Page 63 - Mechatronics for Safety, Security and Dependability in a New Era

Ch11-I044963.fm Page 47 Tuesday, August 1, 2006 8:51 PM
Tuesday, August
Page 47
8:51PM
1, 2006
Ch11-I044963.fm
47
47
DEVELOPMENT OF A NON-POWERED LIFT
FOR WHEELCHAIR USERS
- MECHANISM TO TRANSMIT ROTATION OF WHEELS
BY MANY ROLLERS -
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2
Y. Kobayashi , H. Seki', Y. Kamiya , M. Hikizu , M. Maekawa ,
Y. Chaya 3 and Y. Kurahashi 3
1
Department of Mechanical Systems Engineering, Kanazawa University,
Kakuma, Kanazawa, 920-1192, Japan
2
Industrial Research Institute of Ishikawa,
2-1 Kuratsuki, Kanazawa, 920-8203, Japan
' Fujiseisakusho Co., Ltd.,
Ha 195 Akai, Nomi, 920-0101, Japan

ABSTRACT

Wheelchair users need lifts to climb up / down steps at entrances with small spaces. Lifts driven by
motors or hydraulic equipments are large and expensive. They also need switches to start / stop
actuators. The aim of our study is to develop a compact and non-powered lift for wheelchair users. We
have already made a lift driven by wheels of a wheelchair on it, however, it has some problems.
Because wheelchair direction was fixed, a user must enter the lift backward in case of ascent.
Complicated mechanism must be equipped so that small front casters can pass through the lift stage
and large rear wheels can drive the lift. Therefore, a new non-powered lift using many rollers is
proposed to improve these problems.

KEYWORDS
Support system, Power assist, Lift, Wheelchair, Mechanism, Welfare tools

1. INTRODUCTION

In Japan, private houses usually have doorsteps at entrances. It is difficult for wheelchair users to
climb up / down such steps without attendants. Tf the height of a step is less than 150 mm, manual
wheelchair users can go it over by lifting front casters [1]. However, it requires a user's skill.
Generally, the height of doorsteps at the entrances are from 200 mm to 500 mm. One solution is to
place a slope, but it needs so much place for a wheelchair user to climb up easily (The slope should be
less than 10 degrees) [2]. Another solution is to use the lift which moves vertically as shown in Figure
1. Since most lifts are driven by electrical motors or hydraulic actuators, it makes the lifts large, heavy
and expensive. It asks users or attendants for switching operation to start / stop the lifts. Entrances