Split Backrest Pivot Fitting With Minimal Upholstery Gap

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Solution Overview

Problem

Seating furniture with low backrest height lacks comfort for the shoulder and head area, and existing solutions using hinges either interfere with the upholstered side or create large gaps when the upper backrest is folded, compromising the uniform coverage of furniture fabric.

Innovation Solution

The solution involves pivotally mounting downward arms with handlebars on the upper backrest part, connected to a gas spring and a stop mechanism, allowing the upper part to pivot with minimal gap and maintaining fabric continuity, while allowing the seat cushion to be pushed backward.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If hinges are arranged at the front (upholstered side), then the pivoting function is achieved, but the hinge interferes with the upholstered side

Engineering Contradiction:

Improvepivoting functionVSAvoidinterference with upholstered side

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The hinge mechanism is extracted from the front (upholstered side) and relocated to the rear side of the backrest. The fitting is mounted on the rear side of the upper backrest part, with arms extending downward to connect to the lower backrest part, completely removing the hinge from the upholstered side to eliminate interference with the upholstery fabric and appearance.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The pivoting mechanism is moved from the horizontal plane (front view) to the vertical plane (rear view). By positioning the hinge on the rear side and having arms extend downward, the mechanism operates in a different spatial dimension that does not conflict with the front upholstered surface.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If hinges are arranged at the rear, then the upholstered side is not interfered with, but a large gap arises when the upper part is folded down

Engineering Contradiction:

Improveinterference with upholstered sideVSAvoidgap between backrest parts

Core Design Contradiction:

Object-affected harmful factorsVSShape

Solution Approach 1:

The fitting is designed with asymmetric arm lengths and specific pivot point positions to create different gap characteristics at different locations. The arms are positioned and dimensioned to minimize the gap at the critical upholstered front area while allowing the rear gap to be larger, where it is not visible.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fitting allows dynamic adjustment of the gap size through its pivot mechanisms. As the upper backrest part moves between upright and folded positions, the arms rotate and adjust the relative positioning to maintain minimal gap visibility at the front while accommodating the movement at the rear.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the upper backrest part is folded down, then comfort is improved, but the furniture fabric is stretched and may form creases

Engineering Contradiction:

ImprovecomfortVSAvoidfabric stretch and creases

Core Design Contradiction:

Ease of operationVSShape

Solution Approach 1:

The fitting is designed to allow only partial folding of the upper backrest part, stopping at a predetermined angle where the fabric stretch is acceptable. The stop mechanism prevents excessive folding that would cause severe fabric distortion, while still providing sufficient comfort benefit from the folded position.

Inventive Principle:

Principle #16Partial or excessive action

4Reliability

If a fitting covers the area above the seat cushion, then the pivoting mechanism is protected, but the seat cushion cannot be pushed backwards

Engineering Contradiction:

Improvefitting protectionVSAvoidseat cushion movement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The fitting is segmented into distinct components: the main hinge mechanism is positioned above the seat cushion level where it does not interfere with cushion movement, while the arms extend downward to connect the backrest parts. This segmentation allows the upper portion to be protected while the lower portion remains clear of the seat cushion area.

Inventive Principle:

Principle #1Segmentation

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

This design achieves nearly perfect pivoting of the upper backrest with minimal fabric stretch and no creases, maintaining the overall length and providing an enlarged lying surface by allowing the seat cushion to be pulled forward.

Implementation Method 1

a gas spring (12) acts on a protruding extension (11)

Methodology Applied

Scientific EffectGas spring: Spring

Data Source

PatentEP1797796B1Fitting for moving the upper part of a split seat backrest

Publication Date: 2008.10.01 HODRY METALLWARENFABRIK R HOPPE GMBH & CO KG

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AI summary

In a fitting for pivoting the upper part (4) of a split backrest of seating furniture, which can preferably be converted into reclining furniture, two downwardly projecting arms (5, 6) are pivotably mounted on the upper part (4), one at each of their lower ends Handlebar (7, 8) is articulated. Each of these handlebars (7, 8) is pivotally mounted in the furniture frame (1) above the level (10) of the seat cushion (2). This results in a space-saving pivoting of the upper part (4).