Pivotable Darkening Element for Skylight Gap Sealing

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Solution Overview

Problem

Existing darkening devices for skylights, such as blackout blinds, face challenges in completely darkening the window opening due to variable gaps between the curtain and the cassette, allowing light to pass through, especially in the darkening position where the curtain is unwound, leading to unwanted solar radiation.

Innovation Solution

A pivotably mounted, elastically variable darkening element that adapts to the gap between the curtain and the cassette, ensuring reliable darkening by expanding to match the gap in the darkening position and minimizing friction during winding and unwinding, which can be driven by gravity or a spring for easy movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the curtain is unwound from the winding shaft in the darkening position, then the curtain can effectively block light, but a large gap forms between the wound curtain and the inside of the cassette, allowing light to pass through

Engineering Contradiction:
Improvelight passage through gapVSAvoiddarkening effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

A darkening element is introduced as an intermediary component between the curtain and the cassette. This element is pivotably mounted and can be positioned to close the gap that forms when the curtain is unwound, preventing light from passing through while not interfering with the curtain's primary light-blocking function

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The darkening element is designed to be pivotably mounted rather than fixed, allowing it to dynamically adjust its position. It can rotate between a retracted state (when the curtain is wound) and an advanced state (when the curtain is unwound) to actively close the varying gap, ensuring continuous light blocking effectiveness

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If a fixed darkening element is used to cover the gap, then light passage can be prevented, but the device complexity increases and friction during winding/unwinding increases

Engineering Contradiction:
Improvelight passage preventionVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The darkening element is pivotably mounted to enable dynamic adjustment between retracted and advanced positions. This dynamic design allows the element to adapt to different curtain positions without requiring complex mechanical structures, maintaining simplicity while effectively preventing light passage

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The darkening element is designed to move automatically based on the curtain's position. When the curtain is unwound, gravity or elastic force causes the darkening element to pivot into the advanced state to close the gap, and when the curtain is wound, it automatically returns to the retracted state, eliminating the need for additional actuators or complex control mechanisms

Inventive Principle:
Principle #25Self-service

3Reliability

If a heavy darkening element is used to ensure reliable gap coverage, then darkening effectiveness improves, but the friction during winding and unwinding increases and operation becomes difficult

Engineering Contradiction:
Improvegap coverage reliabilityVSAvoidwinding and unwinding ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

An elastic element is introduced to counterbalance the weight of the darkening element. The elastic force opposes gravity, allowing the darkening element to be lighter while still reliably moving to the advanced state when needed. This reduces friction during operation and makes winding and unwinding easier

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

Solution Approach 2:

The darkening element is pivotably mounted to enable dynamic adjustment between retracted and advanced positions. This dynamic design allows the element to adapt to different curtain positions without requiring complex mechanical structures, maintaining simplicity while effectively preventing light passage

Inventive Principle:
Principle #15Dynamics

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 effectively prevents light from passing through the gap, ensuring complete blackout with a simple and durable structure, maintaining low friction and easy operation, and can be easily manufactured and integrated into the upper profile of the cassette.

Implementation Method 1

the darkening element is elastically variable between a compressed state, in which the expansion of the darkening element in a direction transverse to the winding shaft corresponds to the gap in the open position, and an expanded state, in which the expansion of the darkening element in the transverse direction to the winding shaft corresponds to the gap in the darkening position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the darkening element is pivotably mounted and rests on the curtain wound onto the winding shaft due to gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3409876B1Darkening device
Publication Date: 2020.03.25 HUNTER DOUGLAS INDUSTRIES SWITZERLAND GMBH
  • EP3409876B1 patent drawingFigure 1
  • EP3409876B1 patent drawingFigure 2
  • EP3409876B1 patent drawingFigure 3~4

AI summary

In a blackout device (10) for darkening a window opening of a roof window (11) in a building, with a light-impermeable curtain (17) that can be wound onto a winding shaft (16) between a blackout position and an open position, and with a frame (12) which has an upper profile (13) designed as a cassette (13) for receiving the winding shaft (16), the opening can be darkened better and more completely if a blackout element (20) is provided for darkening a gap between the upper profile (13) and the curtain (17).