Drawer Ejection Mechanism With Pawl Unlocking Under Load

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Solution Overview

Problem

Existing ejection mechanisms for movable furniture parts are unstable and require delicate components that can only absorb limited mechanical loads, making them prone to damage and difficult to unlock easily.

Innovation Solution

An ejection mechanism with a pawl that can be coupled to a driver, allowing for tensioning before reaching a closed position, and a self-closing mechanism that uses a spring-loaded activator to easily unlock and lock the driver, utilizing a combination of pivot points, cam guides, and elastic components for stable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking mechanism with a driver and cam guide is used to hold furniture parts in closed position, then the furniture parts can be securely locked, but the mechanism becomes unstable and prone to damage under mechanical loads

Engineering Contradiction:
Improvestability of locking mechanismVSAvoidmechanical load capacity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The locking mechanism is divided into functionally independent components: the driver (11) for locking/unlocking operations, the activator (5) for triggering, and the pawl (80, 81) for controlled movement. This segmentation allows each component to be optimized for its specific function, improving overall reliability and load capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pawl (80, 81) is positioned in advance at a distance from the activator (5) along the curved guide (7). This preliminary positioning enables the pawl to engage the driver (11) before the closed position is reached, allowing tensioning to occur in advance and preventing sudden load shocks that could damage the mechanism.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the driver is locked on the curved guide to hold closed position, then secure locking is achieved, but unlocking becomes difficult and requires pressing the drawer

Engineering Contradiction:
Improvelocking securityVSAvoidease of unlocking
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The pawl (80, 81) acts as an intermediary between the activator (5) and the driver (11). It transmits the unlocking force in a controlled manner, allowing the driver to be released from the locked position on the curved guide (7) without requiring direct pressing of the drawer, thereby easing operation while maintaining locking security.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pawl (80, 81) is spring-loaded and automatically engages and disengages the driver (11) based on the position of the activator (5). This self-service mechanism eliminates the need for manual intervention to unlock, as the system automatically performs the unlocking action when the activator moves to the appropriate position.

Inventive Principle:
Principle #25Self-service

3Device complexity

If delicate components are used in the locking mechanism, then the structure can be compact, but the components can only absorb limited mechanical loads and are prone to damage

Engineering Contradiction:
Improvestructural compactnessVSAvoidmechanical load absorption
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The pawl (80, 81) is designed with spring loading, changing its mechanical parameters to provide both compactness and high load capacity. The spring mechanism allows the pawl to be compact in structure while absorbing significant mechanical loads through elastic deformation, resolving the contradiction between compactness and strength.

Inventive Principle:
Principle #35Parameter changes

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 mechanism provides a stable and easy-to-use solution for unlocking and locking movable furniture parts, preventing damage and ensuring reliable operation even under varying installation conditions.

Implementation Method 1

The counterforce for moving the movable part back can be applied by spring force, by elastic deformation, in particular of subcomponents

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

In order to drive over the driver of the ejection device, the pawl can be pivoted perpendicularly to the opening direction via a pivot point

Methodology Applied
Scientific EffectRotational movement:

Implementation Method 3

the activator or pawl can be reset to the home position by gravity or by spring loading

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2465381B1Ejection mechanism
Publication Date: 2019.04.03 PAUL HETTICH GMBH & CO KG
  • EP2465381B1 patent drawingFigure 1
  • EP2465381B1 patent drawingFigure 2A~2B
  • EP2465381B1 patent drawingFigure 3A~3B

AI summary

The mechanism has an activator (5) coupled to a driver in a locked position and moved relative to a curve guide (7). The driver is prestressed in direction by a force accumulator (8). The driver is released by movement of the activator relative to the curve guide or by movement of another curve guide relative to another activator in the locked position. The former activator and/or the curve guide are moved in the direction and an opposite direction to release the driver. The mechanism is installed at a pull-out guide (1). Independent claims are also included for the following: (1) a pull-out guide for a drawer, comprising an ejection mechanism (2) an ejection system comprising ejection mechanisms.