Drawer Pull-Out Rail Layout for Load-Shifting Roller Support

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Solution Overview

Problem

Existing pull-out runner systems for drawers face issues with deformation of plastic rollers under high loads, leading to impaired running behavior due to uneven loading and potential tilting, as the foremost rollers are subjected to significant stress.

Innovation Solution

The system redistributes load by using a smaller diameter first rolling element that supports the drawer when closed and is relieved when open, with an elevation on the drawer rail ensuring vertical loading only on this element, while larger rolling elements handle the drawer's movement when open, preventing deformation and maintaining smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If plastic rollers are used as rolling elements to enable smooth operation, then the drawer can run smoothly, but the rollers become deformed under high loads when the drawer is closed

Engineering Contradiction:
Improvesmooth runningVSAvoidroller deformation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The carriage is divided into two distinct types of rolling elements: first rolling elements with smaller diameter for closed position support, and second rolling elements with larger diameter for open position rolling. This segmentation allows each type to be optimized for its specific function, preventing deformation while maintaining smooth operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different rolling elements are assigned different diameters based on their local functional requirements. The first rolling elements have smaller diameter specifically for bearing vertical loads in closed position, while second rolling elements have larger diameter for smooth rolling in open position. This local differentiation resolves the contradiction between load-bearing capacity and rolling smoothness.

Inventive Principle:
Principle #3Local quality

2Force

If the foremost rolling elements are designed to support the drawer in closed position, then vertical load is borne, but the rolling elements are subjected to considerable mechanical stresses causing deformation

Engineering Contradiction:
Improveload bearing capacityVSAvoidroller deformation
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The rolling elements are segmented into two categories with different design characteristics. First rolling elements are specifically designed with smaller diameter for vertical load support in closed position, while second rolling elements are designed with larger diameter for rolling function. This segmentation allows the first rolling elements to bear loads without deforming, as they are not required to perform rolling function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different rolling elements based on drawer position. In closed position, first rolling elements bear the load; in open position, second rolling elements perform rolling. This dynamic allocation of functions prevents any single rolling element from being subjected to both high load and rolling stresses simultaneously.

Inventive Principle:
Principle #15Dynamics

3Force

If multiple rolling elements are used to support the drawer, then load distribution is improved, but all rolling elements are loaded simultaneously causing potential tilting and instability

Engineering Contradiction:
Improveload distributionVSAvoidlateral stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The loading configuration is made dynamic based on drawer position. In closed position, only first rolling elements are loaded while second rolling elements are released. In open position, the load transfers to second rolling elements. This dynamic loading pattern prevents simultaneous loading of all rolling elements, eliminating the risk of tilting and instability while maintaining proper load distribution.

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

This configuration reduces deformation of rolling elements, enhances running stability, and prevents tilting by ensuring the foremost rolling element is only loaded vertically when the drawer is closed, while larger elements handle the load when open, maintaining smooth operation and preventing jerky movements.

Implementation Method 1

a first and at least one second rolling element... allow the drawer or a shelf to run smoothly

Methodology Applied
Scientific EffectRolling friction: Friction

Data Source

PatentEP1959794B2Pull-out guide system for drawers
Publication Date: 2015.04.08 JULIUS BLUM GMBH
  • EP1959794B2 patent drawingFigure 1a~1b
  • EP1959794B2 patent drawingFigure 2a~2b
  • EP1959794B2 patent drawingFigure 3

AI summary

Pull-out guide system (1) for drawers, having a basic-structure rail (2), a drawer rail (3) and, if appropriate, having a centre rail arranged between these two rails (2, 3), wherein the load of the drawer is transmitted by way of a first rolling-contact body (4) and at least one second rolling-contact body (5a), wherein the first rolling-contact body (4) has a smaller diameter than the at least one second rolling-contact body (5a), and wherein the drawer rail (3) is designed such that, when the drawer is in the closed state, the first rolling-contact body (4) is subjected to loading by the drawer rail (3) and, when the drawer is opened, the first rolling-contact body is relieved of the loading of the drawer rail (3).