Ergonomic Desin Study Nov 2010

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H E N S S L E R U N D S C H U L T H E I S SP R O D U C T D E S I G N

Ergonomic Design Study

Table microscopes

Microscopy Business Group

Carl Zeiss

Excerpt from the study of Feb. 02, 2002


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Contents

1. Introduction

2. Problems in the current situation

2.1 Insufficient instrument height

2.2 Ergonomically awkward adaptation of the body posture when the

viewing height is too low

3. Ergonomically correct sitting position at the workstation

3.1 Body posture and sitting position

3.2 Anthropometrical distribution within a population group

3.3 Body height of the global population

3.4 Height comparison between relevant population groups

3.5 Adaptation of body height by vertical adjustment of chair and eyepieces

4. Proposals for the technical implementation in existing systems

4.1 Vertically adjustable base plate with hand rest4.2 Vertically adjustable tube with invariable viewing angle

5. Basis of the study and literature references


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1. Introduction

The present ergonomic design study deals with table microscopes and

their fatigue-free, functional and user-friendly operation.

Typical work situations have been examined and evaluated on the basis

of relevant ergonomic key data.

From the results and dimensions, solutions have been derived on which

future developments in the microscopy area can be based.

One specific focus of the study available here in excerpts

is the improvement of the situation of routine users who spend

several hours a day at a microscopy workstation.


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With an ergonomically correct sitting posture

at the table, viewing into the eyepiece is inconvenient

for the majority of users.

(The average body height of the population has been

taken as the standard)

Orientation heights in the

presentation:

95 percentile men

50 percentile men

50 percentile women

5 percentile women

General height distributionwithin a population group

2.1 Insufficient instrument heightinsufficient viewing height

standard

instrumentheight


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- Unfavorable support of lower arm on the

table plate

= aching pressure points and clumsy

operation of controls

- Awkward posture of back and

head

= tension of back and head

muscles

- wide arms position

= unfavorable operation of controls

- Adaptation to height via adjustable

eyepieces

= changed viewing angle after heightadaptation and unfavorable neck posture

in the upper height positions

2.2 Ergonomically awkward adaptation of the body posture

when the viewing height is too low


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The shown sitting position provides ideal conditions

for fatigue-free microscopy at a table microscope.

To avoid unnecessary strain to the neck and shoulder muscles,

the forward tilt of the head should be approx. 20 degrees.

An upright head posture would be ideal.

When the user looks into the eyepieces, his head is tilted

in accordance with the position of the pupil in his eye.

The height of the chair should be set in accordance with

personal requirements in such a way that the lower arms rest

horizontally on the table plate and the upper arms are relaxed.

Normally, the thighs are slightly below the table plate when

this posture is taken.

3.1 Body posture and sitting position

The tilt of the head is

approx. 20

Adaptation of sitting height

The seat slightly slopes

forward

Reference point: table surface

The lower arms rest horizonta

on the table edge

There is no tension in the uppe

arms

The upper part of thebody is as straight as

possible

The heads center of gravity

lies within the body balance

The back is straight


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3.2 Anthropometrical distribution within a sample population group

from Central and Eastern Europe

The left limit corresponds to theshortest heights of the analyzed

women

= only 5% are shorter

The right limit corresponds to thetallest heights of the analyzed men

= only 5% are taller

The center field marks the most

frequent heights

Presentation principle of the

following examinationsBasic height distribution within a

population group

Populationpercentage

Total

Men

Women

Population

percentage

Populationpe

rcentage

1500mm

1600mm

1700mm

1800mm

1900mm

1500mm

1600mm

1700mm

1800mm

1900mm

1500

mm

1600

mm

1700

mm

1800

mm

1900

mm


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Comparison of body heights and

proportions of 13 groups determined anthropometrically

to represent the global population.

3.3 Body height of the global population

worldwide tallest heights of all

recorded population groups

worldwide shortest heights of

all recorded population groups

North Asia

North India

Near East

West Africa

North Africa

Iberian Peninsula

Southern Europe

Central and Eastern Europ

Scandinavia

Latin America, Europid Negr

North America

Japan

South-East Asia


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- Scandinavia

- Central and Eastern Europe

- Japan

- South-East Asia

Each of the bars displayed is limited by the

heights of women on the left and those of menon the right.

The center field marks the most

frequent heights.

3.4 Height comparison between four

relevant population groups

Central and Eastern Eur

Scandinavia

Japan

South-East Asia


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As regards the viewing height of the

eyepieces, different body heights are mainly

compensated for by adapting the

sitting height. (Short persons might

require a footrest if the table height

cannot be adjusted)

Due to the ergonomically recommended body positioning,

i.e. with the lower arms positioned as horizontal as

possible, the eye position lies between 500 mm and

530 mm, even in cases of extreme differences in the

body height.

Body heights, based on the anthropometricpattern in Central and Eastern Europe.

1867 95 percentile men

1753 50 percentile men

1652 50 percentile women

1567 5 percentile women

3.5 Adaptation to body height by vertical adjustment

of chair and eyepieces

Area of optimum instrument

height between 500 mm

and 530 mm

Adaptation of

sitting height

Reference pointable surface


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4. Proposals for technical implementation

4.1 Vertically adjustable base plate with hand rest

Optimum height rangeA vertically adjustable base plate with hand rest

provides settings within the range of optimum

viewing heights

Support with

hand rest


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The optimum instrument height is achieved

with a vertically adjustable tube permitting

an optimum sitting position.

4.2 Vertically adjustable tube with

invariable viewing angle

4. Proposals for technical implementation

Optimum height area

Vertically adjustable tube with

invariable angle


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The study is based on current ergonomic key data and empiric

examination results obtained on the object.

The results were reviewed on a group of 15 persons.

5. Basis of the study and literature references

The measure of man and woman 1993 Alvin R Tilley, Henry Dreyfuss Assosiation, New York

Rumlich-ergonomische Gestaltung 1990 Bundesanstalt fr Arbeitsschutz (Fb 632)

Ergonomische Arbeitsmittelgestaltung 3 1979 Bundesanstalt fr Arbeitsschutz (Forschungsbericht Nr. 198)

Reibung zwischen Hand und Griff 1979 Bundesanstalt fr Arbeitsschutz (Forschungsbericht Nr. 213)

Internationaler

anthropometrischer Datenatlas 1989 Bundesanstalt fr Arbeitsschutz (Fb 587)

Ergonomic Design for People at Work

Volume 1 1983 Eastman Kodak Com

Grundlagen der Broeinrichtung 2000 Roger Schlimm

Ergonomie 1996 BIA-Report HVBG

Ergonomic Desin Study Nov 2010

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