Furniture Pull-Out Rail Layout for Compact Smooth Guidance

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Solution Overview

Problem

Existing guides for sliding elements in kitchen furniture, such as drawers and food carriers, face challenges in meeting complex requirements while being compact and reliable, particularly in applications like ovens and refrigerators, where they need to provide low-noise and low-friction movement over extended lengths.

Innovation Solution

A guide device with a support rail, a pull-out rail, and a central rail, featuring load-transmitting bearing means with concave and convex surfaces, allowing for smooth and jerk-free displacement through the interaction of bearing rollers and roller bearing elements, which are arranged vertically to save space and ensure reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the guide device uses traditional bearing arrangements, then the structure is simpler, but the horizontal width increases and the movement becomes noisier

Engineering Contradiction:
Improvehorizontal width of guide deviceVSAvoidcomplexity of bearing arrangement
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent transitions from horizontal arrangement of bearing rollers and roller bearing elements to a vertical arrangement on opposite sides of the web section. This dimensional change allows the components to be stacked vertically rather than placed side-by-side horizontally, significantly reducing the horizontal width of the guide device while maintaining all necessary bearing functions

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

Solution Approach 2:

The bearing rollers and roller bearing elements are nested in a vertical stack on opposite sides of the web section, with each component positioned at different vertical levels. This nesting arrangement allows multiple bearing elements to occupy a compact vertical space, reducing the overall horizontal footprint of the guide device

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If the bearing rollers and roller bearing elements are arranged horizontally side by side, then the structure is simpler, but the horizontal width of the device increases

Engineering Contradiction:
Improvesimplicity of component arrangementVSAvoidhorizontal width of guide device
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The patent repositions the bearing rollers and roller bearing elements from a horizontal side-by-side arrangement to a vertical stacked arrangement on opposite sides of the web section. This moves the components into the vertical dimension, freeing up horizontal space and reducing the overall width of the guide device

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

3Volume of moving object

If the guide device uses a compact design with vertical arrangement, then the horizontal width is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvehorizontal width of guide deviceVSAvoidprecision of bearing surface alignment
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The bearing rollers and roller bearing elements utilize concave and convex bearing surfaces that are precisely formed with curved geometries. These spherical or curved surfaces provide self-aligning characteristics that compensate for minor manufacturing variations, ensuring smooth rolling contact and reliable load transmission despite the compact vertical arrangement

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent employs specific geometric parameters for the concave and convex bearing surfaces, including precise curvature radii and engagement depths. By optimizing these parameters, the design achieves both compact dimensions and sufficient manufacturing tolerance, balancing space reduction with manufacturability

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If the bearing rollers and roller bearing elements are placed on the same side of the web section, then the structure is simpler, but the horizontal width increases and movement smoothness decreases

Engineering Contradiction:
Improvesimplicity of structural arrangementVSAvoidsmoothness of rail displacement
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent employs an asymmetric arrangement where bearing rollers and roller bearing elements are positioned on opposite sides of the web section rather than symmetrically on the same side. This asymmetric placement creates a balanced load distribution across the web section, improving structural stability and ensuring smooth, jerk-free displacement of the rails

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

By placing bearing rollers on one side of the web section and roller bearing elements on the opposite side, the design creates a counterbalancing effect. The loads are distributed symmetrically across the web section, preventing uneven stress concentration and ensuring smooth, stable movement without jerks or binding

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 solution enables a compact, space-saving, and reliable guide system that achieves low-noise and jerk-free displacement, optimizing the accommodation and positioning of roller bearing elements for smooth movement, while maintaining structural integrity and durability.

Implementation Method 1

the bearing rollers and the roller bearing elements roll on the same section or the web section of the center rail

Methodology Applied
Scientific EffectRolling: Roller

Implementation Method 2

a low-noise and low-friction linear displacement movement of the center rail and the extension rail

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP2904940B1Device for guiding a pull-out and piece of furniture with such a device
Publication Date: 2018.07.04 GRASS GMBH
  • EP2904940B1 patent drawingFigure 1~2
  • EP2904940B1 patent drawingFigure 3~5
  • EP2904940B1 patent drawingFigure 6

AI summary

A device for guiding a pusher element is proposed, which can be slidably moved by means of the device on a wall section, the device comprising a carrier rail (2), an extension rail (4) and a middle rail (3) and storage means. According to the invention, the bearing means have at least three bearing rollers (14) with a concavely shaped bearing surface (15) and roller bearing elements, each with a convexly shaped bearing surface, with load transmission of the bearing means taking place via the bearing surfaces (15), and with the center rail (3) a web section (16, 17) is formed, with the first and second running surfaces (16b, 17b, 16a, 17a) being spaced apart from one another over the material thickness of the web section (16, 17), so that when the rails are displaced, the bearing rollers (14 ) interact via the concave bearing surface (15) with a section of the inside second running surface (16a, 17a) and the roller bearing elements roll over the respective convex bearing surface on a section of the outside first running surface (16b, 17b).