TRIZ 2009

The Fifth TRIZ Symposium in Japan

Concept Design of a Child-Seatby TRIZ Style
Problem Identification

Masao Ishihama & Minami Hamada
Automotive Technology Center
Kanagawa Institute of Technology

1. Background of the Study Safety of child-seats for motor vehicles is amatter of national concern.
 Only a few child-seat brands have passed safety
regulations set by Japanese government.
 Unsatisfactory practical usability is frequentlyreported.
***********************
 However, problems to solve were not so clear
for the authors to start designing.

2. Defining Our DesignProblems
 Problem Formulation of TRIZ style wasused.
 Expected functions and unexpected or
harmful functions of child-seats werelisted.
 Functions are investigated separatelyaccording to child-seat using scenes andstakeholders’ interests.

Scenes analyzed
 Installation into a passenger compartment
 Loading and unloading of a child Vehicle acceleration and deceleration
 Riding over rough road surfaces
 Eating and drinking
 Playing on the seat Collision

Stakeholders considered Child
 Parent who care the child Driver and the other passengers
 Producer of the child-seat Producer of the vehicle
 Government officer

Installation into a passengercompartment
 This work is not frequent.
 Mounting brackets for fitting child-seats

became popular in recently developed cars.
 Identified as a less serious problem

Loading/unloading of a child Hard job for parents.
 Side guards block smooth loading &unloading of a child.

Vehicle acceleration anddeceleration
 Highly frequent situation.
 Need to protect the child from neck injury.
 Strong influence on ride comfort.
 High seat-back and tight seat strap areconventional unsatisfactory solutions.

Turning corners
 Highly frequent situation.
 Need to protect the child from neck injury.
 Strong influence on ride comfort.
 Side-guard is a conventional unsatisfactorysolution.

Riding over rough road surfaces
 Highly frequent situation.
 Need to protect the child from neck injury

and motion sickness.
 Strong influence on ride comfort.
 Direct control on vibration insulation anddamping is possible by child-seat design.

Eating and drinking
 Help by parent is necessary sometimes.
 Parent’s service is quite awkward due totheir restricted body movement.
 Need free torso movement of the child, but
restricted by seat straps.

Collision Vital function of protecting the child andother passengers.
 Restraining the child’s body is necessary
avoiding head collision against front seatback.
 Front, side and rear impact need to beconsidered.

Defined problems to solve
 Easing the parent’s labor inloading/unloading their child.
 Reducing vibration of the child.
 Restraining the child in collision while giving
him/her free movement in normal
conditions.

3. Resource Analysis
 Around the child seat:* Wider space than those for adultpassengers.
* Information on CAN (LAN on a car) thattells potential collision beforehand.

4. Defining Contradictions
 Side-guard function: Between the two

movement of the child, such as easyloading vs. constraining lateral movement.
 Between the two functions: Vibration
isolation (supporting flexibly) on roughroads and restraining tightly at collision.
 Free movement for eating/drinking andtight restraint at collision.

5. Inventive Principles used andConceptual Design Embodied
 “Segmentation”

Separating seat and support.

 “Dynamicity”

90 degree horizontal seat “Spheroidality,Counter-weight& Self-service.

 “Universality”

turn for loading.
Swinging motion forvibration absorption andchild attitude control

Realize the above function

by spherical hollow surface
for a seat pad..

6. Sketch of the Design -1

6. Sketch of the Design - 2

Movement in loading/unloading Move to other dimensions
 Balancing

 A seesaw and snap action mechanism

automatically pushes up or pulls down theside guards by the child’s weight.
Child’s weightOffOnVibration control action
 Dynamicity
 Mechanical vibration
 Division

Vibration isolation by setting
the natural frequency low
Lateral vehicle vibration

Movement in collision
 Moving to a newdimension.

 Receiving G at collisionby the seat pad rather
than seat belts.

 Prior action.
 Utilizing deceleration

signal from CAN andtightening the belts.

Conclusions
 Conceptual design of a child seat was createdthat solves vital problems of conventional
products.
 The TRIZ function and attribute analysis identified
successfully the problems to solve that were hardby conventional methods.
 Resource analysis found the key factors of childseat design.
 These tasks were easily achieved by a graduate
student who studied TRIZ just a few weeks.