Twin Casement Frame With V-Shaped Welded Mullion-Seal Joint

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Solution Overview

Problem

Existing window and door frames with transoms and mullions that open in opposite directions face difficulties in sealing due to the offset of connected rod sections and springing, leading to unsatisfactory welds and sealing grooves.

Innovation Solution

A one-piece rod design with V-shaped lintel receiving recesses and tapered welding surfaces allows for a secure, form-fitting engagement and seamless integration of seals, eliminating the need for Z-welding and simplifying the weld finishing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Z-welding with two separate mullion sections is used to create a reversible mullion, then the mullion can support windows opening in opposite directions, but the offset of connected rod sections makes plastering very difficult or impossible

Engineering Contradiction:
Improvereversible mullion functionalityVSAvoidplastering difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The mullion is divided into two sections with different overlap orientations (one on visible side, one on rear side) to enable reversible window operation, while the transom is made as a single continuous piece to provide a smooth plasterable surface

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The offset problem is extracted and resolved by making the transom a single continuous piece that spans across the mullion joint, eliminating the offset issue at the plasterable surface while maintaining the segmented mullion structure underneath

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If a completely butt-welded connection of the springing is used, then the connection is simple, but sealing grooves lead to unsatisfactory results

Engineering Contradiction:
Improvewelding simplicityVSAvoidsealing performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The transom has different structural characteristics at different locations: a V-shaped recess with tapered welding surfaces at the ends for secure connection, and a continuous smooth profile in the middle section for proper sealing groove formation and plastering

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The V-shaped recesses with tapered welding surfaces are pre-formed in the transom before assembly, enabling secure form-fitting engagement and proper sealing groove alignment without requiring complex field adjustments

Inventive Principle:
Principle #10Preliminary action

3Reliability

If V-shaped lintel receiving recesses with tapered welding surfaces are used, then form-fitting engagement and seal integration are improved, but the manufacturing complexity increases

Engineering Contradiction:
Improveconnection securityVSAvoidmold complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The transom profile includes V-shaped recesses with specific tapered angles (matching the 45° chamfer angle of the mullion welding surfaces) that provide form-fitting engagement and secure welding, while the continuous profile ensures proper sealing groove formation

Inventive Principle:
Principle #35Parameter changes

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 improved sealing and aesthetic integration of seals, simplifies welds, and ensures secure connections without the need for Z-welding, enhancing the overall structural integrity and appearance of the frame.

Implementation Method 1

heating of the bar-side welding surfaces and/or the transom-side welding surfaces

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

pressing of the bar-side welding surfaces and the transom-side welding surfaces against each other for a material- and form-fitting connection

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP4700203A1Twin casement frame with reverse-butt and method
Publication Date: 2026.02.25 URBAN
  • EP4700203A1 patent drawingFigure 1
  • EP4700203A1 patent drawingFigure 2
  • EP4700203A1 patent drawingFigure 3

AI summary

A frame (2) is proposed, comprising at least one rod (10) with a visible side (S10) and a rear side, and a springer (20) with a visible side (S20) and a rear side (R20) connected to the rod (10), wherein the rod (10) has a visible longitudinal edge (11a) and a V-shaped springer receiving recess (12) with welding surfaces (13), wherein the springer (20) has a visible end edge (21a) and two V-shaped tapered welding surfaces (23) which together define a springer tip (22), wherein the visible longitudinal edge (11a) abuts the visible end edge (21a), and wherein the rod-side welding surfaces (13) are connected to the springer-side welding surfaces (23).