Multi-Position Pull-Out Rail Locking Against Slippage

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Solution Overview

Problem

Existing pull-out guides for household appliances often fail to securely engage due to slippage between rails during jerky movements, leading to incomplete locking and potential accidental release.

Innovation Solution

A pull-out guide with a locking mechanism featuring multiple adjacent locking positions, allowing for compensation of slippage and ensuring secure locking in either of two positions, along with a metallic construction for heat resistance and a mechanically reliable design with a movable locking element and integral unlocking mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking mechanism is provided to control the movement of rails, then sequence control is improved, but slippage during jerky movements causes the locking mechanism to fail to engage

Engineering Contradiction:
Improvelocking engagement reliabilityVSAvoidsensitivity to jerky movements
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism is divided into multiple locking positions (first locking position and second locking position) along the rail. This segmentation allows the locking element to engage at different locations, providing backup engagement points that compensate for slippage during jerky movements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking mechanism is designed with multiple predetermined locking positions before the final extended position. These positions act as cushioning points that can engage if slippage occurs during extension, preventing complete failure of the locking mechanism.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If multiple locking positions are provided to compensate for slippage, then locking reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvelocking position securityVSAvoidnumber of locking positions
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism uses a segmented approach with multiple locking positions arranged linearly along the rail. Each position consists of simple geometric features (protrusions and receptacles) rather than complex mechanisms, achieving reliability through redundancy rather than complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking mechanism changes the positional parameter of engagement points along the rail. By providing multiple locking positions at different locations (e.g., 3-15mm apart), the system compensates for slippage without requiring complex additional components.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If the locking mechanism and latching mechanism are made of metallic components, then heat resistance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveheat resistanceVSAvoidmetallic component fabrication
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The material parameter is changed to metallic components with appropriate heat-resistant properties. The locking and latching mechanisms are fabricated from metals that can withstand high temperatures, such as in oven applications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The solution uses metallic materials that combine mechanical strength with heat resistance. The metallic components are designed to maintain their mechanical properties across a wide temperature range, suitable for household appliances like ovens.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3203876B1Pull-out guide
Publication Date: 2018.09.05 PAUL HETTICH GMBH & CO KG
  • EP3203876B1 patent drawingFigure 1
  • EP3203876B1 patent drawingFigure 2~3

AI summary

A pull-out guide for household appliances or furniture comprises at least three rails (2, 3, 4) mounted for displacement relative to each other, wherein a first rail (2) can be fixed in a stationary manner to a body, at least one second rail (3) is provided between the first and a third rail (4), and the third rail (4) can be connected to a push element and can be displaced between a closed position and a pull-out position, wherein a latching mechanism (5) is provided in order to fix two rails (3, 4) in a detachable manner to each other by a latching, and a locking mechanism (6) is provided in order to lock two rails (2, 3) to each other in the pull-out position, wherein the locking mechanism (6) can be detached via an unlocking (7) provided on the additional rail (4), wherein the locking mechanism (6) has at least two adjacently arranged locking positions in order to lock the two rails (2, 3) in different locking positions. In this way, a reliable process control is achieved.