Pull-out guide for drawers

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Solution Overview

Problem

Existing pull-out guides for drawers face challenges in maintaining synchronization and stability during over-extension, as the drawer and body rails tend to move apart, leading to potential disengagement of the gearwheel and loss of synchronization, which complicates the over-extension mechanism.

Innovation Solution

The implementation of toothed rack end sections that protrude beyond the rolling element carriages and mesh with the gearwheel, along with supports on the cabinet and drawer rails to prevent separation and ensure synchronization, includes a beveled side for stable engagement and radial flanks to prevent lateral breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the drawer rail is extended beyond the body rail for over-extension, then the extension length is improved, but the synchronization between rails deteriorates due to loading deformation and gearwheel disengagement

Engineering Contradiction:
Improveextension lengthVSAvoidsynchronization
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The toothed rack end sections are designed to protrude beyond the rolling element carriages in advance, so that when over-extension occurs, these pre-positioned end sections automatically engage with the gearwheel to maintain synchronization without requiring additional complex mechanisms

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The toothed rack end sections act as intermediary elements between the rolling element carriages and the gearwheel. These end sections provide a direct mechanical connection that ensures the gearwheel remains engaged even when the main toothed racks separate due to loading deformation, thus maintaining synchronization during over-extension

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If the toothed racks are allowed to move apart in the overextension range, then the over-extension capability is improved, but the gearwheel disengages and synchronization is lost

Engineering Contradiction:
Improveover-extension capabilityVSAvoidsynchronization maintenance mechanism
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The toothed rack is segmented into a main body portion and a protruding end section. The end section is designed to remain engaged with the gearwheel while the main body can separate during over-extension, allowing the system to achieve extended range of motion without losing synchronization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The toothed rack end sections automatically perform the function of maintaining gearwheel engagement without requiring external control mechanisms. When over-extension occurs, the geometry of the end sections and their engagement with the gearwheel naturally maintains synchronization, eliminating the need for complex additional synchronization devices

Inventive Principle:
Principle #25Self-service

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

This solution effectively maintains synchronization and stability during over-extension by preventing the toothed racks from moving apart and ensuring continuous engagement with the gearwheel, thereby enhancing the reliability and functionality of the pull-out guide.

Implementation Method 1

a center rail running differentially between the two, which is guided in two rolling element carriages

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

the center rail has a gear wheel and the two rolling element carriages each have a toothed rack meshing with the gear wheel

Methodology Applied
Scientific EffectGear mechanism: Gear

Data Source

PatentEP2590533B1Pull-out guide for drawers
Publication Date: 2017.08.02 ANTON SCHNEIDER GMBH
  • EP2590533B1 patent drawingFigure 1~2a
  • EP2590533B1 patent drawingFigure 2b~3
  • EP2590533B1 patent drawingFigure 4

AI summary

The invention relates to a pull-out guide (1) for drawers or the like, comprising a carcass rail (2), a drawer rail (3) and a central rail (4) which runs differentially between the two and is guided in two rolling bearing carriages (6, 7), of which one is mounted in the carcass rail (2) and the other is mounted in the drawer rail (3), wherein the central rail (4) comprises a toothed wheel (10) and the two rolling bearing carriages (6, 7) each comprise a toothed rack (11) meshing with the toothed wheel (10), and wherein when the pull-out guide (1) is fully extended, the drawer rail (3) is pulled out beyond the carcass rail (2). According to the invention, the toothed racks (11) each comprise a toothed rack end section (13) protruding beyond the rolling bearing carriages (6, 7), wherein said section meshes with the toothed wheel (10) when the pull-out guide (1) is fully extended, and the carcass rail (2) and/or the drawer rail (3) each comprise a support (14) on which a side of the toothed rack end section (13) facing away from the toothed profile (15) is supported at least when the pull-out guide (1) is fully extended.