Pull-Out Guide Locking Mechanism for Reliable Sequence Control

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Solution Overview

Problem

Existing pull-out guides for household appliances and furniture lack defined sequence control and functional reliability, particularly in locking and unlocking mechanisms, leading to imprecise latching forces and disruptive movement sequences.

Innovation Solution

A pull-out guide with a resiliently prestressed locking mechanism, featuring a blocking element that can be fixed to one of the rails and an unlocking element on the third rail, allowing for precise control and reliable operation by overcoming locking forces, with a compact design using few components and materials suitable for high-temperature applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two latching means are provided in a full extension with at least three rails, then the running rail can be locked in one or more positions, but the latching forces can only be determined imprecisely and sequence control cannot be implemented

Engineering Contradiction:
Improvelocking reliabilityVSAvoidlatching force precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The locking mechanism is segmented into distinct functional components: a locking element with a blocking section for positive locking, and a separate latching element for securing the rail in position. This segmentation allows independent optimization of locking force (through the blocking mechanism) and latching force precision (through the latching element's engagement with the rail profile), resolving the contradiction between reliable locking and precise force determination.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If locking in an intermediate position is provided, then the rail can be secured at intermediate positions, but the locking must be canceled when the running rail is retracted or extended, which is perceived as disruptive

Engineering Contradiction:
Improveintermediate position lockingVSAvoidcontinuous movement
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The locking mechanism is designed to be dynamically controllable through the unlocking element. The blocking section can be selectively engaged or disengaged based on the desired operation mode. When continuous movement is required, the blocking element is disengaged to allow smooth retraction and extension. When intermediate positioning is needed, the blocking element engages to secure the rail. This dynamic control resolves the contradiction between intermediate position locking and continuous movement.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a locking mechanism with resilient prestressing is used, then defined sequence control and high functional reliability are achieved, but the device complexity increases

Engineering Contradiction:
Improvefunctional reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking element is resiliently prestressed to automatically engage the blocking section with the rail profile without requiring external actuation. The spring force ensures positive locking is maintained throughout the operational range. This self-service mechanism achieves high functional reliability while minimizing the need for additional complex control systems, as the locking action occurs automatically based on the rail's position and the prestressing force.

Inventive Principle:
Principle #25Self-service

4Reliability

If an unlocking element is provided on the third rail, then incorrect operation is prevented and reliable unlocking with minimal force is achieved, but the device complexity increases

Engineering Contradiction:
Improveoperation reliabilityVSAvoidunlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The unlocking element acts as an intermediary between the user's input force and the blocking section. It is positioned on the third rail and transmits the unlocking force to the locking element, causing the blocking section to disengage from the rail profile. This intermediary mechanism prevents incorrect operation by requiring the proper sequence of actions, while the mechanical leverage provided by the unlocking element's geometry allows reliable unlocking with minimal user force, avoiding the need for complex motorized or electronically controlled systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution provides a defined sequence control and high functional reliability during prolonged use, ensuring smooth and reliable movement with minimal user effort, suitable for various applications including ovens, furniture, and medical environments.

Implementation Method 1

a blocking element (74) which can be resiliently prestressed into the locking position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

an unlocking element (75) to unlock the locking mechanism and allow movement of the first rail (2) to the second rail (3)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3153067B1Pull-out guide
Publication Date: 2019.07.31 PAUL HETTICH GMBH & CO KG
  • EP3153067B1 patent drawingFigure 1~2
  • EP3153067B1 patent drawingFigure 3~4
  • EP3153067B1 patent drawingFigure 5~6

AI summary

A pull-out guide (1, 1', 1"), in particular for household appliances or furniture, comprises at least three rails (2, 3, 4) which are mounted such that they can be moved relative to one another, one rail (2) being able to be fixed to a body and a rail (4 ) can be connected to a pusher element A locking mechanism (40, 50, 70, 70') is provided in order to lock a first rail (2) relative to a second rail (3) against movement in a predetermined position, the The blocking mechanism (40, 50, 70, 70') comprises a blocking element (42, 52, 74) which is spring-biased into the blocking position.