Drawer Locking Fitting With Switching Cams for Directional Guidance

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Solution Overview

Problem

Existing drawer locking fittings can experience incorrect actuation when the shifting element moves in an unintended direction, particularly at junctions where it is not positively guided.

Innovation Solution

A detent fitting with at least two switching cams arranged on the switching curve, allowing the switching element to pass through in a predetermined direction while blocking movement in the opposite direction, and featuring chamfered edges and resilient spring elements for secure guidance and feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring-loaded switching element is used in a drawer guide locking mechanism, then the drawer can be locked in a closed position and opened by pushing in, but incorrect actuation can occur when the switching element moves in an unintended direction at junctions where it is not positively guided

Engineering Contradiction:
Improvelocking mechanism reliabilityVSAvoidswitching element guidance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The switching curve is divided into multiple segments by introducing at least two switching cams, each responsible for a specific portion of the switching element's path. This segmentation ensures that each cam can positively guide the switching element in its designated region, preventing incorrect actuation while maintaining the overall locking function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Switching cams are introduced as intermediary elements between the switching element and the switching curve. These cams act as mediators that provide positive guidance to the switching element at critical junctions, ensuring it moves only in the intended direction and preventing erroneous actuation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If switching cams are added to the switching curve to prevent incorrect actuation, then the switching element is reliably guided in the predetermined direction, but the device complexity increases

Engineering Contradiction:
Improveswitching element direction controlVSAvoidlocking fitting structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The switching cams are merged with the existing switching curve structure, integrating the guidance function into the cam profile itself rather than adding separate guiding mechanisms. This combining approach maintains reliability while minimizing the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The switching cams serve multiple functions: they guide the switching element in the predetermined direction, prevent incorrect actuation, and work in conjunction with the spring-loaded mechanism to enable both locking and unlocking operations. This multi-functionality reduces the need for additional separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Ensures the switching element can only be moved in the predetermined direction, preventing incorrect actuation and providing reliable operation with enhanced user feedback.

Implementation Method 1

a spring-loaded switching element

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Gas pressure springs, compression springs or rubber-elastic elements, for example, can be used to store energy for ejecting the push element.

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2292119B1Locking device and pull-out design
Publication Date: 2015.08.26 PAUL HETTICH GMBH & CO KG
  • EP2292119B1 patent drawingFigure 1
  • EP2292119B1 patent drawingFigure 2
  • EP2292119B1 patent drawingFigure 3

AI summary

The fitting has a switching element (9) movable along a switching curve (18), where the switching element is lockable at the switching curve in a closed position and is prestressed in a locked position by an energy accumulator (13). Switch cams (16, 17) are arranged at the switching curve for releasing the switching element in a predetermined flow direction and blocking the switching element opposite to the flow direction. Each of the cams has a bevel provided at a side edge, where one of the cams is arranged at an external side of a forward curve of the switching curve. An independent claim is also included for a pull-out guide comprising a guide rail connected with a catch fitting.