Sofa Bed Sliding System Using Lipophilic Coating to Replace Bearings

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Solution Overview

Problem

Existing sofa bed sliding systems require expensive components like guiding rails, bearings, and low-friction rollers to ensure smooth movement, making them costly and inefficient for manufacturing and operation.

Innovation Solution

A novel sofa bed sliding system utilizing a sliding surface coated with a lacquer comprising a resin and a lipophilic composition coating, applied to aluminum or steel bars, which provides low friction and reduces the need for expensive components by using a linear plain bearing with a contact pressure of at least 4 N/mm² and a contact area of less than 3 mm².

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If guiding rails, bearings, and low-friction rollers are used to ensure smooth movement, then the sliding functionality is improved, but the manufacturing cost and device complexity increase

Engineering Contradiction:
Improvesmooth movementVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of low-friction sliding by removing complex mechanical components (guiding rails, bearings, rollers) and retaining only the critical sliding interface. The seating portion directly slides on the support structure with a simple coating applied to the contact surface, eliminating unnecessary intermediate components while preserving the core sliding functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, complex mechanical components with a simple, cost-effective coating applied to the sliding surface. The coating (such as PTFE, silicone, or wax) is a inexpensive material that can be easily applied and reapplied, providing low-friction properties without the need for precision-engineered mechanical parts that require costly manufacturing and maintenance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Ease of operation

If guiding rails and bearings are used to provide low friction, then the sliding performance is improved, but the manufacturing cost increases

Engineering Contradiction:
Improvesliding performanceVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent changes the surface properties of the sliding interface by applying a low-friction coating rather than using precision mechanical components. This parameter change (surface friction coefficient) achieves the desired sliding performance through material property modification instead of complex mechanical design, significantly reducing manufacturing costs while maintaining functionality.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If expensive components like guiding rails and bearings are used, then the reliability of sliding movement is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvesliding reliabilityVSAvoidcomponent complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-lubricating system where the coating on the sliding surface provides continuous low-friction properties without requiring external lubrication or complex mechanical components. The coating material (such as PTFE or silicone) inherently provides lubrication, making the system self-sufficient and reliable without the need for precision-engineered bearings or guiding rails that require maintenance and lubrication.

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

The system achieves low friction and cost-effective operation while maintaining robustness, allowing for easy conversion between sofa and bed positions with reduced wear and tear, and long-lasting performance without the need for frequent lubrication.

Implementation Method 1

The lacquer is in turn at least partly coated with a lipophilic composition coating to provide a slide layer with lowered friction

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

The sliding surface may for example be formed on an aluminum bar, e.g. aluminum profile, preferably having an anodized oxide surface layer

Methodology Applied
Scientific EffectAnodizing: Anodising

Implementation Method 3

Steel surfaces may be lacquered by electrocoating or autodeposition to provide a lacquer layer with uniform thickness

Methodology Applied
Scientific EffectElectrocoating: Electrostatic Deposition

Data Source

PatentEP3346880B1A sofa bed, and a sofa bed sliding system for such sofa bed
Publication Date: 2021.08.18 IKEA SUPPLY AG
  • EP3346880B1 patent drawingFigure 1~2
  • EP3346880B1 patent drawingFigure 3~4
  • EP3346880B1 patent drawingFigure 5

AI summary

A sofa bed sliding system (100, 200, 300, 400, 500, 600, 700) for a sofa bed (1,1') is provided. Thesliding system is forming a connection between a moveable sofa bed part (3, 3') and an associated frame structure (10, 10'), wherein said sliding system (100, 200, 300, 400, 500, 600, 700) comprises at least one sliding surface (110, 210, 310, 410, 510, 610) being coated with a lacquer comprising a resin, wherein said lacquer in turn is at least partly coated with a lipophilic composition coating to provide a slide layer with a lowered friction.