Roof Window Base Frame Module with Stepped Corner Connections

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Solution Overview

Problem

Conventional roof window frames face issues with unfavorable shear stress due to snow loads, difficulty in connecting frame sections with different cross-sections, and inadequate condensation drainage, especially in closed frame shells.

Innovation Solution

A base frame module with longitudinal and transverse legs featuring projecting and recessed sections for corner connections, allowing easy assembly and improved force absorption, along with integrated drainage channels to manage condensate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional miter joint connections are used for frame sections, then assembly is simple and frames form a closed shell, but the fasteners are subjected to unfavorable shear stress under snow loads

Engineering Contradiction:
Improveforce absorption at corner connectionsVSAvoidshear stress on fasteners
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The corner connection is segmented into a recessed section and a projecting section, allowing the frame legs to be divided into functional zones that distribute mechanical loads differently, reducing shear stress on fasteners

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection transitions from a planar miter joint to a three-dimensional stepped configuration with recessed and projecting sections, enabling force distribution in multiple directions and reducing shear stress concentration

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

2Adaptability or versatility

If frame sections with different cross-sections are connected using conventional methods, then connection is difficult and requires considerable effort, but the frame can accommodate various design requirements

Engineering Contradiction:
Improveconnection of different cross-sectionsVSAvoidassembly effort
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The recessed section and projecting section design creates a universal connection interface that can accommodate frame legs with different cross-sections, allowing the same connection mechanism to work across various design configurations

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

Solution Approach 2:

By segmenting the connection into recessed and projecting sections, the design allows different cross-sections to be joined through a standardized interface, reducing assembly complexity while maintaining adaptability

Inventive Principle:
Principle #1Segmentation

3Strength

If frame sections are connected to form a closed frame shell, then structural integrity is improved, but condensation drainage becomes difficult and requires well-sealed joints

Engineering Contradiction:
Improvestructural integrity of frameVSAvoidcondensation drainage
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The frame connection is segmented into recessed and projecting sections that create distinct functional zones, allowing the joint area to serve both structural and drainage functions simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recessed section acts as an intermediary element between connecting frame legs, providing a built-in drainage pathway that mediates between the need for structural integrity and condensation removal

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4435195B1Base frame module for roof window
Publication Date: 2025.10.15 LAMILUX HEINRICH STRUNZ
  • EP4435195B1 patent drawingFigure 1~2
  • EP4435195B1 patent drawingFigure 3~4
  • EP4435195B1 patent drawingFigure 5a~6

AI summary

The invention relates to a base frame module for roof windows, comprising: a longitudinal leg and a transverse leg, which are arranged substantially at right angles to each other and are connected substantially at right angles to each other at one end region; wherein the longitudinal leg and the transverse leg each have a projecting section and a recessed section at the connected end regions; wherein the recessed section of the longitudinal leg abuts a lateral region of the projecting section of the transverse leg at its end face; and wherein the recessed section of the transverse leg abuts a lateral region of the projecting section of the longitudinal leg at its end face.