Elastic Sheet Backrest Structure for Head-Leaning Comfort

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Solution Overview

Problem

Conventional backrest chairs with rigid frame members fail to provide comfort by not allowing the head to lean backward relative to the shoulders and do not wrap around the body effectively when a load is applied, leading to a strained sitting experience.

Innovation Solution

A backrest chair with a chair sheet material composed of a core sheet and a buffer sheet, both capable of elastic bending deformation, is attached to a chair support frame, allowing the backrest to elastically displace and support the body while enabling the head to lean backward, with the core sheet made of mesh sheets and shape retaining materials like carbon fiber for added resilience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid frame members are used to construct the backrest, then structural strength is improved, but comfort and body wrapping capability deteriorate

Engineering Contradiction:
Improvebackrest structural strengthVSAvoidbody wrapping capability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent replaces rigid frame members with a flexible sheet material that has elastic bending deformation capability. This sheet material can wrap around the user's body contours while maintaining sufficient structural strength, directly resolving the contradiction between strength and body wrapping capability.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The backrest uses a composite structure combining a core sheet with shape retaining materials and mesh sheets. This composite material provides both the necessary structural strength and the flexibility to wrap around the body, achieving both contradictory requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the entire backrest is constructed of highly rigid frame members, then structural stability is improved, but head leaning capability deteriorates

Engineering Contradiction:
Improvebackrest stabilityVSAvoidhead leaning capability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The flexible sheet material allows the head portion to lean backward relative to the shoulders by elastically deforming, while the overall backrest maintains stability through its elastic resilience and attachment to the chair frame.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The backrest transitions from a static rigid structure to a dynamic flexible structure that can adapt its shape in response to user movements. The sheet material dynamically adjusts to allow head leaning while maintaining backrest stability through elastic recovery.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If rigid frame members are used, then manufacturing precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveframe assembly precisionVSAvoidbackrest assembly ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent merges multiple separate frame members into a single integrated sheet material component. This eliminates the need for precise assembly of multiple parts, greatly simplifying manufacturing while maintaining the required structural precision through the sheet material's inherent properties.

Inventive Principle:
Principle #5Merging (Combining)

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 chair provides a comfortable sitting experience by allowing the head to lean back relative to the shoulders and wrapping around the body, reducing strain and improving support, while being easy to manufacture and assemble at a lower cost.

Implementation Method 1

a core sheet is formed by attaching a shape retaining material capable of elastic bending deformation to mesh sheets capable of elastic bending deformation, to have an elastic resilience for assuming a backrest shape in a natural state and to be elastically displaceable while maintaining a backrest state by a stretching force in a use situation

Methodology Applied
Scientific EffectElastic bending deformation: Elasticity

Implementation Method 2

the core sheet is formed of a shape retaining material made capable of elastic bending deformation by a high-strength carbon fiber sheet

Methodology Applied
Scientific EffectComposite material strength: Composite Materials

Data Source

PatentEP2583590B1Chair with backrest
Publication Date: 2015.10.07 MIYAMOTO SEIZOU
  • EP2583590B1 patent drawingFigure 1
  • EP2583590B1 patent drawingFigure 2
  • EP2583590B1 patent drawingFigure 3

AI summary

[Problem] To provide a comfortable chair with a backrest. [Solution] A chair with a backrest characterized by comprising core sheets (9, 12, 13, 14) and a chair sheet material (103), and in that the chair sheet material (103) is attached to chair support frames (20, 21, 22, 23, 24, 25). The core sheets (9, 12, 13, 14) are formed of an elastically bendable material, have elastic resilience so as to naturally assume a backrest shape, and also can be elastically displaced by a stretching force during use while a backrest state is maintained. The chair sheet material (103) is provided with buffer sheets (15, 16) which overlap the surface of the core sheets at the side facing the back of a seated person during use. The chair support frames (20, 21, 22, 23, 24, 25) are lower than a seating surface and have the chair sheet material attached thereto in a state where the core sheets and the buffer sheets are positioned at the rear surface of the back and head of the seated person.