Thermoplastic Window Frames with Interlocking Corners and Thermal Breaks

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Solution Overview

Problem

Existing window and door frame systems face challenges with thermal insulation, dimensional stability, and water ingress due to differential thermal expansion between materials, and they struggle to efficiently anchor fittings and provide seamless coverage with different materials.

Innovation Solution

A thermoplastic profile with internal longitudinal walls for multiple screw anchoring, protruding webs for cover profile attachment, and co-extruded seals, along with a T-shaped profile for precise glass pane coverage, addresses these issues by ensuring dimensional stability and efficient water drainage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If profiles are covered with individual mitred parts, then coverage is achieved, but joints become visible and deformation occurs due to differential thermal expansion

Engineering Contradiction:
Improvecoverage attachmentVSAvoidjoint appearance and dimensional stability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent merges the cover profiles into a continuous frame structure with interlocking corner joints, eliminating visible mitred joints. The corner joints integrate multiple cover profile ends into a unified appearance, resolving the issue of visible joints while maintaining ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces compensation elements that allow for thermal expansion and contraction movements. These elements change their physical state or position in response to temperature variations, absorbing dimensional changes and preventing deformation and visible joint gaps caused by differential thermal expansion between PVC frames and aluminum cover profiles.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If aluminum profiles are attached externally to PVC frames, then weather protection is improved, but thermal bridges increase and thermal insulation deteriorates

Engineering Contradiction:
Improveweather protectionVSAvoidthermal insulation
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent introduces thermal break elements as intermediaries between the PVC frame and aluminum cover profiles. These elements mediate the thermal connection, allowing mechanical attachment while minimizing heat transfer. The thermal break elements create a discontinuity in the thermal path, preventing direct thermal bridges while maintaining the protective function of the aluminum profiles.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If fiber-reinforced plastic profiles are used, then dimensional stability improves, but welding capability is lost and water ingress occurs at corners

Engineering Contradiction:
Improvedimensional stabilityVSAvoidwater tightness
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent employs composite construction for corner joints, combining fiber-reinforced plastic profile sections with compatible joining mechanisms. The corner joints are designed as integrated composite structures that maintain the dimensional stability of fiber-reinforced plastic while incorporating features for water tightness, such as integrated sealing channels and interlocking geometries that prevent water ingress without requiring welding.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If profile cross-section is reduced by applied covering profile, then coverage is achieved, but fitting anchoring efficiency decreases

Engineering Contradiction:
Improvecover attachmentVSAvoidfitting anchoring
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent resolves the conflict between coverage and anchoring by transitioning to a different dimensional approach. Instead of reducing the profile cross-section, the design maintains full profile depth and utilizes the lateral dimensions and internal cavity space for fitting anchoring. The cover profiles attach to the external surfaces while fittings anchor into the internal structure, allowing both functions to operate independently in different spatial dimensions.

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

The solution provides high thermal insulation, dimensional stability, and a watertight seal, accommodating different materials while mitigating thermal expansion issues and ensuring seamless coverage and efficient water management.

Implementation Method 1

profiles made of thermoplastic, weldable material

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

different thermal expansion coefficients between the frame, which is e.g. made of PVC, and the cover profiles, which are e.g. made of aluminium

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2594720B2Window and door frames that can be covered with various materials made of thermoplastic, weldable material
Publication Date: 2019.12.25 FINSTRAL
  • EP2594720B2 patent drawingFigure 1~1b
  • EP2594720B2 patent drawingFigure 1c~2a
  • EP2594720B2 patent drawingFigure 3~4a

AI summary

The frame has suspension longitudinal bars (1b, 2b) and/or longitudinal grooves with inner suspension projections (2d) for fastening covering sections (10, 10a, 20, 20b) and/or strips of different material. The covering sections are connected by connection brackets (10v, 10w, 20v, 20w, 10x) to form a stable cover frame. One of the suspension bars are milled at profiles (2a) of a leaf frame (2) and a longitudinal bar (1c) at profiles (1a) of a stick frame (1). Longitudinal bars (10b, 10c, 20a) are milled at the covering sections in four corner regions of the frames.