PVC Window Frame with Undercut Facing Shell Attachment

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Solution Overview

Problem

Existing profile systems for windows and doors face challenges such as increased depth due to aluminum facing shells, high production costs for special casement profiles, limited tolerance accommodation, and incompatibility with post-coextruded seals, restricting design freedom and efficiency.

Innovation Solution

A frame system using hard PVC (PVC-U) frame profiles welded in the miter area, with coextruded or post-coextruded seals, and aluminum attachment profiles featuring undercuts and elastic deformable fastening means that allow form-fitting attachment without increasing frame depth, accommodating various tolerances, and using standard PCE seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If facing shells are attached to frame profiles using conventional clipping methods, then aesthetic appearance is improved, but frame depth is increased considerably

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidframe depth
Core Design Contradiction:
ShapeVSLength of stationary object

Solution Approach 1:

The facing shell profile is inserted into a receiving groove formed by the interaction of a groove-shaped undercut on the facing shell and a corresponding protrusion on the frame profile, creating a nested structure where the facing shell is received within the frame profile structure without adding external depth

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of attaching the facing shell from the external surface (adding depth in one dimension), the invention uses a receiving groove mechanism that engages in the cross-sectional plane, allowing the facing shell to be attached without increasing the external dimensions of the frame

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

2Reliability

If special casement profiles with groove-shaped undercuts are used for facing shells, then form-fitting attachment is achieved, but production costs increase due to high investments

Engineering Contradiction:
Improveform-fitting attachmentVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The frame profile is designed with a receiving groove structure that can accommodate both facing shells and glazing seals using the same groove-shaped undercut mechanism, allowing a single profile design to serve multiple functions and eliminating the need for separate special casement profiles

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

Solution Approach 2:

The invention combines the functions of the facing shell attachment and the glazing seal retention into a single receiving groove structure, merging two separate attachment mechanisms into one integrated system that reduces manufacturing complexity

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If facing shell profiles with bevels or hook-shaped projections are used, then simple construction is achieved, but tolerance accommodation is limited

Engineering Contradiction:
Improveconstruction simplicityVSAvoidtolerance accommodation
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The receiving groove is designed with dimensional parameters that accommodate tolerance variations, allowing the groove-shaped undercut and corresponding protrusion to engage effectively across a range of dimensional deviations while maintaining simple construction

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If conventional clipping methods are used for facing shells, then assembly is simple, but compatibility with post-coextruded seals is lost

Engineering Contradiction:
Improveassembly simplicityVSAvoidseal compatibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The receiving groove structure serves dual purposes: it attaches the facing shell and simultaneously provides a seat for the post-coextruded seal, allowing the same simple clipping mechanism to work with standard PCE seals without requiring special seal designs

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

Enables slim, flat, and efficient assembly of frames with commercially available facing shells, compensating for dimensional deviations, and maintaining compatibility with standard PCE seals, thus enhancing design flexibility and assembly simplicity.

Implementation Method 1

elastically deformable fastening means which are fastened to the upper visible surface areas of the overlaps of the frame profiles, which spring back behind the undercuts of the front profiles during the installation of the front profiles

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

frame profiles made of hard PVC (PVC-U) that are welded to one another in the miter area

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3581751B1Frame with a facing shell and method for producing the same
Publication Date: 2020.11.11 PROFINE GMBH
  • EP3581751B1 patent drawingFigure 1
  • EP3581751B1 patent drawingFigure 2~5

AI summary

In the case of a profile system or a composite frame (2) with a cover shell (5), a system for manufacturing a frame (2) for a window (4) or a door with a cover shell (5) is proposed, in which - the frame profiles (1) are extruded from rigid PVC (PVC-U) and welded together in the miter area to form the frame (2), - the frame profiles (1) have an outer visible surface (7), a rebate area (8) and an outer overlap (9) limiting the rebate area (8), - the overlap (9) of the frame profiles (1) has an upper visible surface area (11) inclined towards the glazing plane A in cross-section and a seal (12);- the cover profiles (6) have an outer visible surface (13) and an inner surface (14), - the cover profiles, when mounted, at least partially cover the outer visible surfaces (7) of the frame profiles (1) and completely cover the upper visible surface areas (11) inclined towards the glazing plane A, - the cover profiles (6) have an undercut (16) on their inner surfaces (14) and the upper visible surface areas (11) of the overlaps (9) of the frame profiles (1) have bores (22) into which deformable fasteners (17, 17', 17") are inserted, which, when the cover profiles (6) are mounted, project behind the undercuts (16) of the cover profiles (6) and thus effect a positive locking fastening of the cover profiles (6) to the frame profiles (1).;