Transcript 1 - Transed 2012

The relationship between physical
workload and the position of tipping lever
of wheelchair while accompanied helper
lift up and down wheelchair front
Masaki Tauchi PhD, Kazuya Kuro-oka,
Takabun Nakamura PhD
Okayama Prefectural University, Japan
INTRODUCTION
Because of ‘Aged Society,’ the use of manual
wheelchairs for physically disabled is rapidly
increasing. Many of the elderly persons who use
wheelchairs are not able to maneuver freely by
themselves but need assistance of care workers.
One of the major problems when they encounter
in the mobile environment in the town is to clear
differences in heights on floor or road surface.
For this problem, tipping levers are equipped in
the rear of the wheelchair to lift up the front of
wheelchair. But the shape and position may not be
appropriate for the assistance by less powerful
persons.
The shape and the position of typical
tipping lever
PURPOSE
The tipping lever of manual wheelchair to lift up
and down the casters is not always easy to use
because of the present shape and/or position.
To find out appropriate position of the tipping
lever, we investigated the relationship between
the power needed to lift up and down casters and
positions of the tipping lever in this study.
For this purpose, an introspection of the effort
on upper and lower limb and load on lumber area
when the subjects lift up the front of wheelchair
at the various tipping lever position was measured.
METHODS
SUBJECTS
Eleven subjects having certain skill for wheelchair
assistance participated. Four of them were males and
7 were women, mean age 27.6 +/- 3.8yrs, body weight
57.8 +/- 10.9kg and height 165.8 +/- 10.2cm
SETTING OF EXPERIMENTAL TIPPING LEVER
On both sides of the tip of the
tipping levers, the experimental
tipping lever holders aligned to
the perpendicular to the
direction of travel were
attached.
THE SHAPE OF TIPPING LEVER
HOLDER (Large)
The tipping lever holders, Large, were
made allow to search wider range in the
lower posterior part of the wheelchair In
total 17 positions were examined.
Distance from wheel axis (cm)
23.0
17.5
15.0
The tip of TPL
position of control
12.5
10.0
7.5
floor
Height from floor (cm)
Wheel axis
15.0
11.0
19.0
THE LOAD ON THE WHEELCHAIR
The concrete slab was used as a dummy
load of wheelchair user. The weight
placed on the seat was as much as 70%
of the weight that the individual subjects
can manage to lift up the front.
EXPERIMENTAL PROCEDURE
10㎝
① Lift up the front of the loaded
wheelchair and step forward to put caster
on the of 10cm high platform slowly
② Ask ‘how heavy it was’ for the work
③ Lift up front again, then land on floor
stepping backward slowly
④ Ask ‘how heavy it was’ for the work
10㎝
Result 1 The spatial distribution of the average effort of
upper and lower limbs and load on lumber area
Distance from wheel axis (cm)
15.0
11.0
19.0
23.0
Effort
or load
Height from floor (cm)
17.5
Large
15.0
12.5
10.0
7.5
control
Small
THE SHAPE OF TIPPING LEVER HOLDER (S)
The tipping lever holders S allow to take 14 different
positions in total including two control positions at
foremost and rearmost locations. The pits for four
different heights and three distances were installed on the
holder.
Distance from wheel axis (cm)
27.5
Wheel axis
20.0
17.5
15.0
Control
position 2
The tip of TPL,
control position 1
The shape of
TPL holder used
in Experiment 1
12.5
13.75 15.0 17.5
floor
Height from floor (cm)
22.5
EVALUATION
1) Effort on lower limb and upper limb
Need very small power (1pt)
~Need large power (5pts)
The effort of position 1 (the tip of tipping levers) was set at 5
points and the position 2 at 1pt. The subjects answered their
effort by taking numbers at intervals of 0.5.
