Bi-fold Door Safety Line Centrifugal Arrest Mechanism

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Solution Overview

Problem

Existing bi-fold door falling prevention devices are ineffective in cases of electrical power loss or complete mechanical failure of the lifting mechanism, leading to potential injuries and property damage.

Innovation Solution

A safety line assembly with an extendable and retractable tether system, powered by centrifugal force, is attached between the bi-fold door and the building wall, preventing uncontrolled falling by inhibiting extension above a threshold velocity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a lifting/lowering mechanism is used to control bi-fold door movement, then the door can be opened and closed efficiently, but the system becomes vulnerable to electrical power loss and mechanical failure leading to uncontrolled falling

Engineering Contradiction:

Improvedoor operation efficiencyVSAvoidsystem reliability during power loss or mechanical failure

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The safety system is segmented as an independent fall prevention mechanism separate from the lifting/lowering mechanism. The safety line assembly with reel and pawl-ratchet system operates independently to arrest door falls during power loss or mechanical failure, while the main lifting mechanism handles normal operation efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The safety line assembly is pre-positioned and pre-tensioned between the door and ceiling structure before any failure occurs. The reel mechanism with pawl-ratchet system is pre-configured to automatically engage and arrest falls, providing beforehand protection against uncontrolled door movement during power loss or mechanical failure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If an independent safety line assembly is added to prevent door falling, then reliability during power loss is improved, but device complexity increases

Engineering Contradiction:

Improvefall prevention reliabilityVSAvoidnumber of additional components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The safety line assembly operates autonomously without requiring external power or control systems. The reel mechanism automatically winds the safety line during door opening, and the pawl-ratchet system automatically engages to arrest falls, providing self-service fall prevention that improves reliability without requiring complex powered systems.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The safety line assembly uses simple, inexpensive mechanical components including a reel, pawl, and ratchet mechanism rather than complex electronic or powered systems. These simple mechanical parts provide reliable fall prevention while minimizing device complexity and cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 arrests the fall of bi-fold doors by ensuring they do not move beyond a safe velocity, even in the absence of electrical power or mechanical failure, thereby preventing injuries and damage.

Implementation Method 1

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS12031375B2Emergency bi-fold door closing prevention system

Publication Date: 2024.07.09 BRUSS AARON

AI summary

An emergency bi-fold door closing prevention system includes a building having an access opening with an upper edge. A bi-fold door is hingedly mounted to the building wall and includes a plurality of panels each being laterally elongated. The plurality of panels includes a bottom panel having a bottom edge that is positionable adjacent to a floor surface to define a closed position. A safety line assembly is attached to and extends between the building wall adjacent to the upper edge and the bi-fold door adjacent to the bottom edge. The safety line has an extendable length. The length of the safety line assembly extends when the bi-fold door moves toward the closed position below a threshold velocity. The length of the safety line assembly is inhibited from extending when the bi-fold door moves toward the closed position above the threshold velocity.