Espagnolette Locking Lever for Tilt-and-Turn Window Security

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Solution Overview

Problem

Existing window and door locking systems, such as espagnolette fittings, lack a simple, resilient, and secure design that can be retrofitted independently, particularly for tilt-and-turn sashes, and often require manual activation or have vulnerabilities in their construction.

Innovation Solution

A locking device with a pivotally attached locking lever that prevents the locking bolt from exiting the locking pocket in one position and releases it in another, allowing for automatic engagement and disengagement based on the espagnolette fitting's position, enhancing security and ease of operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a spring element is used to automatically lock the locking bolt in the strike plate pocket, then the locking mechanism achieves automatic engagement, but the design only provides for one turning opening and one locking position, making it incompatible with tilt-and-turn sashes

Engineering Contradiction:
Improveautomatic locking engagementVSAvoidcompatibility with tilt-and-turn sashes
Core Design Contradiction:
Extent of automationVSAdaptability or versatility

Solution Approach 1:

The locking lever is designed to pivot between multiple positions (first position for preventing bolt exit, second position for releasing the pocket) based on the drive rod fitting's position. This dynamic adjustment allows the same mechanism to accommodate both locked and tilt-open positions, enabling compatibility with tilt-and-turn sashes while maintaining automatic engagement through the spring element's force

Inventive Principle:
Principle #15Dynamics

2Reliability

If hook levers with claw thumbs are used to grip the bolt shank, then security is slightly improved, but the design requires many small individual parts and does not prevent force being applied to the drive rod fitting

Engineering Contradiction:
Improvesecurity against break-inVSAvoidnumber of small individual parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking lever combines multiple functions into a single component: it acts as a stop to prevent bolt exit, provides a gripping surface with the locking edge, and works with the spring element to maintain constant force. This integration eliminates the need for multiple separate hook levers and claw thumbs, reducing part count while maintaining security against break-in attempts

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If a slide is used to move along the bolt pin's movement and close entry/exit openings, then the locking position can be engaged, but the locking bolt always forces the slide into its release position, providing no added safety

Engineering Contradiction:
Improvelocking position engagementVSAvoidsecurity against forced opening
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The locking lever is positioned to prevent the locking bolt from exiting the locking pocket in the first place, before any forced opening attempt can occur. By maintaining constant contact and applying preventive force through the spring element, the system stops potential intrusion at the earliest stage, making subsequent slide mechanisms unnecessary for security

Inventive Principle:
Principle #9Preliminary anti-action

4Reliability

If a backstop with coupling components and spring locks is used on push rod sections, then security against break-in is improved, but the design is intricate and requires precise fitting of six components

Engineering Contradiction:
Improvesecurity against break-inVSAvoidnumber of components and precision requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking lever integrates the backstop function, coupling interface, and spring lock mechanism into a single pivoting component. This eliminates the need for separate coupling components and spring locks on multiple push rod sections, reducing the system from six precisely-fitted parts to one robust component that maintains security while simplifying installation and reducing precision requirements

Inventive Principle:
Principle #5Merging (Combining)

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 a secure and resilient locking mechanism that can be easily retrofitted, automatically engaging or disengaging to prevent unauthorized opening while allowing supervised operation, enhancing safety and usability.

Implementation Method 1

a locking lever (11) which is pivotally attached to the frame (2) on a pivot axis perpendicular to the fold (9) and which points with a free end (13) towards the locking pocket (20)

Methodology Applied
Scientific EffectPivot motion: Hinge

Implementation Method 2

The locking lever (11) can be pivoted by the locking bolt (8) and can abut with its free end (13) against the locking pocket (20) of the strike plate (3)

Methodology Applied
Scientific EffectMechanical leverage: Lever

Data Source

PatentEP3759298B1Window or door
Publication Date: 2024.09.04 SIEGENIA AUBI KG
  • EP3759298B1 patent drawingFigure 1
  • EP3759298B1 patent drawingFigure 2
  • EP3759298B1 patent drawingFigure 3

AI summary

The invention relates to a window or a door, comprising an espagnolette fitting (1), by means of which a locking bolt (8) can be moved along a locking pocket (20), which is open in the longitudinal direction of the fold (9), of a locking plate (3) fixed to the fold (9), wherein at least one locking member is provided in order to prevent the espagnolette (6) from being pushed back on one of the locking pins in the opening direction. The aim of the invention is to simplify the construction of the blocking device (4) and to allow a reliable and resilient design, which can be retrofitted independently of the fitting type. This aim is achieved, according to the invention, in that the blocking device (4) comprises a locking lever (11), which is attached to the fold (9), and which with a free end (11) points toward the locking pocket (20), and which in a first position prevents the locking bolt (8) from exiting the locking pocket (20), and in a second position releases the locking pocket (20).