Retractable Screen Latch Mechanism for Weatherproof Locking

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Solution Overview

Problem

Existing retractable screen systems face durability issues due to exposure of guide paths to atmospheric conditions, leading to blockages and malfunctions, and resilient elements suffer wear and tear, affecting the reliability of automatic locking and unlocking mechanisms.

Innovation Solution

A latch mechanism using a rototranslatable lever guided in a labyrinth member, eliminating the need for resilient elements and ensuring accurate positioning of the latch bolt between depressed, retracted, and extended positions, while being enclosed to protect against atmospheric interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If guide paths are exposed to the outside atmosphere for automatic locking and unlocking functionality, then the screen can be automatically tensioned, but precipitation and dirt can enter and block the guide paths causing malfunctions

Engineering Contradiction:
Improveautomatic locking and unlockingVSAvoidguide path blockage resistance
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The guide paths are nested within the enclosed space of the draw bar, specifically housed in a recessed area. This nesting protects the guide paths from direct exposure to atmospheric conditions while still allowing the latch bolt to move through them for automatic locking and unlocking functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The draw bar provides an enclosed housing that acts as a protective shell around the guide paths. This enclosure prevents precipitation and dirt from directly contacting the guide paths, while the system maintains functionality through the enclosed space.

Inventive Principle:
Principle #30Flexible shells and thin films

2Extent of automation

If resilient elements are used in the locking mechanism to enable automatic locking, then the latch bolt can cycle through positions, but the resilient elements suffer wear and tear affecting durability

Engineering Contradiction:
Improveautomatic lockingVSAvoidlocking mechanism durability
Core Design Contradiction:
Extent of automationVSDuration of action of stationary object

Solution Approach 1:

The invention extracts and eliminates the resilient element from the locking mechanism. Instead of using a spring or elastic component to return the latch bolt to its initial position, the system uses the weight of the draw bar itself and the geometry of the guide paths to achieve the same functional result, thereby removing the source of wear and tear.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the resilient element-based mechanical system with a gravity-based mechanical system. The weight of the draw bar provides the forcing function to move the latch bolt through its cycle, eliminating the need for elastic components and their associated wear problems.

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

3Extent of automation

If the latch bolt is exposed to the outside atmosphere for automatic locking, then the screen can be automatically tensioned, but outside exposure can interfere directly with the latch bolt causing malfunctions

Engineering Contradiction:
Improveautomatic lockingVSAvoidatmospheric interference with latch bolt
Core Design Contradiction:
Extent of automationVSObject-affected harmful factors

Solution Approach 1:

The latch bolt is nested within the enclosed space of the draw bar, moving through guide paths that are protected from direct atmospheric exposure. This nesting protects the latch bolt from precipitation and dirt while still allowing it to perform its locking function.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The draw bar enclosure acts as a protective shell that isolates the latch bolt from harmful atmospheric factors. The enclosed space prevents direct contact with precipitation and dirt, reducing malfunctions while maintaining automatic locking capability.

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enhances durability and reliability by preventing pathway blockages and reducing wear, maintaining automatic locking and unlocking functionality without relying on resilient elements, thus improving the longevity and performance of retractable screens.

Implementation Method 1

a biasing member (11) urging the latch bolt (10) towards its extended position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

rotatable about a pivot axis perpendicular to the longitudinal direction

Methodology Applied
Scientific EffectRotation:

Implementation Method 3

water flow caused by gravity will, over time, deposit filth therein

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4453368B1A retractable screen construction
Publication Date: 2026.02.04 CORRADI
  • EP4453368B1 patent drawingFigure 1
  • EP4453368B1 patent drawingFigure 2
  • EP4453368B1 patent drawingFigure 3B~3a

AI summary

A retractable screen construction comprising: a retractable screen having a draw bar extending in a longitudinal direction and a locking assembly to lock the draw bar in a fixed position. The locking assembly comprises a stationary keeper and a latch mechanism disposed inside the draw bar. The latch mechanism comprises: a latch bolt which is slideable along the longitudinal direction between a depressed position, a retracted position and an extended position; a biasing member urging the latch bolt towards its extended position; a rototranslatable lever on which the latch bolt is pivotally mounted and having two cam members, the rototranslatable lever being slideable along the longitudinal direction and rotatable about a pivot axis perpendicular to the longitudinal direction; and a labyrinth member having a plurality of pathways in which said two cam members are guided. The rototranslatable lever is cyclically moveable allowing automatic locking/unlocking of the draw bar.