Drawer Pull-Out Rail Mechanism for Heavy Load Stability

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Solution Overview

Problem

Existing pull-out mechanisms for large and heavy drawers in furniture are complex and vulnerable due to the use of multiple bearing balls, making them unreliable for both horizontal and vertical loads.

Innovation Solution

A simplified pull-out mechanism using a single bearing ball and two perpendicular rollers in a bearing holder on one side, with a horizontal auxiliary roller between the intermediate and upper/lower rails, allowing for reliable handling of both horizontal and vertical loads, and optionally removing the lower rail for further simplification by affixing the intermediate rail to the wall.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If multiple bearing balls are used in the pull-out mechanism, then the drawer can support vertical loads, but the structure becomes complex and vulnerable

Engineering Contradiction:
Improveload bearing capacityVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines multiple bearing elements (rollers and bearing balls) into a single integrated bearing holder assembly. This merging approach maintains the load-bearing capability while reducing the number of separate components and simplifying the overall structure, directly addressing the contradiction between strength and device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bearing holder is designed to perform multiple functions simultaneously: it supports vertical loads through bearing balls, handles horizontal loads through rollers, and provides structural integration. This multi-functionality allows a single component to replace what would otherwise require multiple separate elements, reducing complexity while maintaining strength

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

2Strength

If multiple bearing balls are used in the pull-out mechanism, then the drawer can support vertical loads, but the mechanism becomes vulnerable

Engineering Contradiction:
Improveload bearing capacityVSAvoidmechanism reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By merging the bearing balls and rollers into a single integrated bearing holder, the patent reduces the number of potential failure points. Fewer separate components mean fewer interfaces and mounting points that could fail, thereby improving reliability while maintaining the load-bearing capacity through the combined bearing elements

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the lower rail is removed and the intermediate rail is affixed to the wall, then the structure is simplified, but the ability to handle heavy loads may be compromised

Engineering Contradiction:
Improvenumber of railsVSAvoidload bearing capacity
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent extracts and removes the lower rail from the system, simplifying the structure to only two rails (upper and intermediate). The load-bearing function previously distributed across three rails is redistributed to the remaining two rails through strategic placement of bearing holders, maintaining strength while reducing complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The intermediate rail serves as a mediator that takes on additional functionality. By affixing it to the wall and strategically positioning bearing holders along its length, it compensates for the removed lower rail's load-bearing capacity, enabling the system to handle heavy loads with fewer components

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 mechanism achieves reliable operation for both pulling out and pushing in heavy drawers, ensuring stability and ease of manufacturing, with the ability to handle significant weights and prevent furniture tilting.

Implementation Method 1

at least one bearing holder with rollers and balls is inserted between the intermediate rail and the upper rail and the lower rail respectively

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2114206B1Pull-out mechanism for a drawer
Publication Date: 2012.06.20 INTER IKEA SYST
  • EP2114206B1 patent drawingFigure 1
  • EP2114206B1 patent drawingFigure 2
  • EP2114206B1 patent drawingFigure 3

AI summary

A pull-out mechanism for a drawer (2) in a drawer cavity (3) in a piece of furniture (4). The pull-out mechanism includes an upper rail (8) with a substantially U-shaped cross- section, said rail being affixed to the drawer (2) in its longitudinal direction, and possibly a lower rail (8) with a substantially U-shaped cross section, said lower rail, possibly indirectly, being affixed to a wall (5) in the drawer cavity (3), and an intermediate rail (10) which in its longitudinal direction is movable between the upper rail and the lower rail. At least one bearing holder (12, 22) with roller (14, 15, 24, 25) and balls (16, 29) is inserted between the intermediate rail and the upper rail and the lower rail respectively. Exactly one bearing ball (16, 29) is mounted in the part of the individual bearing holder (12, 22) placed on one side of the intermediate rail (10); two rollers or wheels (14, 15, 24, 25) are mounted in the part of the individual bearing holder (12, 22) placed on the other side of the intermediate rail (10). The axes of rotation of said rollers or wheels are placed in each their plane of two planes standing perpendicular to each other. A substantially horizontal auxiliary roller (18, 28) extending to both sides of the intermediate rail (10) is mounted in the individual bearing holder (12, 22) between the intermediate rail (10) and the upper rail (6) and the lower rail (8) respectively. Hereby a considerably constructive simplification is achieved and the pull-out mechanism can bear both horizontal and vertical loads in a reliable way. Furthermore it is possible to pull out the drawer to a position just outside the actual piece of furniture.