Chair Footrest Pivot Fitting Layout for Ground Clearance

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Solution Overview

Problem

Existing swivel fittings for seating furniture are complex, expensive, prone to malfunction, and often limit ground clearance due to their design, failing to meet high aesthetic and functional requirements.

Innovation Solution

The adjusting lever and control lever of the swivel fitting are arranged adjacent to each other in a common longitudinal section extending at least 20 cm, perpendicular to each other, with an inclination of less than 15°, allowing for a compact and efficient design that maximizes ground clearance and aesthetic appeal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional swivel fittings are used for adjusting the footrest, then the footrest can be positioned, but the design becomes complex and expensive, and ground clearance is limited

Engineering Contradiction:
Improvefootrest adjustment reliabilityVSAvoidswivel fitting complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the adjusting lever and control lever into a single integrated mechanism where both levers move in a common longitudinal section. This merging of functions reduces the overall complexity of the swivel fitting while maintaining the footrest adjustment capability, directly addressing the contradiction between reliability and device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common longitudinal section serves multiple functions: it guides both the adjusting lever and control lever simultaneously, provides structural support, and enables the footrest to achieve both elevation and forward positioning. This multi-functionality reduces the need for separate complex mechanisms, resolving the contradiction between reliable adjustment and device complexity

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

2Ease of operation

If traditional swivel fittings are used for adjusting the footrest, then the footrest can be adjusted, but the ground clearance is reduced

Engineering Contradiction:
Improvefootrest adjustabilityVSAvoidground clearance
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent utilizes the longitudinal section extending perpendicular to the levers to create additional spatial dimension for the adjustment mechanism. This allows the footrest to be elevated and positioned forward without requiring excessive vertical space, thereby maintaining ground clearance while preserving ease of operation

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

Solution Approach 2:

The mechanism allows the footrest to dynamically transition between retracted and extended positions through the coordinated movement of adjusting and control levers in the common longitudinal section. This dynamic adjustment capability maintains ground clearance during retraction while enabling easy operation during extension

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If complex swivel fittings are used, then footrest adjustment is possible, but the fittings are prone to malfunction and expensive

Engineering Contradiction:
Improvefootrest position adaptabilityVSAvoidswivel fitting reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

By merging the adjusting and control lever functions into a single integrated mechanism with a common longitudinal section, the patent reduces the number of separate moving parts that could potentially malfunction. This simplification maintains position adaptability while improving reliability and reducing cost

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4140361B1Pivoting fitting of a chair for adjusting a foot part and chair with adjustable foot part
Publication Date: 2026.03.04 LUSCH GMBH
  • EP4140361B1 patent drawingFigure 1A
  • EP4140361B1 patent drawingFigure 1B
  • EP4140361B1 patent drawingFigure 1C

AI summary

Described and illustrated is a pivot fitting (2) of a seating furniture (1) for adjusting a footrest (3) from a retracted non-use position to an extended use position, comprising a mounting section (10) for mounting on a chassis (6) of the seating furniture (1), a footrest section (43) for mounting the footrest (3), and a footrest fitting (4) for adjusting the footrest (3), wherein the footrest section (43) has a footrest connection pivot area (19) that is forward in the use position and rear in the non-use position, and a footrest connection tilt area (20) that is rear in the use position and front in the non-use position, and wherein the footrest connection pivot area (19) and the footrest connection tilt area (20) are held and adjustable relative to each other by means of an adjusting lever (39) and a control lever (42) of the footrest fitting (4).In order to better meet the requirements placed on seating furniture and to simultaneously manufacture the swivel fitting cost-effectively and use it reliably, it is provided that the adjusting lever (39) and the control lever (42) are arranged adjacent to each other in a common longitudinal section (50) extending at least 20 cm in the longitudinal direction of the swivel fitting (2) during the entire adjustment from the non-use position to the use position and back, in a direction at least substantially perpendicular to the adjusting lever (39) and/or to the control lever (42), that the longitudinal section (50) is arranged in front of the foot section connection tilting area (20) in the non-use position, and that in the longitudinal section (50) the longitudinal extension of the adjusting lever (39) is inclined by less than 15° relative to the longitudinal extension of the control lever (42).