Chair Backrest with Planar Rigid Support for Straight Spinal Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional chair backrests fail to straightly support the spinal column, leading to lumbago and fatigue due to backward tilting of the pelvis and curvature of the lumbar portion, as they do not account for the natural anatomical protrusions and recessions of the human back, resulting in uneven pressure distribution and poor circulation.
Innovation Solution
A backrest design that supports the erector spinae muscles with a planar rigid or elastic body, broadening the width to the left and right, avoiding protrusions like shoulder blades and iliac crests, and positioning support between the iliac bones to maintain a straight spinal column alignment, distributing pressure uniformly and preventing buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a planar backrest is used to cover the entire back, then the backrest structure is simple, but the spinal column cannot be supported straightly due to anatomical protrusions
Solution Approach 1:
The backrest is divided into multiple functional zones: upper backrest portion for shoulder blade area, lower backrest portion for lumbar area, and side portions extending laterally. Each zone is positioned to support specific anatomical structures, transforming a single planar surface into segmented functional regions that address different parts of the back independently.
Solution Approach 2:
Different regions of the backrest have different widths and positions tailored to local anatomical requirements. The side portions extend laterally beyond the spinal column to support erector spinae muscles at specific locations, while the central portion supports the spinal column itself. This local customization ensures each area provides appropriate support without interfering with protruding structures.
2Area of stationary object
If the backrest width is increased to broaden support area, then pressure distribution improves, but contact with protruding structures like shoulder blades and iliac crests causes discomfort
Solution Approach 1:
The backrest has asymmetric width distribution: it is broader laterally at the upper and lower portions to support muscle groups, while being narrower at the central spinal region to avoid protruding structures. The side portions extend further left and right than the central portion, creating an asymmetric profile that maximizes support area while clearing anatomical obstacles.
Solution Approach 2:
The backrest surface is formed with curvature matching the natural contours of the back. The surface curves to accommodate the lumbar lordosis and follows the profile of erector spinae muscles, ensuring continuous contact with soft tissue surfaces while maintaining clearance from bony protrusions through shaped clearance zones.
3Reliability
If pressure is concentrated on the lumbar portion to support the spinal column, then spinal alignment improves, but circulation deteriorates due to reduced contact area
Solution Approach 1:
The support function is extended from a single central vertical line to a three-dimensional volume by adding lateral extensions. The backrest provides support not only in the mediolateral direction but also in the anteroposterior direction through curved surfaces, and vertically through distributed contact points along the spinal column and muscle groups, creating multi-dimensional support that distributes pressure volumetrically.
Data Source
AI summary
Provided with a backrest of a chair capable of reducing lumbago and fatigue by supporting a spinal column (2) straightly. A backrest (1) of a chair to support a back of erector spinae muscles (6, 6) with a planar rigid body in a region from both shoulder blades (3, 3) to both iliac bones (4, 4) for straightly supporting a spinal column (2) while avoiding an influence of both shoulder blades (3, 3) and both iliac bones (4a, 4a), wherein a width of the planar rigid body is broadened to right and left within a range where the planar rigid body is not in contact with a lower part of the ribs and both iliac crests (4a, 4a).