Dual-Curved Leaf Spring for Durable Retractable Screens

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Solution Overview

Problem

Existing retractable screen constructions face issues with durability and fatigue due to single curved regions in leaf springs, leading to torsional forces, manufacturing complexity, and environmental wear, especially in outdoor conditions.

Innovation Solution

A leaf spring design with at least two curved regions oriented perpendicularly to the screen guide and support, featuring a Z-shaped or S-shaped configuration, reduces fatigue by distributing load and providing optimal force transfer, enhancing durability and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a retractable screen is provided with a housing and a screen supported by a roller mechanism, then the screen can be retracted into the housing, but the housing protrudes from the plane of the opening and occupies valuable wall space

Engineering Contradiction:
Improvescreen retraction capabilityVSAvoidwall space occupied by housing
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The screen is nested within the roller mechanism, which is in turn nested within the housing. The roller mechanism allows the screen to be stored compactly inside the housing, enabling the housing to fit within a minimal protrusion distance from the wall opening while maintaining full screen functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Shape

If the screen is pulled taut during retraction, then the screen maintains a neat appearance, but the force required to operate the screen increases

Engineering Contradiction:
Improvescreen tautness and appearanceVSAvoidoperating force on screen
Core Design Contradiction:
ShapeVSForce

Solution Approach 1:

The roller mechanism is designed to dynamically adjust the tension on the screen during retraction. The screen is pulled taut only to the extent necessary for aesthetic appearance, with the roller mechanism accommodating variations in tension to maintain a neat appearance while keeping operating forces at acceptable levels.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4558695B1A retractable screen construction
Publication Date: 2026.04.29 CORRADI
  • EP4558695B1 patent drawingFigure 1
  • EP4558695B1 patent drawingFigure 2A~2B
  • EP4558695B1 patent drawingFigure 3A~3B

AI summary

A retractable screen construction (1) comprising: comprising: a support; a screen guide located in the support; a retractable screen (4) having a lateral side guided in the screen guide; and a leaf spring to tension the screen. The leaf spring comprises a connection region extending between regions where the leaf spring engages the support and the screen guide. The connection region comprises first and second curved region which curves in opposite rotational direction, wherein a hypothetical cylinder tangential to either one of the curved regions extends in a direction perpendicular to the screen. By providing at least two curved regions with a different curvature direction, the amount of deformation of each curved region in order to account for the dynamic load exerted by the screen is reduced, leading to an improved durability of the leaf spring.