Window Screening Cord Tension Adjustment via Break-Off Rails

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Solution Overview

Problem

Conventional window screening arrangements are not adaptable to different window sizes, requiring specific sizes and often complicated installation processes, which can lead to improper cord tension and installation difficulties.

Innovation Solution

The screening arrangement features side rails with weakening portions for adjustable lengths and a cord system with a tortuous path for length adjustment, allowing the same side rail to fit multiple installation positions while maintaining proper cord tension, facilitated by a cord adjustment unit with a receiving fitting and cord holder that can be easily connected to the frame and side rail.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the cord is shortened by cutting or knotting to fit different window sizes, then the cord length is adjusted, but the cord tension cannot be properly maintained and installation becomes irreversible

Engineering Contradiction:
Improveadaptability to different window sizesVSAvoidcord tension maintenance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The cord adjustment device enables dynamic adjustment of cord length through a winding mechanism with movable winding elements and locking elements. The cord can be adjusted to different lengths and the tension maintained through the spring mechanism and locking system, allowing reversible adaptation to different window sizes while preserving proper cord tension.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the cord is wound onto an axle to adjust length, then the cord length can be adjusted, but the mounting process becomes troublesome and requires specific cord tension

Engineering Contradiction:
Improvecord length adjustmentVSAvoidinstallation ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The cord adjustment device is designed to be self-contained within the side rail structure, with the winding mechanism integrated into the existing components. The device automatically maintains proper cord tension through the spring mechanism, eliminating the need for manual tensioning adjustments during installation.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If traditional screening arrangements are delivered in predetermined sizes, then each window requires a specific screening arrangement, but this increases device complexity and installation difficulty

Engineering Contradiction:
Improveprecise fit for specific window dimensionsVSAvoidvariety of sizes and types
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The side rail incorporates an integrated cord adjustment device that allows a single screening arrangement design to accommodate multiple window sizes. The break-off sections and adjustable cord mechanism enable one universal product to replace multiple size-specific products, reducing device complexity while maintaining precise fit.

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

Data Source

PatentEP2987944B1Screening arrangement comprising a cord system and cord length adjusting means
Publication Date: 2018.05.02 VKR HOLDING AS
  • EP2987944B1 patent drawingFigure 1
  • EP2987944B1 patent drawingFigure 2
  • EP2987944B1 patent drawingFigure 3

AI summary

A screening arrangement (1) for a window adapted to be mounted in a frame (2) of the window, having a supply condition and a mounted condition including at least two installation positions, the screening arrangement comprising a screening body (6) and two side rails (8, 9) each defining a longitudinal direction between a lower end (818) and an upper end (819) and having a predefined length corresponding to a first installation position, the side rails (8, 9) each being configured to form a break-off section (8a) and a remaining section (8b) for providing at least one adjusted length corresponding to a respective at least one other installation position, the adjusted length being shorter than the length of the side rail (8, 9) in the first installation position, the screening arrangement (1) further comprising at least one cord system having a cord (410) for guiding the screening body (6) between a screening position and a non-screening position.