Window Sash Opening Limiter With Automatic Partial-Open Lock

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Solution Overview

Problem

Existing window and door assemblies lack a reliable and simple mechanism to limit the rotation to a defined, partially open position, risking accidental movement due to wind or improper operation.

Innovation Solution

A wing arrangement with a frame and a pivotable wing, featuring an opening limiting device comprising a switching rod, guide, and pivot arm, which allows defined pivoting to a partially open position and is locked automatically, using a self-locking device with a pivot bolt and locking element actuated by a handle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rotation limiting arrangement is provided on a window with a frame and sash, then the sash can be locked in a partially open position, but the device complexity increases with multiple components like rotatable locking elements and rotation limiters

Engineering Contradiction:
Improvereliability of rotation limitingVSAvoidcomplexity of locking mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The opening limiting device automatically locks the sash in the partially open position through the interaction between the pivot arm engaging the guide groove's closed end and the self-locking device. The system serves itself by using the sash's own position to trigger the locking action, eliminating the need for separate control mechanisms and reducing overall device complexity while maintaining reliability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention combines the opening limiting function and the self-locking function into a single integrated device. The pivot arm, guide groove, and self-locking device work together as one unified mechanism rather than separate components, reducing the number of parts and simplifying the overall structure while ensuring reliable limitation of rotation

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If multiple switches or additional mechanisms are added to control the opening position, then the opening control becomes more precise, but the ease of operation decreases requiring additional switches

Engineering Contradiction:
Improveprecision of opening position controlVSAvoidease of operation
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system automatically determines and locks at the correct opening position based on the sash's movement itself. The pivot arm naturally engages the closed end of the guide groove when the sash reaches the desired partially open position, triggering automatic locking without requiring the user to operate additional switches or controls, thus maintaining both precision and ease of operation

Inventive Principle:
Principle #25Self-service

3Device complexity

If a simple opening limiter design is used, then the device complexity is reduced, but the reliability decreases risking incorrect operation or accidental movement

Engineering Contradiction:
Improvesimplicity of designVSAvoidreliability of position locking
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The self-locking device automatically engages when the pivot arm reaches the closed end of the guide groove, using the sash's own movement to trigger the locking action. This self-actuating mechanism ensures reliable locking without complex control systems, as the locking is triggered automatically by the physical position of the sash itself

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The guide groove is designed with a closed end that provides a natural stopping point for the pivot arm. The curved or contoured end of the groove ensures that the pivot arm reliably engages at the correct position, providing inherent mechanical guidance that enhances reliability without adding complexity to the overall design

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Ease of operation

If the sash can pivot freely without limitation, then the ease of operation is maximized, but the risk of accidental closure or wind-induced movement increases

Engineering Contradiction:
Improvefreedom of movementVSAvoidwind-induced movement or accidental closure
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system allows the sash to move freely during normal operation but automatically locks itself when reaching the partially open position. The self-locking mechanism activates based on the sash's position, providing automatic protection against wind-induced movement or accidental closure without restricting the user's ability to open and close the sash normally

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The opening limiting device pre-establishes a defined stopping point (the closed end of the guide groove) before the sash can be fully opened. This preliminary limitation prevents the sash from reaching positions where it could be accidentally closed or damaged by wind, while still allowing full freedom of movement within the safe operating range

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP4174265B1Wing assembly
Publication Date: 2026.04.08 GRETSCH UNITAS GMBH BAUBESCHLAGFABRIK
  • EP4174265B1 patent drawingFigure 1
  • EP4174265B1 patent drawingFigure 2~3
  • EP4174265B1 patent drawingFigure 4a~4b

AI summary

The invention relates to a wing arrangement (10) comprising a frame (12) and a wing (14) of a door or window pivotably mounted on the frame (12), wherein an opening limiting device (40) is provided which allows the wing (14) to pivot relative to the frame (12) only to a partially open position, wherein the opening limiting device (40) comprises a switching rod (46), a guide device (48) and a pivot arm (44), wherein the guide device (48) has a guide groove (52) closed at one end, wherein in the partially open position of the wing the pivot arm engages with a pin (50) in the guide groove and rests against its closed end (76), wherein a self-locking device (42) is provided which is configured to automatically lock the pin in such a way that the pin is caught in the guide groove when it rests against the closed end of the guide groove.