Pivot fitting and furniture

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Solution Overview

Problem

Existing swivel fittings for movable furniture parts face issues such as protruding crank gears that damage upholstery, jamming due to load-induced bending of crank lugs and four-bar linkages, and reduced displacement range beyond 90°, which affect the functionality and durability of the furniture.

Innovation Solution

A swivel fitting with a first and second lever mounted pivotably about a pivot axis, featuring a chain or belt drive mechanism that allows for adjustable angular positions and includes an overload protection system to prevent damage from excessive loads, ensuring even displacement and increased load absorption capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If crank gears are used to displace the fastening part linearly, then the fastening part can be adjusted in the longitudinal direction of the second lever, but the crank protrudes beyond the installation space and may damage the upholstery

Engineering Contradiction:
Improveadjustability of fastening partVSAvoidupholstery damage from protruding crank
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent transitions from a crank mechanism requiring radial protrusion to a chain/belt drive where the drive shaft and pulleys are arranged in-plane on the second lever. The chain or belt transmits motion without requiring the mechanism to extend beyond the lever's footprint, effectively solving the upholstery damage issue while maintaining adjustment functionality.

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

2Ease of operation

If crank lugs and four-bar linkages are used for displacement, then the fastening part can be adjusted, but under load the components bend and the swivel fitting jams

Engineering Contradiction:
Improveadjustability of fastening partVSAvoidjamming under load
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the crank-lug-four-bar linkage mechanical system with a chain or belt drive system coupled to a drive shaft. This substitution eliminates the bending and jamming issues by using a more robust transmission mechanism where the chain or belt flexibly transmits force without the rigid linkages that are prone to deformation under load.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the initial position is set to more than 90°, then the displacement range is reduced because the crank link connection position is fixed

Engineering Contradiction:
Improveinitial position flexibilityVSAvoiddisplacement range
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent makes the drive shaft rotatable on the second lever, allowing dynamic adjustment of the chain or belt drive connection position. This rotational freedom enables the system to accommodate different initial angles (greater than 90°) while maintaining full displacement range, as the drive shaft can be positioned optimally for each application scenario.

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

The swivel fitting provides a longer displacement range and improved load absorption without damaging components, ensuring smooth and even adjustment over the entire range while preventing damage from excessive loads, thus enhancing the usability and durability of the furniture.

Implementation Method 1

a chain or belt drive or cable pull coupled to the fastening part

Methodology Applied
Scientific EffectChain drive: Chain

Implementation Method 2

a chain or belt drive or cable pull coupled to the fastening part

Methodology Applied
Scientific EffectBelt drive:

Implementation Method 3

a drive unit which is arranged on the first lever and is coupled to the chain or belt drive or cable pull and with which the fastening part can be driven by swiveling the second lever

Methodology Applied
Scientific EffectMechanical transmission: Mechanical Advantage

Implementation Method 4

a first lever (2) and a second lever (3), which are mounted about a common pivot axis (D) from a basic position by a predetermined angle α pivotable to one another

Methodology Applied
Scientific EffectPivot joint: Hinge

Data Source

PatentEP3400834B1Pivot fitting and furniture
Publication Date: 2020.10.14 HETTICH FRANKE
  • EP3400834B1 patent drawingFigure 1
  • EP3400834B1 patent drawingFigure 2
  • EP3400834B1 patent drawingFigure 3

AI summary

A pivot fitting, in particular for movable furniture parts on upholstered furniture, has a first lever (2) and a second lever (3) which are mounted pivotable to one another about a common axis (D) from a basic position by a predetermined angle (α), an adjusting mechanism (24) with which the two levers (2, 3) can be fixed in different angular positions within the predetermined angle (α) relative to one another, a displaceable on the second lever (3) in the longitudinal direction (L3) of the second lever (3). held fastening part (4), a chain or belt drive or cable pull arranged on the second lever (3) and coupled to the fastening part (4), a drive unit (5 ), with which the fastening part (4) can be driven by pivoting the second lever (3). A piece of furniture is also described.