Pivoting Latch Locking Mechanism for Window Sash

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Solution Overview

Problem

Existing locking devices for swing shutters and similar applications require complex configurations and precise adjustments, making them unreliable due to variations in installation conditions and deformations over time, especially when using motorized drive systems.

Innovation Solution

A locking device with a latch pivotally mounted on the leaf, featuring a movable stop and retaining means that provide resistance to rotation, allowing the latch to be controlled from an unlocked to a locked position only when the leaf is fully closed, ensuring secure locking without the need for fine adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex locking mechanism with multiple components is used to ensure reliable locking, then the locking reliability improves, but the device complexity increases and requires precise adjustments that are difficult to maintain under varying installation conditions

Engineering Contradiction:
Improvelocking reliabilityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is divided into functionally independent segments: the latch assembly with its pivot axis, the movable stop with its own pivot axis, and the retaining means. This segmentation allows each component to perform its specific function independently, simplifying the overall design while maintaining reliability. The latch handles locking/unlocking, the movable stop controls timing, and the retaining means prevents premature engagement, eliminating the need for complex interconnections and precise adjustments between components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable stop is positioned in advance to block the latch's rotation path before the latch can reach the locked position. This preliminary blocking action prevents premature locking during the opening/closing motion. The stop's position is predetermined by its pivot axis and geometry, eliminating the need for field adjustments to timing. The retaining means also acts in advance by providing continuous resistance to rotation, ensuring the latch remains可控 until the proper moment.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the latch is directly controlled by the drive means without retaining means, then the device complexity decreases, but the latch may rotate prematurely or uncontrollably during leaf movement

Engineering Contradiction:
Improvemechanism simplicityVSAvoidlatch control reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The movable stop acts as an intermediary element between the latch and the drive means. Instead of the drive means directly controlling the latch, the stop mediates this control by physically blocking the latch's rotation path at inappropriate times. This intermediary mechanism ensures the latch only rotates to the locked position when the leaf is properly closed, providing reliable control without requiring complex feedback systems or multiple control components. The stop's geometry and pivot position automatically enforce the correct timing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The retaining means provides self-service by automatically providing resistance to the latch's rotation through its mechanical configuration. The elastic element continuously exerts force on the stop, which in turn resists the latch's rotation without requiring active control signals or additional energy input. The system uses the natural mechanical interactions between components to enforce proper latch control, eliminating the need for complex control systems while maintaining reliability.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If precise adjustments are required for proper locking operation, then the locking precision improves, but the ease of manufacture and installation deteriorates due to the need for fine-tuning under varying installation conditions

Engineering Contradiction:
Improvelocking precisionVSAvoidinstallation ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The movable stop is designed to pivot about its own axis, allowing it to dynamically adapt to variations in installation conditions. Rather than requiring precise fixed positioning, the stop's pivot mechanism enables it to self-adjust during operation. The elastic element provides continuous force to maintain the stop in its blocking position, compensating for manufacturing tolerances and installation variations. This dynamic design ensures reliable locking precision without requiring field adjustments.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the critical parameters from fixed geometric relationships to force-based interactions. The elastic element's force magnitude and direction automatically adjust to maintain proper latch control, compensating for variations in component dimensions and installation alignment. The movable stop's pivot position and blocking geometry work in conjunction with the elastic force to provide a tolerance-compensating mechanism that maintains locking precision across varying installation conditions without requiring precise initial setup.

Inventive Principle:
Principle #35Parameter changes

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 provides reliable locking without requiring precise adjustments, ensuring the latch remains in the unlocked position until the leaf is fully closed, then transitioning to a locked position securely, enhancing locking reliability and simplifying installation.

Implementation Method 1

a latch (6) pivotally mounted (10) on the leaf (2), between a locked position and an unlocked position... retaining means (12) designed capable of providing a force of resistance to the rotation of the latch (6)... elastic return means ensuring that it is held in the unlocked position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a movable stop (15) defined capable of being pushed back, from an active position (16) of unlocked maintenance of the latch (6), in an inactive unlocking position (17), to release the rotation of this latch (6), this under the impetus of a suitable control member (8)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP1878862B1Locking mechanism for a window sash
Publication Date: 2008.09.03 BUBENDORFF SA
  • EP1878862B1 patent drawingFigure 1~4
  • EP1878862B1 patent drawingFigure 5~7

AI summary

The device has a latch (6) mounted pivotedly on a shutter type leaf (2) between a locking position and an unlocking position in which the latch cooperates with a stop guard. The latch is controlled in rotation around its vertical pivoting axis under the impulsion of a control unit e.g. electric motor, for opening and closing the leaf. A movable stop (15) is pushed back from an active position into an inactive position for releasing the rotation of the latch under the impulsion of the stop guard when the leaf is in closing position. USE : Device for locking a shutter type leaf of a gate, door and window of a building and for maintaining the leaf in closed position. ADVANTAGE : The device permits to conveniently assure the locking of the shutter type leaf of a door when the leaf is in closing position. DESCRIPTION OF DRAWINGS : The drawing shows a perspective and schematic representation of locking device for leaf. 2 : Leaf 6 : Latch 11 : Front edge 15 : Movable stop 20 : Fixation support.