Door Leaf Connecting Profile for Thermal Expansion Management

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Solution Overview

Problem

Conventional door leaves experience visible deformations and distortion due to temperature fluctuations, particularly when exposed to sunlight, as the thermally insensitive insulating materials between the panels do not participate in thermally induced movements, leading to mechanical stresses and bulges in the paneling.

Innovation Solution

A door leaf design featuring a panel-shaped structure with a connecting profile that extends beyond the insulating layer, incorporating mechanical connecting elements like pins, bolts, and screws, allowing for a flexible connection between the weather-side paneling and the door leaf frame, enabling relative movement to accommodate thermal expansions, and utilizing elastic stops and sealing elements to manage temperature-induced stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid insulating material is used between the panels, then thermal and acoustic insulation is improved, but the insulating layer causes warping and bulges in the panels due to temperature fluctuations

Engineering Contradiction:
Improveinsulation performanceVSAvoidpanel deformation
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The insulating layer is segmented into multiple independent foam cores instead of being a single solid piece. This segmentation allows each foam core to independently accommodate thermal expansion and contraction of the panels without causing deformation, while still providing effective thermal and acoustic insulation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insulating material changes from a solid, rigid structure to a foamed, flexible structure with cellular geometry. This parameter change in material structure allows the insulation to maintain its thermal and acoustic properties while gaining the ability to flex and accommodate panel movements caused by temperature variations.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the panels are rigidly fixed to the door leaf frame, then structural stability is improved, but thermal expansion causes visible deformations and bulges

Engineering Contradiction:
Improvestructural stabilityVSAvoidvisible deformation
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The connection between the panels and door leaf frame transitions from a rigid, static connection to a dynamic, flexible connection through the foam core. The foam allows the panels to move relative to the frame in response to thermal expansion while maintaining overall structural stability, preventing visible deformations.

Inventive Principle:
Principle #15Dynamics

3Length of moving object

If the insulating layer is made thin, then the door leaf thickness is reduced, but insulation effectiveness and stress absorption are compromised

Engineering Contradiction:
Improvedoor leaf thicknessVSAvoidinsulation effectiveness
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The foam core acts as a flexible insulating film that provides effective thermal and acoustic insulation in a thin profile. The cellular structure of the foam allows it to maintain insulation performance while being thin enough to accommodate panel movements without requiring excessive thickness.

Inventive Principle:
Principle #30Flexible shells and thin films

4Strength

If mechanical connecting elements are used to secure the panels, then structural strength is improved, but the connection creates stress points that lead to deformations under thermal load

Engineering Contradiction:
Improvestructural strengthVSAvoidpanel distortion
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The foam core serves as an intermediary between the panels and the mechanical connecting elements. It distributes the mechanical loads and thermal stresses uniformly across the panel surfaces, preventing stress concentration at connection points that would otherwise cause localized deformations and bulges.

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 mechanical stresses and prevents visible deformations by allowing the weather-side paneling to float relative to the door leaf frame, absorbing thermal expansions and ensuring a secure, distortion-free structure.

Implementation Method 1

the insulating layer (9) made of insulating material arranged between these two cover plates (7, 8)... serves for thermal and/or acoustic insulation

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

Under sunlight, the weather-facing paneling (paneling) can heat up and expand... thermally induced movements or expansions of the surrounding components

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3854982A1Door leaf and door with a fixed frame and a door leaf
Publication Date: 2021.07.28 HYDRO BUILDING SYSTEMS LUEDENSCHEID GMBH
  • EP3854982A1 patent drawingFigure 1
  • EP3854982A1 patent drawingFigure 2~3
  • EP3854982A1 patent drawingFigure 4~5

AI summary

The invention relates to a door leaf (4) with a surrounding door leaf frame (5) and a panel-shaped door infill (6). The door infill (6) has a first panel (7) and a second panel (8) spaced apart from it, wherein an insulating layer (9) is incorporated at least partially between the first and second panels (7, 8). According to the invention, the first panel (7) has an edge region (10) that projects beyond the insulating layer (9) and the second panel (8), and the door leaf (4) further comprises a connecting profile (12; 28; 36) which is connected to the first panel (7) at the surface (11) of the edge region (10) facing the insulating layer (9) and extends in the longitudinal direction of the edge region (10). The connecting profile (12; 28; 36) is designed to accommodate primary expansions/contractions in a vertical direction and secondary expansions/contractions in a horizontal plane.