Window Security Fitting Locking Scissor Arm

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Solution Overview

Problem

Existing window and door opening restrictors with child safety features, such as scissor arms, are prone to incorrect handling and manipulation, leading to mechanical stress and potential breakage, especially during cleaning or intentional tampering, which can result in the sash becoming stuck open.

Innovation Solution

A security fitting with a base body and stop means is provided for the rebate groove of a window or door frame, featuring a securing mechanism that locks the scissor arm in place, preventing it from being swiveled out and ensuring it remains engaged with the sash fitting, thus preventing unintended manipulation and ensuring secure operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the scissor arm is made easily manipulable for cleaning purposes, then ease of operation is improved, but reliability deteriorates due to intentional tampering and unintentional misplacement

Engineering Contradiction:
Improveease of manipulationVSAvoidsecurity against tampering
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The scissor arm is designed with differentiated zones: an engagement region that interfaces with the sash fitting and a distinct locking region that interfaces with the safety means. This local differentiation allows the arm to be easily engaged and disengaged for cleaning purposes while simultaneously providing a secure locking mechanism that prevents intentional tampering and unintentional misplacement.

Inventive Principle:
Principle #3Local quality

2Reliability

If the scissor arm is secured rigidly in the release position, then reliability is improved, but ease of operation deteriorates as the arm cannot be manipulated for cleaning

Engineering Contradiction:
Improvesecurity of scissor armVSAvoidmanipulability for cleaning
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism employs a dynamic design where the safety means can transition between locked and unlocked states. During normal operation and cleaning, the scissor arm remains freely manipulable. When security is required, the safety means engages with the locking geometry on the scissor arm to prevent further manipulation, thus providing reliability only when needed without compromising ease of operation.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the opening limiter is designed with simple holding function, then device complexity is reduced, but reliability deteriorates due to lack of protection against incorrect handling

Engineering Contradiction:
Improvesimplicity of opening limiterVSAvoidprotection against incorrect handling
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The safety means acts as an intermediary component between the frame and the scissor arm. This additional element provides the necessary security function without fundamentally redesigning the scissor arm or opening limiter mechanism. The safety means includes a locking geometry that engages with a corresponding feature on the scissor arm, creating a passive mechanical lock that prevents incorrect handling while maintaining the overall simplicity of the device.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3702562B1Fitting; locking fitting and frame and wing arrangement
Publication Date: 2021.09.22 WILH SCHLECHTENDAHL & SOEHNE GMBH & CO KG
  • EP3702562B1 patent drawingFigure 1A
  • EP3702562B1 patent drawingFigure 1B~1C
  • EP3702562B1 patent drawingFigure 2

AI summary

The invention relates to a safety fitting part provided for arrangement in or on a rebate groove (9) of a frame (3) of a window or door, comprising a base body (10) and a stop element (11) provided for the base body (10) for fastening in the rebate groove (9), wherein a safety element (12) for securing and/or locking a scissor arm (2) mounted on the frame (3), preferably in a release position of a sash (5) of the window or door, is provided on the base body (9), wherein an elongated guide (13) for the stop element (11) is provided on the base body (10), and wherein the base body (10) is displaceable relative to the stop element (11) along the guide (13).