Extensible Screen Cord System for Variable Light Permeability

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Solution Overview

Problem

Existing window screening arrangements, such as roller blinds, are difficult to adjust for light intake and are not suitable for windows installed at angles or inclined roofs, as they rely on gravity and weight for tensioning, which limits their installation flexibility and control over light and heat permeability.

Innovation Solution

A screening arrangement with a cord system and spring device that provides pre-tensioning to maintain the extensible screen in a stretched state during unwinding, allowing for adjustable light and heat control, suitable for various window orientations, including inclined roofs, through a cord system with traction cords connected to a roller shaft and a spring device integrated into the bottom bar or side rails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a roller blind with fabric screen is used, then light intake can be adjusted by varying covering length, but the ability to control light permeability is limited and adjustment is difficult

Engineering Contradiction:
Improvelight intake controlVSAvoidadjustment difficulty
Core Design Contradiction:
Illumination intensityVSEase of operation

Solution Approach 1:

The patent applies parameter changes by transforming the screen material from a static fabric to an extensible material with variable aperture size. The apertures can be dynamically adjusted between open and closed states, changing the optical parameters of the screen to control light permeability directly rather than just adjusting covering length.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The screening arrangement introduces dynamic control through motor-driven mechanisms that can open and close the apertures in the extensible screen. This allows real-time adjustment of light permeability during operation, transforming a static blind into a dynamically controllable screening system.

Inventive Principle:
Principle #15Dynamics

2Force

If gravity-based tensioning is used in roller blinds, then the screen can be tensioned, but the arrangement is unsuitable for inclined roofs and horizontal windows

Engineering Contradiction:
Improvescreen tensioningVSAvoidinstallation position flexibility
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The patent replaces gravity-based tensioning with an active tensioning system that uses motor-driven rollers to apply controlled force to the extensible screen. This counteracts the limitation of gravity-dependent systems, allowing the screen to be properly tensioned in any orientation including inclined roofs and horizontal windows.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The invention substitutes the passive mechanical gravity-based tensioning system with an active electromechanical tensioning system. The motor-driven rollers provide controlled tensioning force that is not dependent on gravitational direction, enabling versatile installation in various orientations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Illumination intensity

If an extensible screen with variable aperture is used, then light permeability control is improved, but the screen requires continuous tensioning to maintain stretched state

Engineering Contradiction:
Improvelight permeability controlVSAvoidtensioning requirement
Core Design Contradiction:
Illumination intensityVSForce

Solution Approach 1:

The patent implements continuous tensioning through the motor-driven roller system that maintains constant force application to the extensible screen. This ensures the screen remains in a stretched state with controlled apertures throughout operation, preventing slack and maintaining optimal optical performance continuously.

Inventive Principle:
Principle #20Continuity of useful action

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 improved control over light and heat permeability in a wide range of window installations, including inclined roofs, by maintaining tension in the screen and accommodating surplus cord length, ensuring proper functioning and adjustable light intake.

Implementation Method 1

a spring device (5) to provide pre-tensioning of the at least one traction cord (3)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3385493B1Screening arrangement with extensible screen and method for providing variable screening of a window
Publication Date: 2020.01.01 VKR HOLDING AS
  • EP3385493B1 patent drawingFigure 1
  • EP3385493B1 patent drawingFigure 1a
  • EP3385493B1 patent drawingFigure 2

AI summary

The screening arrangement (100) provides for adjustment of the light intake of a window, by providing an extensible screen (6) with variable permeability such that when traction is applied, the permeability of the material is increased. A roller shaft (1) is connected to drive means and traction means are provided to apply a traction force on the extensible screen (6) to bring the extensible screen (6) to a first stretched state in which the permeability of the material is increased, corresponding to a first screening position. From the first screening position, the extensible screen (6) is brought to a second screening position in which the extensible screen (6) is in a second stretched state by continued rotation of the roller shaft (1) in the unwinding direction. The permeability of the extensible screen (6) is decreased in the second stretched state relative to the first stretched state. According to the invention, the traction means comprises a cord system including at least one traction cord (3) in connection with the roller shaft (1) and the extensible screen (6). A spring device (5) provides pretensioning of the traction cord (3), the cord system being configured to apply a traction force on the extensible screen (6) such that the tension exerted by the cord system on the extensible screen (6) provides said first stretched state during unwinding of the extensible screen (6).