Pull-Out Guide Rail Structure for High Tilting Moment Loads

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Solution Overview

Problem

Existing pull-out guides for furniture parts struggle to absorb high tilting moments while maintaining a low overall height, especially when handling heavy loads, leading to potential bending of guide rails and limited load capacity.

Innovation Solution

The use of roller-shaped rolling elements with linear contact areas between the center rail and body rail, combined with a compact prismatic guide design featuring inclined outer rolling element raceways and vertical or horizontal rolling element tracks, allows for efficient force distribution and absorption of tilting moments, while maintaining a low vertical distance between guide rails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If roller-shaped rolling elements are used to absorb tilting moments, then load capacity is improved, but the guide rails may bend under heavy loads

Engineering Contradiction:
Improveload capacityVSAvoidguide rail stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent introduces a vertical dimension by forming a leg on the center rail that extends downward to partially encompass the body rail. This vertical structure provides an additional dimension for force distribution, allowing the rolling elements to absorb tilting moments more effectively without overloading the horizontal guide rail sections.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The guide rail system is segmented into multiple functional sections: the body rail, the center rail with its horizontal section and downward leg, and the running rail. This segmentation allows each component to specialize in handling specific forces - the horizontal sections manage lateral guidance while the vertical leg handles vertical and tilting loads, preventing bending of the main guide rails.

Inventive Principle:
Principle #1Segmentation

2Length of stationary object

If the vertical distance between guide rails is reduced, then overall height is minimized, but the ability to absorb tilting moments is limited

Engineering Contradiction:
Improveoverall heightVSAvoidtilting moment absorption
Core Design Contradiction:
Length of stationary objectVSStrength

Solution Approach 1:

Instead of increasing the vertical distance between the body rail and running rail to absorb tilting moments, the patent uses another dimension by extending the center rail downward to form a leg that encompasses the body rail. This allows tilting moment absorption within a compact vertical envelope.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The downward leg of the center rail is pre-positioned to partially encompass the body rail before any tilting moment is applied. This preliminary structural arrangement ensures that rolling elements are already in place to absorb tilting forces, preventing guide rail bending while maintaining low overall height.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If point contact rolling elements are used, then the structure is simple, but the raceway can be damaged under heavy loads

Engineering Contradiction:
Improvestructure simplicityVSAvoidraceway durability
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent changes the contact parameter from point contact to linear contact by using roller-shaped rolling elements with their longitudinal axes oriented perpendicular to the direction of motion. This parameter change increases the contact area between rolling elements and raceway, distributing loads more evenly and preventing raceway damage while maintaining relatively simple structure.

Inventive Principle:
Principle #35Parameter changes

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 enables the pull-out guide to effectively absorb high tilting moments and support heavy loads over the entire pull-out path with a low overall height, enhancing load capacity and stability without increasing material thickness or weight.

Implementation Method 1

roller-shaped rolling elements arranged between the center rail and the body rail with essentially the entire length of the rollers is available for power transmission

Methodology Applied
Scientific EffectRolling contact: Roller

Implementation Method 2

When balls are used as rolling elements, there is usually only point contact between the ball track and the raceway, which can damage the raceway if the drawer slide is heavily loaded

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3054812B1Pull-out guide for movable furniture parts
Publication Date: 2018.07.25 PAUL HETTICH GMBH & CO KG
  • EP3054812B1 patent drawingFigure 1
  • EP3054812B1 patent drawingFigure 2a~2b
  • EP3054812B1 patent drawingFigure 2c~2d

AI summary

The invention relates to a pull-out guide for movable furniture parts, in particular drawers, having a basic-structure rail (10), a C-shaped centre rail (20) and a running rail (30), which can be fastened on the furniture part, wherein the C-shaped centre rail (20) has inwardly oriented inner rolling-body tracks (21', 22') for roller-form rolling bodies (41, 43, 44, 46, 47), which are arranged between the centre rail (20) and the basic-structure rail (10), and also has at least two outwardly oriented and outwardly inclined outer rolling-body tracks (22''), which are spaced apart from one another by a horizontal portion (21) of the centre rail (20) and are intended for further roller-form rolling bodies (51, 52, 53, 54), which are arranged between the centre rail (20) and the running rail (30). The pull-out guide is distinguished in that the C-shaped centre rail (20) has formed on it a free limb (26) which engages partially around the basic-structure rail (10), wherein a further inner rolling-body track (26') for roller-form rolling bodies (42), which are arranged between the centre rail (20) and the basic-structure rail (10), is formed on the inner side of the limb (26).