2) Load on lumber area
Feel very small load( 1pt)
~ Feel large load (5pts)
Measurement was the same as lower and upper limbs
Result 2
Large
Effect of distance from wheel axis to
physical effort on lower limb
5
5.00
Position 1
**
**
**
** p<0.001
Physical effort
4.00
3
3.00
17.5
Small
2.00
15.0
13.75
12.5
1
15.0 17.5 20.0 22.5
1.00
15.0
15.0
17.5
17.5
20.0
20.0
Distance from wheel axis
22.5
22.5 (cm)
Large
Result 3
Effect of height from floor to physical
effort on lower limb
Distance from wheel axis
17.5 cm
5
5.00
Distance from wheel axis
20.0 cm
5.00
Distance from wheel axis
22.5 cm
5.00
Small
Physical effort/load
17.5
4.00
4.00
4.00
15.0
13.75
12.5
15.0 17.5 20.0 22.5
3
3.00
3.00
17.5
17.5
2.00
2.00
15.0
13.75
12.5
11.0012.00
3.00
15.0 17.5 20.0 22.5
15.0 17.5 20.0 22.5
13.00 14.00 15.00 16.00 17.00 18.00
13.0
15.0 17.0
2.00
15.0
13.75
12.5
1.00
12.00 13.00 14.00 15.00 16.00 17.00 18.00
13.0
15.0 17.0
1.00
12.00 13.00 14.00 15.00 16.00 17.00 18.00
Height from floor (cm)
13.0
15.0 17.0
17.5
Small
Large
Large
15.0 17.5 20.0 22.5
Upper limb
5
3
3.00
2.00
3
3.0
1
1.0
15.0
15.0
17.5
17.5
20.0
20.0
22.5
22.5
(cm)
22.5
22.5
(cm)
Lumber
5
5.0
3
3.0
2.0
1.00
15.0
15.0
17.5
17.5
20.0
20.0
22.5
22.5
Distance from wheel axis
Small
Small
4.0
4.0
Physical load
Physical effort
4.00
1
Lower limb
5
5.0
2.0
15.0
13.75
12.5
5.00
Large
Comparison of physical effort
on upper and lower limb and
load on lumbar area to the
distance from wheel axis
Physical effort
Result 4
1
1.0
15.0
15.0
17.5
17.5
20.0
20.0
Distance from wheel axis
Result 5
Mapping of total average physical
effort and load of tipping lever
Distance from wheel axis (cm)
Height from floor (cm)
15.0
17.5
17.5
20.0
22.5
Large
15.0
Position 1
13.8
12.5
Small
Total average physical effort and load: mean value of physical
effort on upper and lower limbs and load on lumber
SUMMARY
•
The amounts of effort of subject’s lower and upper limbs and
physical load on lumber area decreased linearly toward lower
distal direction from the present tipping lever position.
• The effort and the load decreased when the height of the
tipping lever decreased, though the relationship was not
linear.
• The effort and the load were almost the same for both for
both lifting up and lifting down wheelchair front.
• By searching the appropriate space for tipping levers behind
wheelchair, it was found that the area around 12.5cm height
and 22.5cm distance from the axis of rear wheel fulfill the
purposes.
CONCLUSION
• By elongating and lowering the tipping levers
of the manual wheelchair certain amounts, to
lift up or down the casters become much
easier for assistance with low physical
strength persons.
Thank you for your attention
8. 結 論
・現状のティッピングレバー位置を、やや低く、水平位
置を介助者側により近づけることで、車いす前輪上
げ動作時における介助者の身体的負荷を軽減するこ
とが可能であることが分った。
・実用化には、ティッピングレバーの踏む部分の形状
に関する検討が必要である。
5.力学モデル
ティッピングレバーを鉛直線からθの角度で踏むと仮定する
M：回転モーメント、F：ティッピングレバーを踏む力
M = F・L・sin(θ +θ1）
－(1)
(1)式を展開し、Fについて整理する
F = M /（L2・sinθ + L1・cosθ） －(2)
Stevensの式に従い、力の感覚量で表す
H
J：力の大きさ感覚
J = k・FP k：定数、P：重さの場合は1.5
J = k・（M/（L2・sinθ + L1・cosθ） P
K=k・MP = 定数とし、L2をhで表し整理する
J = K・（（H－h）・sinθ + L1・cosθ）－P
= K・（（27.7－h）・sinθ + L1・cosθ）－1.5
車軸
L・sin(θ+θ1)
O
θ
θ1
L
L2
θ
TL
A
L1
h
床面
F
B
4-4.結果 ティッピングレバー位置と負荷*の分布
＊負荷量は下肢・上肢・腰それぞれの負荷の平均とした
負荷量
後輪軸からの水平距離（㎝）
床面からの高さ（㎝）
15.0
17.5
20.0
22.5
大
17.5
15.0
13.8
12.5
小
コントロール
非表示部分
6.負荷のモデルによる理論値
（B）床面からの高さと足への負荷の関係の
（A）水平位置と足への負荷の関係の
0.015
0.015
シミュレーション
シミュレーション
床面からの高さ (cm)
17.5
水平距離（cm）
17.5
20
22.5
0.01
13.8
12.5
力の感覚
力の感覚
15.0
0.01
0.005
0.005
15
17.5
20
22.5
後輪軸からの水平位置（cm）
12
14
16
床面からの高さ（cm）
18
Distance from wh
Height from floo
Physical load on
Physical load on
Physical load on