Composite Metal Plastic Door Leaf Frame Design

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Solution Overview

Problem

Existing metal front doors face challenges in achieving optimal thermal insulation and industrial manufacturability while maintaining burglary protection and design appeal, particularly due to visible joints between the door leaf frame and panel.

Innovation Solution

A door leaf frame constructed from a metal half-shell and a plastic half-shell, connected via tongue and groove connections, with foam insulation between the panels and frame, allowing for improved thermal insulation and rigidity without the need for additional connecting webs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal door leaf frame is used for burglary protection and durability, then strength and reliability are improved, but thermal insulation deteriorates due to high thermal conductivity of metal

Engineering Contradiction:
Improveburglary protectionVSAvoidthermal insulation
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent applies composite materials by combining metal and plastic half-shells in the door leaf frame. The metal half-shell provides burglary protection and structural strength, while the plastic half-shell provides thermal insulation. This composite construction resolves the contradiction by integrating both functional requirements into a single frame structure.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If connecting webs made of poorly thermally conductive material are added to insulate the metal frame, then thermal insulation is improved, but device complexity increases

Engineering Contradiction:
Improvethermal insulationVSAvoidframe structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges the frame structure and insulation function by making the plastic half-shell itself the insulating element. Instead of adding separate connecting webs, the plastic material forming the half-shell provides both structural support and thermal insulation, thereby reducing device complexity while maintaining insulation performance.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the door panel is inserted into the door leaf frame, then ease of manufacture is improved, but visible gaps appear between frame and panel reducing design quality

Engineering Contradiction:
Improvepanel installationVSAvoidvisible gap
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The patent addresses the visible gap issue by extending the half-shells in the width direction beyond the panel edges. This dimensional extension allows the frame to overlap the panel, creating a flush appearance without compromising the ease of panel installation. The half-shells act as both structural elements and aesthetic covers.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Shape

If both door leaf frame and panel are painted for full-coverage design, then design quality is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvefull-coverage designVSAvoidmanufacturing process
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by designing the plastic half-shell to serve both as a structural component and as the aesthetic outer surface. The plastic half-shell is supplied in the final color, eliminating the need for separate painting operations on both frame and panel. This reduces manufacturing complexity while achieving full-coverage design appearance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This configuration enhances thermal insulation, burglary protection, and manufacturability by creating a strong, rigid door leaf frame with improved sealing and design aesthetics, while simplifying the production process.

Implementation Method 1

The door leaf cavity is completely surrounded by insulation (38). The insulation is formed by foaming the door leaf cavity formed between the door leaf frame and the panels placed on it.

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

The two half-shells are connected to each other by several tongue-and-groove connections (106), in which a tongue formation (108) on one half-shell engages a groove formation (110) on the other half-shell in a form-fitting manner.

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP2581542B2House door leaf and method for manufacturing same
Publication Date: 2023.07.26 HORMANN KG ECKELHAUSEN
  • EP2581542B2 patent drawingFigure 1~2
  • EP2581542B2 patent drawingFigure 3
  • EP2581542B2 patent drawingFigure 4

AI summary

The invention relates to a front door leaf (14) with a door leaf frame (40) and panels (28, 32) forming the door leaf broad sides (26, 30) and with insulation (38) between the panels (28, 32), wherein the door leaf frame (40) is formed from a metal half-shell (42) and a plastic half-shell (44).