Toothed Ejection Lever for Slip-Free Furniture Drive Torque

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Solution Overview

Problem

Existing furniture drives with ejection levers experience inefficient power transmission due to non-positive contact, leading to slip and reduced efficiency when moving furniture parts, especially those with small protrusions or deep furniture bodies.

Innovation Solution

The ejection lever is equipped with toothing that allows for positive force transmission, featuring a non-circular design with adjustable sections to optimize torque distribution, enabling high initial torque for heavy loads and reducing noise through sound-absorbing coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If non-positive contact (sliding support) is used for power transmission, then the structure is simple, but power transmission efficiency is low due to slip

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The ejection lever is divided into two separate ejection lever parts (first and second parts) that can be adjusted relative to each other. The toothing is provided on one of these parts, creating a segmented structure that enables positive power transmission while maintaining adjustability for different application requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The toothing acts as an intermediary mechanism between the ejection lever and the furniture part. Instead of direct sliding contact, the toothing engages with corresponding features to transmit force positively, eliminating slip while the intermediate space allows for force transmission during ejection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If fixed length ejection lever is used, then manufacturing is simple, but adaptability to different furniture configurations is limited

Engineering Contradiction:
Improveadaptability to different furniture configurationsVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The ejection lever is designed with adjustable length through the relative movement of the first and second ejection lever parts. This dynamic adjustment capability allows the lever to be configured for different furniture types and drawer depths, transforming a static component into an adaptable one without requiring multiple fixed-length levers.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The length parameter of the ejection lever can be changed by adjusting the position of the ejection lever parts relative to each other. This parameter adjustment enables the same lever mechanism to work effectively with different furniture configurations, from shallow to deep drawers, without changing the overall device structure.

Inventive Principle:
Principle #35Parameter changes

3Power

If uniform toothing is used throughout, then manufacturing is simple, but torque optimization across different rotation angles is not achieved

Engineering Contradiction:
Improvetorque distributionVSAvoidtoothing manufacturing complexity
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The toothing is not uniformly distributed but is strategically positioned on specific sections of the ejection lever parts. This local concentration of toothing features allows for optimized torque transmission at critical rotation angles while reducing manufacturing complexity compared to complex non-circular gear designs. The toothing is provided at least in regions rather than uniformly throughout.

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

This solution provides slip-free, angularly accurate power transmission with high efficiency, effectively ejecting heavily loaded drawers from closed positions without issues, while minimizing noise and optimizing drive torque curves.

Implementation Method 1

the ejection surface of the ejection lever has a toothing at least in regions... positive force transmission can be made possible, with significantly higher forces being able to be transmitted compared to non-positive transmission. The form-fitting transmission enables slip-free, angularly accurate transmission of the rotational movement

Methodology Applied
Scientific EffectPositive force transmission through toothing engagement: Gear

Implementation Method 2

the toothing and/or the counter-toothing interacting with the toothing can be provided with a sound-absorbing coating, at least in some areas

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP3068964B1Arrangement with a furniture drive
Publication Date: 2019.03.13 JULIUS BLUM GMBH
  • EP3068964B1 patent drawingFigure 1
  • EP3068964B1 patent drawingFigure 2a~2b
  • EP3068964B1 patent drawingFigure 3

AI summary

The invention relates to a furniture drive (4) for ejecting a moveable furniture part (3) from a closed end position relative to the body of the item of furniture (2), comprising; a housing (9), an electric drive unit (10) which is arranged in or on the housing (9), an ejection lever (12) which can be driven by the electric drive unit (10) for transferring a movement to the moveable furniture part (3). The ejection lever (12) is mounted so that it can rotate about a rotational axis (11) on one side and comprises a free lever end (13) on the other side. Said ejection lever (12) comprises an ejection surface (14) between the rotational axis (11) and the free lever end (13). Said ejection surface (14) of the ejection lever (12) comprises, at least in sections, a toothing (15).