Plastic Fastening Channel Interlock for Window Profile Pull-Out Force

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Solution Overview

Problem

Existing extruded window or door hollow chamber profiles experience side walls receding from each other when a fastening bolt is inserted, especially when end walls are far apart or side walls are flexible due to thickness or material, resulting in low pull-out forces.

Innovation Solution

Incorporating a fastening channel made entirely of plastic, laterally delimited by chamber side walls with a distance less than the fastening bolt's outer diameter, and optionally featuring intermediate webs, different wall thicknesses, or curved side walls to ensure interlocking with the fastening bolt over its length, enhancing pull-out force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the end walls are at a large distance from one another or the side walls are made flexible with smaller wall thickness, then the fastening channel can accommodate larger fastening bolts, but the side walls recede from each other when the fastening bolt is inserted, reducing pull-out force

Engineering Contradiction:
Improvedistance between end wallsVSAvoidpull-out force
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The patent introduces intermediate webs that divide the fastening channel into multiple segments along its length. These intermediate webs prevent the side walls from receding when the fastening bolt is inserted, while still allowing the end walls to be at a large distance apart. The segmentation creates multiple restraint points that maintain side wall spacing throughout the channel length.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different wall thicknesses to different portions of the fastening channel. The side walls have reduced thickness in specific regions to allow bolt insertion and interlocking, while intermediate webs or reinforcement elements are strategically placed to prevent excessive deformation. This localized variation in wall thickness optimizes both accommodation of large bolts and prevention of side wall recession.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the side walls are made thinner or from flexible material, then the fastening channel can be manufactured more easily and costs are reduced, but the side walls recede when the fastening bolt is inserted, resulting in low pull-out forces

Engineering Contradiction:
Improvemanufacturing of fastening channelVSAvoidpull-out force
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

By introducing intermediate webs that segment the fastening channel, the patent enables the use of thinner, more flexible side wall materials without compromising structural integrity during fastening. The intermediate webs provide internal support that prevents side wall recession, allowing manufacturers to use cost-effective thin-walled extrusion profiles while maintaining high pull-out forces through the segmented reinforcement strategy.

Inventive Principle:
Principle #1Segmentation

3Strength

If the distance between side walls is made less than the fastening bolt diameter for interlocking, then high pull-out force is achieved, but the fastening channel becomes more complex and harder to manufacture

Engineering Contradiction:
Improvepull-out forceVSAvoidfastening channel structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the fastening channel structure with intermediate webs that are integrated into the extrusion profile. Rather than adding separate reinforcement components, the intermediate webs are formed as part of the same extrusion process, creating a unified structure that achieves both side wall spacing control and manufacturing efficiency. This merging reduces overall device complexity while maintaining the interlocking capability for high pull-out forces.

Inventive Principle:
Principle #5Merging (Combining)

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 pull-out forces, meeting burglar-proof specifications, by ensuring the fastening bolt interlocks with the plastic channel over its entire length, preventing side walls from receding and maintaining structural integrity.

Implementation Method 1

the edge profile of the fastening bolt works its way into the side walls of the chamber. This is preferably done over the entire length of the chamber side walls adjacent to the fastening bolt. This ensures good interlocking of the plastic fastening channel with the fastening bolt over its entire length

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Implementation Method 2

By curving the side walls, the fastening channel is prestressed towards the fastening bolts when the fastening bolts are inserted. This preload counteracts the side walls moving away from the fastening bolt.

Methodology Applied
Scientific EffectPrestress: Elasticity

Data Source

PatentEP2079895B1Extruded hollow chamber profile for windows or doors
Publication Date: 2015.09.30 REHAU AG & CO
  • EP2079895B1 patent drawingFigure 1~3
  • EP2079895B1 patent drawingFigure 4~7

AI summary

An extruded hollow chamber profile (1) for windows or doors has at least one fastening zone (2) for fastening the hollow chamber profile (1) on or to an external component (3). The fastening zone (2) has a fastening bolt (4) with profiled edges. A plastic fastening channel (8) having a channel longitudinal axis (9) for insertion of the fastening bolt (4) along the fastening channel (8) extends transversely to a direction of extrusion (7) of the hollow chamber profile (1). The fastening channel (8) is delimited by two chamber sidewalls (10, 11) at a right angle to the channel longitudinal axis (9), the distance (A) of said walls in relation to each other being smaller than the outer diameter (Da) of the fastening bolt (4). In the direction of the channel longitudinal axis (9), the fastening channel (8) is delimited by two chamber faces (12, 13) through which the fastening bolt (4) is guided. At least one fastening hollow chamber (14) is formed between the channel sidewalls (10, 11) and channel faces (12, 13). The hollow chamber profile according to the invention allows a high withdrawal force of the fastening bolt (4) even if the latter is not guided through a metal wall.