Fire Door Leaf Hooking Device for Thermal Deformation

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Solution Overview

Problem

Fire protection doors face challenges in withstanding deformation forces during fires, leading to potential gaps between door leaves and frames that can allow smoke and fire gases to escape, especially in multi-leaf configurations where hinges and catches provide limited support.

Innovation Solution

A fire-rated door leaf design featuring a hooking device with a metal reinforcement plate and a guide device that engages behind another door element, allowing controlled movement and tension relief to prevent excessive stress and maintain sealing, even under deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fire protection doors use only hinges and catches to hold door leaves, then the structure is simple, but the door leaves cannot withstand deformation forces during fires and gaps form allowing smoke and fire gases to escape

Engineering Contradiction:
Improvefire protection performanceVSAvoiddoor leaf support structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The support function is segmented between hinges, catches, and the newly introduced interlocking device with detection element. The detection element specifically handles the function of preventing gap formation during thermal deformation, while hinges and catches handle positioning and locking. This segmentation allows each component to be optimized for its specific function, improving overall reliability without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The detection element acts as an intermediary component between the door leaf and the frame. It mediates the thermal deformation forces by providing an additional support point that prevents the door leaf from pulling away from the frame during fire conditions, thereby preventing gap formation without requiring complete redesign of the hinge or catch mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the door leaf structure is simplified to reduce manufacturing complexity, then manufacturing is easier, but the door cannot absorb bending forces during fire and gaps form

Engineering Contradiction:
Improvedoor leaf constructionVSAvoidresistance to bending forces
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The detection element is designed to be movable rather than fixed, allowing it to dynamically adapt to thermal deformation. The element can move between a retracted position (normal conditions) and an extended position (fire conditions), providing strength when needed while maintaining ease of manufacture through a relatively simple movable structure rather than a complex rigid reinforcement.

Inventive Principle:
Principle #15Dynamics

3Reliability

If detection element is designed to hook onto further door element during fire, then tensile force prevents gap formation, but the detection element must be complex enough to engage and disengage properly

Engineering Contradiction:
Improvesealing performance during fireVSAvoidinterlocking device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of designing a complex active mechanism that protrudes and actively engages with the further door element, the invention uses a passive approach where the detection element is pulled out by thermal deformation and passively hooks onto the further door element. This inversion of the engagement mechanism reduces complexity while maintaining reliable sealing performance.

Inventive Principle:
Principle #13The other way round (Inversion)

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 counteracts bending forces during fires, ensuring the door leaves remain sealed and preventing the escape of smoke and fire gases, while also simplifying manufacturing and assembly processes.

Implementation Method 1

due to the hooking a tensile force acts in such a way that the detection element is moved from a normal position into an extended position

Methodology Applied
Scientific EffectTensile force: Tension

Implementation Method 2

The so-called 'bi-metal effect' occurs in fire tests of this kind in the case of fire protection doors whose door leaves are constructed from sheet metal jackets with fillings in them. The shell sheet facing the fire expands more than the sheet facing away from the fire due to the greater heat.

Methodology Applied
Scientific EffectBi-metal effect: Thermal Expansion

Data Source

PatentEP2878754B1Fire door leaf for a single or multi-leaf fire door
Publication Date: 2020.07.08 HORMANN KG FREISEN
  • EP2878754B1 patent drawingFigure 1
  • EP2878754B1 patent drawingFigure 2~4
  • EP2878754B1 patent drawingFigure 5~6

AI summary

The invention relates to a fire door leaf (100, 200, 300, 500) for a fire door (10). The fire door leaf (100, 200, 300, 500) has at least one outer sheet (101, 201, 301, 501) and a core (102). A locking device (140, 340, 540) arranged on the outer sheet (101, 201, 301, 501) is provided for engaging behind another door element of the fire door (10). The locking device (140, 340, 540) comprises a metal gripping element (141, 341, 541) for gripping the other door element. In case of fire, the detection element (141, 341, 541) can be moved from a normal position (144) to an extended position by applying a tensile force (F) when hooking it back.