Window Drive Device Rigid Chain Lever Mechanism

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Solution Overview

Problem

Existing drive devices for window or door sashes struggle with precise positioning and stability under wind loads, leading to mechanical stress and potential chain misalignment.

Innovation Solution

A drive device featuring a rigid chain with a single axis of rotation and a pivoted lever that extends parallel to the chain, allowing precise positioning and absorption of compressive forces, while preventing chain buckling and misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible chain with multiple degrees of freedom is used, then the chain can accommodate movement and positioning adjustments, but the sash cannot be held in a precise open position and excessive movement occurs under wind loads

Engineering Contradiction:
Improvechain flexibilityVSAvoidsash positioning precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The chain's degrees of freedom are reduced by constraining its movement to a single rotational axis at the lever connection point. This parameter change transforms the chain from a highly flexible component to one with controlled flexibility, maintaining enough adaptability to accommodate sash movement while preventing excessive movement that would compromise positioning precision under wind loads.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a chain with multiple degrees of freedom is used, then the chain can absorb movement variations, but the connecting parts experience mechanical stress and potential misalignment

Engineering Contradiction:
Improvechain movement stabilityVSAvoidconnecting parts strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The connection geometry between the chain and lever is optimized to align the chain's force transmission path with the lever's rotational axis. This parameter optimization ensures that forces are transmitted efficiently through the connecting parts without creating bending moments or misalignment stresses, thereby reducing mechanical stress on connecting components.

Inventive Principle:
Principle #35Parameter changes

3Force

If the chain is allowed to buckle, then the chain can accommodate compressive forces, but the sash positioning becomes imprecise and the chain hits frame corners

Engineering Contradiction:
Improvecompressive force absorptionVSAvoidsash positioning precision
Core Design Contradiction:
ForceVSMeasurement precision

Solution Approach 1:

The chain is segmented into discrete links that can articulate relative to each other, allowing the chain to accommodate compressive forces through controlled link articulation rather than buckling. This segmentation enables the chain to maintain its linear configuration while absorbing compressive loads, preventing both buckling-induced positioning errors and contact with frame corners.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If a complex lever mechanism with multiple rotation points is used, then the chain can be routed to avoid frame corners, but the device complexity increases

Engineering Contradiction:
Improvechain hitting frame cornersVSAvoidlever mechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The lever mechanism is extracted and simplified to its essential function: a single rotational connection between the chain and the sash assembly. By removing unnecessary intermediate rotation points and simplifying the lever geometry, the mechanism achieves adequate clearance from frame corners while significantly reducing overall device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

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 ensures the sash can be held in an open position with precise positioning and securely closed under wind loads, minimizing movement and mechanical stress, while maintaining thermal insulation.

Implementation Method 1

both tensile forces and compressive forces between the frame and casement can be transmitted via the chain

Methodology Applied
Scientific EffectForce transmission: Force

Implementation Method 2

the lever is mounted on the casement or the window frame so that it can rotate about only a single axis of rotation

Methodology Applied
Scientific EffectRotational motion: Hinge

Implementation Method 3

A 'rigid' chain can be bent at the individual chain links via a pinion of the drive

Methodology Applied
Scientific EffectMechanical deformation: Deformation

Data Source

PatentEP2743437B1Drive device to operate the leaf of a door or window
Publication Date: 2020.04.22 SCHUECO INTERNATIONAL KG
  • EP2743437B1 patent drawingFigure 1
  • EP2743437B1 patent drawingFigure 2~3
  • EP2743437B1 patent drawingFigure 4

AI summary

The device (1) has an electric motor drive (3) that is concealed in a rebate space between a window frame (2) and a wing frame and is arranged in a closed position of a wing. The drive comprises a rigid chain (4) which is movable on a side through a pinion gear and is fixed to an opposite side on a lever (5). The lever is extended parallel to the chain. The chain transmits both tensile forces and compressive forces between the window frame and the wing frame. The lever is rotatably mounted about an axis on the wing frame or the window frame.