Lever Transmission for Double-Leaf Windows

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Solution Overview

Problem

The existing forend lever mechanism for double-leaf windows and balcony doors faces difficulties in simple transport and conversion to a ready-to-operate state due to the bearing pin dragging over the connecting rod section, making it challenging to find the bore of the driving connection during initial actuation.

Innovation Solution

Incorporating a spring element with a bearing pin that creates a form fit between the operating lever, handlebar, or connecting rod section, allowing the actuating lever to pivot parallel for transport in an unlocked position and transitioning to a locked position after actuation, with the spring element being accessible for assembly and visual inspection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the bearing pin is separated from the driving connection before first actuation, then the forend lever mechanism can be mounted in the unlocked position with space-saving parallel transport, but the bearing pin drags over the connecting rod section and the bore of the driving connection can only be found with difficulty during initial actuation

Engineering Contradiction:
Improvetransport spaceVSAvoidinitial actuation ease
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The spring element is pre-loaded in the bearing pin before first actuation, creating a preliminary condition where the bearing pin is automatically guided toward the bore of the driving connection. This preliminary spring-loaded positioning action eliminates the difficulty of finding the bore during initial actuation while maintaining the space-saving parallel transport configuration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring element acts as an intermediary between the bearing pin and the driving connection bore. It provides a mechanical guidance mechanism that actively directs the bearing pin into the bore during initial actuation, resolving the problem of the bearing pin dragging over the connecting rod section without compromising the unlocked position mounting.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the actuating lever is pivoted parallel over the faceplate for transport, then space-saving transport is achieved, but the connection of the bearing pin to the adjacent section must be released and re-established during initial actuation

Engineering Contradiction:
Improvetransport spaceVSAvoidmounting complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The spring element enables the bearing pin to self-guide into the driving connection bore during initial actuation without requiring external assistance or complex alignment procedures. The spring's inherent mechanical property provides the self-service guidance function, reducing mounting complexity while maintaining space-saving transport capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring element changes the mechanical parameter of the bearing pin from a passive, drag-prone component to an actively guided component with spring-loaded positioning. This parameter change (adding elastic force) simplifies the initial actuation process while preserving the parallel transport configuration.

Inventive Principle:
Principle #35Parameter changes

3Ease of repair

If the spring element is positioned to be accessible for assembly and visual inspection, then ease of maintenance is improved, but it may interfere with the locked position operation when covered by the operating lever

Engineering Contradiction:
Improvespring element accessibilityVSAvoidlocked position operation
Core Design Contradiction:
Ease of repairVSEase of operation

Solution Approach 1:

The spring element is positioned with local quality differentiation: it is accessible for assembly and inspection in the transport/unlocked position, while being covered by the operating lever in the locked position. This localized accessibility arrangement satisfies maintenance requirements without interfering with operational function, as the spring only needs to be accessed during initial setup or maintenance, not during normal locked position operation.

Inventive Principle:
Principle #3Local quality

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

Enables easy transport in a space-saving manner and ensures the connecting rod can be moved between locking and unlocking positions by pivoting the operating lever, with the spring element's position visible and easily checked, enhancing the operational state of the forend lever mechanism.

Implementation Method 1

a spring element and that the spring element is designed after initial actuation to produce a form fit acting in the longitudinal direction between the bearing pin and an adjacent section

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3708743B1Lever transmission for selectively locking or unlocking an overlapped leaf of double-leaf windows
Publication Date: 2021.11.10 WINKHAUS
  • EP3708743B1 patent drawingFigure 1
  • EP3708743B1 patent drawingFigure 2~4
  • EP3708743B1 patent drawingFigure 5~8

AI summary

A lever mechanism (7) for driving a connecting rod section (13) has a bearing pin (20) which is latched to a sleeve rail section (11) by a spring element (18). The bearing pin (20) supports a link (12) of an actuating lever (10). In a transport position, the bearing pin (20) can be moved so that, in an unlocked position of the lever mechanism (7), the actuating lever (10) lies above the sleeve rail section (11). After initial actuation, the spring element (18) latches the bearing pin (20) in a position in which the lever mechanism (7) is ready for operation.