Screen assembly for a window or door opening
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Solution Overview
Problem
Horizontally moving screen assemblies face challenges in maintaining a flat appearance due to sagging, as they are unsupported at the bottom edge and experience increasing tension issues when extended, leading to difficulty in operation and potential damage to the screen material.
Innovation Solution
A screen assembly with a tension equalizer, where the screen material is cut or formed to provide equivalent tension across longitudinal zones, and edge members are designed to maintain a straight top and bottom edge, using a combination of pulleys and biasing means to ensure uniform tension and prevent sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the screen material is supported only at two vertical edges for horizontally moving screens, then the screen can be rolled onto and off a support, but the screen material sags under gravity and loses its flat appearance
Solution Approach 1:
The screen material is divided into multiple longitudinal zones with individual tensioning mechanisms. Each zone can be independently tensioned to counteract sagging while maintaining the overall flat appearance of the screen when extended.
Solution Approach 2:
The screen material is pre-tensioned in multiple longitudinal zones before being extended. This preliminary tensioning action ensures that the screen maintains its flat appearance and resists sagging under gravity when deployed horizontally.
2Shape
If tension is increased to maintain a flat appearance, then the screen material stays taut, but the screen becomes difficult to operate and may suffer damage
Solution Approach 1:
The tensioning system is designed to be dynamic rather than static. The tension in each longitudinal zone can be adjusted and varies during operation, providing sufficient tension to maintain flat appearance when extended while reducing tension to ease operation when retracted.
Solution Approach 2:
The tension parameters in the screen material are changed dynamically during operation. The system adjusts the magnitude of tension applied to each longitudinal zone based on the screen's position and operational state, optimizing both appearance and ease of operation.
3Area of stationary object
If the screen material is extended across large openings, then the coverage area increases, but the tension becomes uneven across longitudinal zones causing sagging
Solution Approach 1:
The screen material is segmented into multiple longitudinal zones, each with its own tensioning mechanism. This segmentation allows independent control of tension in each zone, ensuring uniform tension distribution across the entire large opening regardless of the screen's extended position.
Solution Approach 2:
The tensioning system incorporates feedback mechanisms that monitor and adjust the tension in each longitudinal zone. This feedback ensures that tension remains uniform across all zones even when the screen is extended across large openings, preventing sagging and maintaining stability.
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 maintains a flat appearance and reduces sagging, allowing for easier operation and minimizing material damage by ensuring uniform tension across the screen, even in large spans.
Implementation Method 1
a tension equalizer, where the screen material is cut or formed to provide equivalent tension across longitudinal zones
Implementation Method 2
using a combination of pulleys and biasing means to ensure uniform tension and prevent sagging
Data Source
AI summary
A flexible screen material can be cut out of square, or part of the screen frame can be formed out of square such that when the screen is fitted to the screen frame, there is less sagging.