Chair, and lower-limb exercise system

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Solution Overview

Problem

Chronic low back pain, particularly non-specific low back pain, is often caused by mechanical stress and is difficult to treat effectively due to the need for prolonged exercise therapy and the challenge of maintaining motivation during long-term medical interventions.

Innovation Solution

A chair design with two coxal bone support portions that rock relative to a sacral bone support portion, enhancing the movability of the sacroiliac joint, thereby reducing mechanical stress on the lumbar region and promoting joint mobility through a lower-limb exercise system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional fixed sitting posture is maintained, then chair stability is ensured, but mechanical stress on lumbar region increases and low back pain occurs

Engineering Contradiction:
Improvemechanical stress on lumbar regionVSAvoidchair stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The chair transforms from a static fixed structure to a dynamic system where the seat can rock back and forth. The rocking mechanism allows the seat to move in response to user movement, creating a dynamic sitting experience that reduces mechanical stress on the lumbar region while maintaining stability through controlled motion ranges.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The chair is divided into separate functional components: a fixed base structure for stability and a movable rocking seat for stress reduction. This segmentation allows the stable base to remain stationary while the seat portion independently rocks to relieve lumbar pressure, resolving the contradiction between stability and stress reduction.

Inventive Principle:
Principle #1Segmentation

2Reliability

If exercise therapy is performed for several months, then low back pain is eliminated, but user motivation decreases due to long treatment duration

Engineering Contradiction:
Improvepain relief effectivenessVSAvoidtreatment duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The chair enables users to perform therapeutic exercise independently at home without requiring several months of hospital-based treatment. The rocking mechanism provides self-service functionality where the user's own body weight and movement drive the therapeutic effect, eliminating the need for prolonged supervised treatment and maintaining motivation through immediate, tangible results.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The chair design incorporates therapeutic functionality into the sitting experience itself, allowing users to begin pain relief immediately upon use rather than requiring months of preparatory exercise therapy. The rocking motion pre-establishes the therapeutic effect that would otherwise require prolonged treatment to achieve.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If sacroiliac joint movability is improved through rocking motion, then mechanical stress on lumbar region is reduced, but chair structure complexity increases

Engineering Contradiction:
Improvemechanical stress on lumbar regionVSAvoidchair structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The chair employs a simple rocking mechanism that allows the seat to dynamically adjust to user movement, improving sacroiliac joint movability and reducing lumbar stress without requiring complex active control systems. The dynamic motion is achieved through passive mechanical design rather than complex actuation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The chair changes the motion parameters of the seat from fixed to rocking, allowing controlled angular displacement that improves joint movability. This parameter change achieves therapeutic effect through simple geometric modification rather than complex mechanical systems.

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 chair effectively relieves low back pain by improving sacroiliac joint mobility, reducing muscle fatigue, and allowing for at-home exercise, thus addressing the challenges of maintaining motivation and effectiveness in conventional treatments.

Implementation Method 1

the two first support portions are configured to be able to rock in a pitch direction and a roll direction due to elastic deformation of the two elastic coupling portions

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4599904A1Chair, and lower-limb exercise system
Publication Date: 2025.08.13 TOYOTA JIDOSHA KK
  • EP4599904A1 patent drawingFigure 1
  • EP4599904A1 patent drawingFigure 2
  • EP4599904A1 patent drawingFigure 3

AI summary

A chair includes: two coxal bone support balloons that support two coxal bones respectively; and a sacral bone support balloon that supports one of a sacral bone and a coccygeal bone. The two coxal bone support balloons are configured to be able to rock relative to the sacral bone support balloon. In this configuration, the movability of a sacroiliac joint between the two coxal bones and the sacral bone is improved, and therefore, the mechanical stress on a lumbar region joint, on which a load increases in compensation for an insufficient movability of the sacroiliac joint, is curbed, so that a low back pain is relieved.