Ejection device for a movable furniture part

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Solution Overview

Problem

Existing ejection devices for movable furniture parts often have a large overpressure path, leading to undesirable triggering or unlocking due to vibrations, and lack efficient mechanisms for secure locking and easy unlocking.

Innovation Solution

An ejection device with a locking mechanism where the line of action of the ejection force accumulator runs through the axis of rotation, creating a 'dead center' locking position, and can be unlocked by overpressing the movable furniture part, causing the axis and line of action to separate, allowing the ejection element to rotate and eject the part via a clamping element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the line of action of the ejection force accumulator does not run through the axis of rotation, then the ejection element can rotate easily to eject the movable furniture part, but the locking position becomes unstable and susceptible to unwanted triggering by vibrations

Engineering Contradiction:
Improveease of ejecting movable furniture partVSAvoidstability of locking position
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The ejection force accumulator is pre-loaded during the closing movement to store sufficient energy. When the movable furniture part is in the closed position, the accumulator is already charged with force, so that upon triggering, the stored energy immediately drives the ejection element to rotate and eject the part without requiring additional force during the ejection act itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The design creates a dead center locking position where the line of action of the ejection force accumulator runs through the axis of rotation of the ejection element. This configuration creates a stable equilibrium state (like a pendulum at its lowest point) where small disturbances such as vibrations cannot cause spontaneous rotation, as the system is in a potential energy minimum.

Inventive Principle:
Principle #12Equipotentiality

2Force

If a large overpressure path is used, then the ejection element can overcome friction and inertia more easily, but the locking position becomes less stable and more prone to unwanted triggering

Engineering Contradiction:
Improveforce for overcoming friction and inertiaVSAvoidstability of locking position
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The ejection force accumulator accumulates the necessary force during the closing movement, so that the full ejection force is available immediately when needed, rather than requiring a large overpressure path to build up force gradually.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By creating a dead center locking position, the system achieves stable locking with minimal overpressure path. The stable equilibrium ensures that small forces from vibrations cannot overcome the locking, while the pre-loaded accumulator ensures sufficient force is available for intentional ejection.

Inventive Principle:
Principle #12Equipotentiality

3Productivity

If the line of action and axis of rotation are separated, then the ejection element rotates to eject the part, but additional force and movement are required that could cause unwanted triggering

Engineering Contradiction:
Improvespeed of ejectionVSAvoidresistance to unwanted triggering
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The triggering action (pressing the movable furniture part into the overpressing position) is performed in advance to separate the line of action from the axis of rotation and initiate rotation. The ejection force accumulator is also pre-loaded during closing, so that once triggered, the ejection occurs rapidly using stored energy rather than requiring continuous force application.

Inventive Principle:
Principle #10Preliminary action

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 design provides secure locking with minimal force or movement required for unlocking, preventing unwanted triggering and ensuring reliable operation by using friction and inertia to stabilize the locking position.

Implementation Method 1

an ejection force accumulator (5) which acts on the ejection element (4)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Undesirable triggering or unlocking of this locking device due to vibrations is achieved by appropriately adjusted friction and inertia between the components involved

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

Undesirable triggering or unlocking of this locking device due to vibrations is achieved by appropriately adjusted friction and inertia between the components involved

Methodology Applied
Scientific EffectInertia: Inertia

Data Source

PatentEP3307111B1Ejection device for a movable furniture part
Publication Date: 2022.08.17 JULIUS BLUM GMBH
  • EP3307111B1 patent drawingFigure 1
  • EP3307111B1 patent drawingFigure 2~3
  • EP3307111B1 patent drawingFigure 4~5

AI summary

The invention relates to an ejection device (1) for a movable furniture part (2), comprising an ejection element (4) that can rotate about a rotational axis (X) and ejects the movable furniture part (2) from a closed position (SS) into an open position (OS), an ejection force storage element (5) which applies a force to the ejection element (4), and a locking device (17) for locking the ejection element (4) in a locking position (VS), the line of application (W) of the ejection force storage element (5) running through the axis of rotation (X) when in said locking position (VS).