Double-Wing French Window Closure Mechanism Without Central Mullion

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Solution Overview

Problem

Existing window door closures for double-leaf doors without a mullion couple locking and snapping functions, limiting the ability to disable bolt movement to the locked position and complicating operation when the active leaf is open.

Innovation Solution

The design separates the bolt and catch into independent components, with a guide element featuring ramps for pin movement in two directions, allowing the bolt to be controlled by the active leaf's position and the catch to hold the passive leaf non-positively, enabling easy opening and closing regardless of the active leaf's position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the locking and snapping functions are coupled together in a single bolt mechanism, then the structure is simpler with fewer components, but the ability to independently control bolt movement is lost and operation becomes more difficult when the active leaf is open

Engineering Contradiction:
Improvestructure simplicityVSAvoidoperation convenience
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The closure mechanism is divided into two independent functional components: a bolt for locking and a catch for snapping. This segmentation allows each component to perform its specific function independently, enabling the bolt to be controlled separately from the catch mechanism, thus improving operational convenience while maintaining structural simplicity through functional decomposition

Inventive Principle:
Principle #1Segmentation

2Reliability

If the bolt is prestressed into the locking position by a spring element with a latch bevel, then reliable locking is achieved when the active leaf is closed, but the bolt cannot be manually removed when the active leaf is open due to the spring force

Engineering Contradiction:
Improvelocking reliabilityVSAvoidmanual removal capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The prestressing spring element and latch bevel are extracted from the bolt mechanism and transferred to the catch component. This allows the bolt to be freely movable and manually removable when the active leaf is open, while the catch maintains reliable holding function through its own spring element and bevel geometry, thus resolving the contradiction between locking reliability and manual removal capability

Inventive Principle:
Principle #2Taking out (Extraction)

3Quantity of substance

If a single bolt performs both locking and snapping functions, then the number of components is reduced, but the passive leaf cannot be easily moved when the active leaf is open due to the coupled mechanism

Engineering Contradiction:
Improvenumber of componentsVSAvoidleaf movement ease
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The closure is segmented into separate bolt and catch components, each with independent actuation. The catch can be operated independently to move the passive leaf without requiring bolt movement, enabling easy leaf manipulation when the active leaf is open, while maintaining a minimal component count through functional specialization

Inventive Principle:
Principle #1Segmentation

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

This solution ensures reliable locking of the fixed leaf when the active leaf is closed and allows convenient operation by decoupling the locking and snapping functions, enabling easy opening and closing of the passive leaf with reduced structural effort and minimal components.

Implementation Method 1

the catch is pretensioned by a spring element into a protruding position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the guide element has two opposite ramps, which create a slotted guide for the pin, for moving the pin in two directions

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2821573B1Closure for a double-wing French window without central mullion
Publication Date: 2017.05.31 WINKHAUS
  • EP2821573B1 patent drawingFigure 1~2
  • EP2821573B1 patent drawingFigure 3~5

AI summary

A locking mechanism (6) for a double-leaf French door without a mullion has a bolt (9) for locking a fixed leaf (3) and a catch (10) sandwiched over the bolt (9) for positively locking the fixed leaf (3) to a frame (1). The bolt (9) is integrally formed with a release element (14) that is displaceable by the movement of an active leaf (2). This ensures that the fixed leaf (3) is reliably locked when the active leaf (2) is closed. When the active leaf (2) is open, the fixed leaf (3) is unlocked and positively locked in the closed position.