Concealed Window Fitting Multi-Joint Mechanism for 180 Swivel

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Solution Overview

Problem

Concealed window and door fittings typically allow only a limited swivel angle of up to 90° or 110° due to mechanical constraints, preventing full opening and compromising load-bearing capacity, especially for larger sashes.

Innovation Solution

A fitting with a multi-joint system involving a control lever and angular connecting tab, articulated to a wing corner bearing connecting piece, allowing the sash to pivot up to 180° by maintaining or increasing the distance between the sash pivot bearing and the frame, thus enabling greater swivel angles without reducing the load-bearing capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If concealed fittings are used to achieve aesthetic appearance, then the fittings are not externally visible when the sash is closed, but the maximum swivel angle is limited to 90° or 110°

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidswivel angle
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The opening control device is divided into multiple articulated segments including a control lever, connecting tab, and wing corner bearing connecting piece. These segmented components work together through articulated connections to enable the sash to swivel beyond 90° up to 180° while maintaining concealed aesthetic appearance when closed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fitting employs dynamic articulated connections between the control lever, connecting tab, and wing corner bearing connecting piece. This dynamic mechanism allows the sash to achieve variable swivel angles from 90° up to 180°, transforming the static limitation of concealed fittings into a dynamic range of motion.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the sash is swung open beyond 90° to achieve complete view, then the overlap with frame increases, but the load-bearing capacity may be compromised

Engineering Contradiction:
Improveswivel angleVSAvoidload-bearing capacity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The multi-joint mechanism performs preliminary geometric transformation by articulating the control lever and connecting tab before the sash reaches extreme positions. This preliminary action maintains optimal force distribution and bearing engagement throughout the opening sequence, preserving load-bearing capacity even at 180° opening angles.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The wing corner bearing connecting piece acts as an intermediary component between the sash support arm and the bearing band. It mediates the transmission of forces during large-angle opening, distributing loads through the articulated connections and maintaining structural integrity throughout the motion range.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2708692B1Fitting for concealed mounting in the rabbet between a wing and a frame of a window, a door or the like
Publication Date: 2018.03.21 WILH SCHLECHTENDAHL & SOEHNE GMBH & CO KG
  • EP2708692B1 patent drawingFigure 1
  • EP2708692B1 patent drawingFigure 2~3
  • EP2708692B1 patent drawingFigure 4

AI summary

The fitting (1) has a wing support arm (8) articulated at a bearing tape (7) and a wind corner bearing (5) fastened at a wing side and to a wing swivel bearing (6). An issuing device (10) is coupled with the bearing tape and the wing support arm. A wing pivots relative to the bearing tape by the wing swivel bearing, where the fitting is designed such that pivoting angle formed between the bearing tape and the wing support arm remains unchanged with the wing pivoting about 90-135 degrees.