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Ch16-I044963.fm Page 73 Tuesday, August 1, 2006 9:08 PM
1, 2006
Tuesday, August
Page 73
Ch16-I044963.fm
9:08 PM
73 73
DEVELOPMENT OF MEASURING DEVICE
FOR LOWER LEG SWELLING
DURING STANDING WORK TASKS

T.Kawano and T.Mizuno
Department of Industrial and Systems Engineering, Setsunan University,
Neyagawa, Osaka 572-8508, JAPAN

ABSTRACT
In this study a measuring device called as SWELL (Sensoring Wire for Edema of Lower Leg) has
been developed in order to measure the lower leg swelling of the worker during the standing work
tasks. The device consists of a flexible wire, a coil spring, and a flat spring with a strain gauge. The
wire is wound around the lower leg with proper tension and the strain of the flat spring produces when
the leg swelling develops. The characteristics of the device, such as linearity, hysteresis, drift, and
thermal behavior, are demonstrated. Experiments were carried out to measure the swelling of the
lower leg for thirteen subjects. The results showed that SWELL was continuously able to measure the
leg swelling defined as the increase of the circumference length of the leg, the magnitudes of the
swelling increased almost linearly, and the measured average magnitudes were 3.0mm after standing
for 30 minutes. In addition, a strong correlation was shown between the swelling magnitude estimated
by digital camera method and the one measured with SWELL.

KEYWORDS

Lower Leg Swelling, Measuring Device, Strain Gauge, Standing Work, Human Directed
Manufacturing System

T. INTRODUCTION
The assembly lines and cell production system consist predominantly of workers' standing work tasks.
However, standing works often cause leg swelling and fatigue. Furthermore long-term leg swelling
increases the risk of developing pathological reactions such as varicose vein, thrombosis and
pulmonary embolism[l]. In order to decrease such fatigue and risks the workplace so as to reduce the
leg swelling should be designed in the standing work tasks. However, the adequate measuring device
for the leg swelling has not been around in actual workplaces. In order to evaluate the swelling such
factors are considered as lower-limb skin temperature[2], venous pressure[3], lymph flow[4], tissue
fluid pressure [5], ultrasound and venography[6], and bioelectrical impedance[7]. However, almost
previous studies have just used a tape measure to measure the magnitude of the swelling itself. The
measurements with the tape measure vary widely depending on the examiners. The measurement of