Coupled Drawer Latching Fittings for Two-Side Unlocking

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Solution Overview

Problem

Existing drawer locking systems for pull-out guides often require pressing the drawer into the furniture body to open, which can cause damage and lead to incorrect operation, especially with wide drawers where only one side of the locking mechanism may be unlocked.

Innovation Solution

A latching system with two coupled latching fittings, each with a switching cam and energy accumulator, allowing the drawer to be opened by either pushing or pulling, ensuring both sides are unlocked simultaneously to prevent incorrect operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the drawer is pressed into the furniture body to unlock the locking mechanism, then the drawer can be opened, but this can cause damage to the drawer or furniture

Engineering Contradiction:
Improvedrawer opening operationVSAvoiddamage to drawer or furniture
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional unlocking mechanism by enabling both pushing and pulling operations to unlock the drawer. The switching cam is designed with a loop-shaped section that allows the switching element to be disengaged from the latching depression either by pushing the drawer closed or by pulling the drawer open, eliminating the need to force the drawer against spring pressure and preventing damage.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If only one side of the locking mechanism is unlocked in wide drawers, then partial opening is possible, but handling becomes problematic and incorrect operations may occur

Engineering Contradiction:
Improvelocking mechanism performance in wide drawersVSAvoidhandling of drawer
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent couples multiple latching fittings together through a common switching mechanism. When one switching element is disengaged from its latching depression, the coupling mechanism ensures that other switching elements are simultaneously disengaged from their respective latching depressions. This merging of the unlocking actions across multiple sides ensures coordinated operation and prevents incorrect handling.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the force of energy storage devices is increased to ensure reliable locking, then unlocking reliability improves, but unintentional opening may occur

Engineering Contradiction:
Improvelocking reliabilityVSAvoidunintentional opening
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs dynamic force balancing through the switching cam mechanism. The loop-shaped switching cam allows the switching element to follow a controlled path during engagement and disengagement. The energy storage devices are preloaded to provide reliable locking forces, but the geometric design of the switching cam ensures that these forces are directed appropriately during normal operation and do not cause unintentional opening.

Inventive Principle:
Principle #15Dynamics

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 system simplifies operation by allowing choice in opening method and prevents incorrect unlocking, ensuring the drawer opens even if only one side is initially unlocked, while also preventing unintentional opening through adjustable forces.

Implementation Method 1

a latching depression for the switching element preloaded by an energy accumulator being formed on a loop-shaped section of the switching cam

Methodology Applied
Scientific EffectEnergy storage device (spring): Spring

Data Source

PatentEP2294944B1Locking system
Publication Date: 2015.08.26 PAUL HETTICH GMBH & CO KG
  • EP2294944B1 patent drawingFigure 1~2
  • EP2294944B1 patent drawingFigure 3
  • EP2294944B1 patent drawingFigure 4A~4C

AI summary

The locking system has two locking fittings (50), which are coupled with each other by a movable furniture piece. Each locking fitting has a switching curve, in which a switching element is guided. A locking cavity is formed for the switching element at a loop shaped section.