Seating Furniture Fitting With Decoupled Leg Rest Kinematics

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Solution Overview

Problem

Existing seating furniture fittings are often heavy, expensive, and difficult to conceal due to their size, which limits flexibility and increases manufacturing complexity, especially with multi-part leg rest units that require thick padding and interfere with the construction of the furniture.

Innovation Solution

A furniture fitting with a base section, seat section, and leg rest section connected by pivot brackets and levers, allowing for relative movement between these sections, with a transmission device that decouples the movement of the seat and leg rest units to maintain a compact design and enable flexible use, featuring a drive device with an actuating lever for manual operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If known seating furniture fittings with multi-part leg rest units are used, then the leg rest unit can be extended and positioned, but the fitting becomes heavy, expensive, and bulky

Engineering Contradiction:
Improveleg rest extension capabilityVSAvoidfitting weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The fitting is divided into three distinct rigid sections (base section, seat section, leg rest section) connected by pivot brackets and levers. This segmentation allows each component to perform its specific function while keeping individual parts lightweight, resolving the contradiction between adaptability and weight.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fitting uses pivot brackets and pivot levers to create movable connections between sections, enabling the leg rest to extend and the seat to lower dynamically. This dynamic design provides the required adaptability without needing heavy fixed structures.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If known seating furniture fittings are used, then the leg rest unit can be positioned, but the fitting is expensive and manufacturing is difficult

Engineering Contradiction:
Improveleg rest positioning capabilityVSAvoidassembly difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By dividing the fitting into standardized modular sections connected by identical pivot brackets and levers, the design simplifies manufacturing and assembly. Each module can be produced independently and assembled systematically, reducing complexity despite maintaining full positioning capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pivot brackets and pivot levers serve multiple functions: connecting sections, enabling movement, and providing structural support. This multi-functionality reduces the total number of specialized components needed, simplifying both manufacture and assembly while maintaining positioning capability.

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

3Adaptability or versatility

If known seating furniture fittings are used, then the leg rest unit can be extended, but the fitting becomes bulky and difficult to conceal

Engineering Contradiction:
Improveleg rest extension rangeVSAvoidfitting volume
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The dynamic pivot connections allow the leg rest to extend along a controlled path that minimizes the space required for movement. The mechanism achieves full extension range within a compact volume by using rotational movement rather than linear extension.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

In the retracted position, the leg rest section nests underneath the seat section, minimizing the overall volume of the fitting. The compact nested design allows the mechanism to achieve full extension range while maintaining a small footprint when not in use.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Adaptability or versatility

If known seating furniture fittings are used, then the leg rest unit can be positioned, but thick padding is required which reduces flexibility

Engineering Contradiction:
Improveleg rest positioning flexibilityVSAvoidpadding thickness
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The dynamic pivot mechanism provides smooth, controlled movement between positions, eliminating the need for thick padding to absorb movement shocks or provide transition space. The controlled mechanical motion allows for thin padding while maintaining positioning flexibility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The fitting changes the movement parameter from linear displacement (requiring thick padding) to rotational movement around pivot points. This parameter change allows for compact construction with minimal padding while maintaining full positioning flexibility.

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

The solution provides a lightweight, cost-effective, and flexible furniture fitting that can be easily integrated into seating furniture, allowing for a compact design where the leg rest unit can be extended and tilted without significant lowering of the seat, enhancing user comfort and stability while minimizing visibility and manufacturing complexity.

Implementation Method 1

The three sections mentioned, the base section, the seat section and the leg rest section, are by definition rigid components which are connected to one another by means of pivot brackets and pivot levers

Methodology Applied
Scientific EffectMechanical pivoting: Hinge

Implementation Method 2

A transmission device (80) is provided for at least phase-wise kinematic coupling of the movement of the seat surface section relative to the base section with the movement of the leg rest section relative to the seat surface section

Methodology Applied
Scientific EffectKinematic decoupling: Gear

Implementation Method 3

The furniture fitting preferably has a spring device, by means of which the seat surface section and the leg rest section are subjected to spring force against one another

Methodology Applied
Scientific EffectElastic force: Spring

Implementation Method 4

a drive device, by means of which a first of the pivoting levers is driven, in particular manually by means of an actuating lever (66) for manual actuation

Methodology Applied
Scientific EffectMechanical leverage: Lever

Data Source

PatentEP3284370B1Fitting for an item of seating furniture and item of seating furniture with such a fitting
Publication Date: 2019.03.13 BEHEERKLN VERMEULEN BEESD BV
  • EP3284370B1 patent drawingFigure 1~2
  • EP3284370B1 patent drawingFigure 3
  • EP3284370B1 patent drawingFigure 4A~4B

AI summary

The invention relates to a furniture fitting (20) for a piece of seating furniture (100). It is proposed that the furniture fitting (20) has a base section (30) for attaching to a piece of furniture base (130) standing on a floor, a seat section (50) for attaching a seat unit (150) with a seat (152) and a leg rest section (70 ) for attaching a leg rest unit (170) with a leg rest surface (172). The seat section (50) is movably attached to the base section (30) between an upper and a lower end position and the leg rest section (70) is movably attached to the seat section (50) between a stowed end position and a use end position, the leg rest section ( 70) is attached to the seat section (50) by means of a rear and a front pivoting lever (60, 62). A transmission device (80) is provided for at least phased kinematic coupling of the movement of the seat section (50) relative to the base section (30) with the movement of the leg rest section (70) relative to the seat section (50).