Fire Door Guide Mechanism for Thermal Expansion Stress

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Solution Overview

Problem

Fire doors experience stress concentration and potential damage due to thermal expansion, leading to disengagement of spacers from guides, which reduces their strength and effectiveness in preventing flames, smoke, and hot air from passing through.

Innovation Solution

A fire door design with a guide member that includes upper and lower guided portions and a restricting portion, where the upper guided portion is supported from below and moves upwardly away from the upper guide portion during thermal expansion, preventing stress concentration and maintaining movement restriction along the fore and aft direction through contact portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the door body is guided using spacers engaging with slide packs and linear guides, then smooth movement along the lateral direction is achieved, but stress concentration occurs during thermal expansion leading to disengagement and loss of fore and aft movement restriction

Engineering Contradiction:

Improvesmooth movementVSAvoidengagement reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The guide member is divided into an upper guide portion and a lower guide portion, with the upper guide portion supported from below by the lower guide portion. This segmentation allows independent movement and stress distribution, preventing stress concentration at a single engagement point while maintaining smooth lateral movement guidance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The upper guide portion is designed to be movable relative to the lower guide portion along the vertical direction during thermal expansion. This dynamic configuration allows the guide structure to adapt to thermal changes, maintaining engagement reliability while accommodating door body expansion without disengagement.

Inventive Principle:

Principle #15Dynamics

2Strength

If the door body is constrained to prevent fore and aft movement, then strength is maintained during operation, but stress concentration occurs at engagement areas during thermal expansion

Engineering Contradiction:

Improvedoor body strengthVSAvoidstress concentration

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The guide member is divided into upper and lower portions that can move independently. This segmentation distributes the stress of thermal expansion across multiple points and allows progressive deformation, preventing stress concentration at single engagement areas while maintaining overall structural strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The configuration allows the upper guide portion to move upward relative to the lower guide portion during thermal expansion, creating a cushioning effect that absorbs expansion stress before it can concentrate at the engagement points, thereby preventing damage while maintaining strength.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If the upper spacers and lower spacers are fixed to guide the door, then lateral movement guidance is achieved, but the vertical distance between them increases during thermal expansion causing disengagement

Engineering Contradiction:

Improveguidance accuracyVSAvoidvertical distance

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The upper guide portion is designed to move vertically relative to the lower guide portion during thermal expansion. This dynamic adjustment maintains the functional relationship between the guide portions while accommodating changes in vertical distance, preventing disengagement while maintaining guidance accuracy.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The solution allows movement in the vertical dimension to accommodate thermal expansion, while maintaining constraint in the lateral dimension for accurate guidance. By permitting controlled movement in one dimension (vertical) while maintaining precision in another (lateral), the system resolves the contradiction between fixed spacing and thermal expansion.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Prevents damage to the door body by distributing stress and maintaining strength by restricting movement along the fore and aft direction, ensuring effective closure during fires and firefighting efforts.

Implementation Method 1

the door main body has expanded from an initial form due to heat from a fire

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9670715B2Fire door

Publication Date: 2017.06.06 DAIFUKU CO LTD

AI summary

A door body includes a door main body, an upper guided portion provided to an upper portion of the door main body, and a lower guided portion provided to a lower portion of the door main body. A guide member includes an upper guide portion, a lower guide portion, and a restricting portion. The upper guide portion supports the upper guided portion from below while restricting movement of the upper guided portion along the fore and aft direction. The lower guide portion supports the lower guided portion from below while restricting movement of the lower guided portion along the fore and aft direction. The upper guided portion is moved upwardly away from the upper guide portion in the expanded support state. The restricting portion restricts movement of the door main body in the first direction in the expanded support state, and restricts movement of the door main body in the second direction in the expanded support state.