise when the door tilts and either roller collides with the door rail

Engineering Contradiction:

Improvedoor sliding smoothnessVSAvoidabnormal noise

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The door hanger is divided into two functional parts: a first roller that maintains clearance for smooth sliding, and a second roller that provides elastic contact for noise reduction. This segmentation allows each component to fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second elastic roller acts as an intermediary between the door hanger and the door rail, absorbing impact forces through elastic deformation and preventing direct metal-to-metal contact that would generate abnormal noise during door tilting operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the pair of metal rollers are held in contact with the lower end surface of the door rail to prevent door tilting, then the door stability is improved, but contact resistance occurs between the metal rollers and the door rail, increasing friction during opening and closing operations

Engineering Contradiction:

Improvedoor stabilityVSAvoidcontact resistance

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

Different rollers are assigned different material properties and contact characteristics: the first roller is made of metal with clearance for low-friction sliding, while the second roller is made of elastic material with contact for stability. This local differentiation optimizes both stability and friction reduction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the material parameter of the second roller from metal to elastic material, transforming it from a rigid contact element that generates friction to a compliant element that provides stability through elastic deformation, thereby reducing contact resistance while maintaining door stability.

Inventive Principle:

Principle #35Parameter changes

3Force

If the first roller is made of metal and arranged away from the door rail, then the door can open and close with reduced friction, but the door may tilt and cause the first roller to collide with the door rail, generating abnormal noise

Engineering Contradiction:

Improvefriction reductionVSAvoidabnormal noise

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The door hanger is divided into two functional parts: a first roller that maintains clearance for smooth sliding, and a second roller that provides elastic contact for noise reduction. This segmentation allows each component to fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second elastic roller acts as an intermediary between the door hanger and the door rail, absorbing impact forces through elastic deformation and preventing direct metal-to-metal contact that would generate abnormal noise during door tilting operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively reduces abnormal noise by absorbing forces and preventing direct contact between the first roller and the door rail, while maintaining the door's stability and reducing torque requirements for opening and closing operations.

Implementation Method 1

a second roller provided on the door hanger, arranged to face the lower end surface of the door rail, and configured to be in elastic contact with the door rail

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11427442B2Anti-falling device for elevator door

Publication Date: 2022.08.30 FUJITEC CO LTD

AI summary

An anti-falling device for a door of an elevator of the present invention includes: a door hanger; and a first roller and a second roller both provided on the door hanger and arranged to face a lower end surface of the door rail. The first roller is made of a metal is and arranged at a position downwardly away from the lower end surface of the door rail. The second roller is configured to be in elastic contact with the door rail, and is arranged to be held in contact with the lower end surface or arranged at a position closer to the lower end surface than the first roller.