Dynamic Lumbar Support Mechanism for Rocking Chair Posture

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Solution Overview

Problem

Conventional office and home chairs with rocking mechanisms fail to provide adequate support for the user's lower back when the chair rocks forward, leading to potential back pain and discomfort due to lack of lumbar support.

Innovation Solution

A dynamic lumbar support system is integrated into the chair, featuring a resilient foam cushion with a flexible, spring-memory plastic sheet that changes shape in response to user pressure, using a rotatable sheet bending rod and tension strap mechanism to maintain proper posture both when the chair is upright and when reclined.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the chair back stands upright to enable the user to sit erect close to the work surface, then the user can work efficiently, but the user's lower back lacks support and posture deteriorates

Engineering Contradiction:
Improvework efficiencyVSAvoidback pain and discomfort
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The lumbar support is designed to be dynamic rather than static. The resilient cushion back support can change its shape and position in response to user pressure, automatically adapting to provide support when needed and receding when not in use, thus resolving the contradiction between maintaining an upright working position and providing lumbar support

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The lumbar support system is self-actuating through the resilient cushion and flexible sheet mechanism. When the user leans back, the cushion compresses and the flexible sheet straightens, automatically engaging the support without requiring user intervention or complex control systems, thereby providing back support during work without compromising productivity

Inventive Principle:
Principle #25Self-service

2Ease of operation

If the chair rocks back and forth to enable the user to relax, then the user can comfort, but the lumbar support must adapt to changing positions

Engineering Contradiction:
Improveuser comfortVSAvoidlumbar support adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The lumbar support uses a dynamic mechanism with the resilient cushion and flexible force-receiving sheet that automatically adapts to different chair positions. When the chair rocks back, the cushion compresses and the sheet straightens to maintain support; when the chair returns to upright, the cushion expands and the sheet curves again, providing continuous adaptability throughout the rocking motion

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes its physical parameters (shape, position, compression level) in response to user weight shifts and chair position changes. The resilient cushion varies its compression state and the flexible sheet varies its curvature, allowing the lumbar support to maintain effectiveness across different rocking positions and comfort levels

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If a resilient cushion back support is used to provide lumbar support, then proper posture is maintained, but the support must be compressed by user pressure to function

Engineering Contradiction:
Improveback posture stabilityVSAvoiduser pressure requirement
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The flexible force-receiving sheet acts as an intermediary between the user's back pressure and the resilient cushion back support. The sheet transfers and amplifies the user's weight-induced pressure onto the cushion, ensuring that even mild leaning motions generate sufficient compression to engage the lumbar support and maintain stable posture

Inventive Principle:
Principle #24Intermediary (Mediator)

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 dynamic lumbar support system effectively maintains a proper back posture and reduces discomfort by providing continuous support to the user's lower back, regardless of the chair's position, enhancing comfort during long working periods.

Implementation Method 1

A flexible (e.g., plastic) force-receiving sheet, having a spring memory and a normally-curved (i.e., arced) configuration is bonded to the rear of the cushion back support

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the flexible, normally-curved force-receiving sheet which covers the rear of the back support is straightened so as to store energy

Methodology Applied
Scientific EffectSpring memory: Elastic Recovery

Implementation Method 3

The dynamic lumbar support includes a resilient (e.g., foam) cushion back, support that is located inside the back of the chair

Methodology Applied
Scientific EffectResilience: Elasticity

Implementation Method 4

the convex cushion back support is compressed and flattened by the user's back

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentUS9357849B2Dynamic lumbar support for a chair
Publication Date: 2016.06.07 GROVE JAMES E

AI summary

A dynamic lumbar support located within the back of an office or home chair to enable a user to be seated close to a work surface (e.g., a desk or a table). The chair back rocks back and forth when the user shifts his weight backwards and forwards. The dynamic lumbar support includes a cushion back support manufactured from a resilient material that is responsive to a compressive force applied thereto when the user reclines and shifts his weight against the chair back. In particular, the cushion back support is adapted to change its shape from a relaxed convex shape at which to support the user's lower back and maintain a proper posture when the user sits erect and the chair back stands upright to a compressed flattened shape at which to support the user's back when he reclines and the chair back tilts backwards.