CH- 6 ERGONOMICS part-1

8/7/2019 CH- 6 ERGONOMICS part-1

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CHCH-- 66

ERGONOMICSERGONOMICS


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IntroductionIntroduction

The word 'Ergonomics' owes its origin toThe word 'Ergonomics' owes its origin totwo Greek words; ERGOS meaning Worktwo Greek words; ERGOS meaning Workand NOMOS meaning Study.and NOMOS meaning Study.

The ILO definition is:The ILO definition is:-- Ergonomics is theErgonomics is theapplication of the human biological sciencesapplication of the human biological sciencesin conjunction with engineering sciences toin conjunction with engineering sciences tothe worker and his working environment, sothe worker and his working environment, soas to obtain maximum satisfaction for theas to obtain maximum satisfaction for theworker and at the same time enhanceworker and at the same time enhance

productivity.productivity. Thus, the objective of Ergonomics is twoThus, the objective of Ergonomics is two

fold:fold:

(a) Worker Satisfaction(a) Worker Satisfaction

(b) Enhanced productivity.(b) Enhanced productivity.


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IntroductionIntroduction Ergonomics achieves the above by the study ofErgonomics achieves the above by the study of

conditions in which people work most effectivelyconditions in which people work most effectivelyand comfortably with machines. It aims atand comfortably with machines. It aims atmaking the working environment synergtical tomaking the working environment synergtical tothe human activities and thus improving overallthe human activities and thus improving overalllabor productivity.labor productivity.

Ergonomics covers a very wide area startingErgonomics covers a very wide area startingfrom initial conceptual design stage to ultimatefrom initial conceptual design stage to ultimateproduction facilities. It helps create betterproduction facilities. It helps create betterworking conditions by suggesting:working conditions by suggesting:

(a) The best way of using human body.(a) The best way of using human body.(b) The best way of arranging the workplace.(b) The best way of arranging the workplace.

(c) The best design of tools and equipment.(c) The best design of tools and equipment.


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Use of ErgonomicsUse of Ergonomics Today the market has changed from aToday the market has changed from a

seller's market to buyer's market; andseller's market to buyer's market; andproductivity has become a buzzword.productivity has become a buzzword.

The Principles of Ergonomics help inThe Principles of Ergonomics help inimproving the labor productivity giving theimproving the labor productivity giving the

competitive edge to the organization.competitive edge to the organization. The ageThe age--old concept of finding a worker to doold concept of finding a worker to do

a job is no longer valid.a job is no longer valid.

The modern concept is to design the job toThe modern concept is to design the job to

suit the worker.suit the worker. Job satisfaction & Job interest are the twoJob satisfaction & Job interest are the two

vital ingredients to obtain better laborvital ingredients to obtain better laborproductivity.productivity.


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Use of ErgonomicsUse of Ergonomics

It is an established fact that uncongenial workingIt is an established fact that uncongenial workingconditions affect productivity adversely.conditions affect productivity adversely.

A worker's interest in his job depends to a greatA worker's interest in his job depends to a great

extent on how comfortable the workplace is.extent on how comfortable the workplace is.

Ergonomics not only 'helps in creating a betterErgonomics not only 'helps in creating a betterworking environment, it also motivates workersworking environment, it also motivates workers

as human comfort is given the priority whileas human comfort is given the priority while

applying this principle.applying this principle.


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Ergonomics and Workplace DesignErgonomics and Workplace Design

Shalini was waiting for SachinShalini was waiting for Sachin ,, the interiorthe interior

decorator. Two days earlier, he had given her adecorator. Two days earlier, he had given her ainterior design catalogue. Shalini went through it,interior design catalogue. Shalini went through it,

but none of the designs appealed to her. Shebut none of the designs appealed to her. She

called Sachin to discuss the design.called Sachin to discuss the design.

You have seen some of my best work, SachinYou have seen some of my best work, Sachin

started, but it seems you did not like a singlestarted, but it seems you did not like a single

design!design!

Well the designs are excellent, but I didnt findWell the designs are excellent, but I didnt find

anyone suitable for my kitchen. It seems all ofanyone suitable for my kitchen. It seems all of

them are somewhat Westernized," repliedthem are somewhat Westernized," replied

Shalini.Shalini.


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What do you mean by Westernized ?What do you mean by Westernized ?Look, I am a short lady of five feet and two inches.Look, I am a short lady of five feet and two inches.

The kitchen platforms that your designs show areThe kitchen platforms that your designs show arefor American housewives who are much taller thanfor American housewives who are much taller thanus. With this height, I will have to put a stool underus. With this height, I will have to put a stool undermy feet", replied Shalini.my feet", replied Shalini.

Then should I reduce height to say two feetThen should I reduce height to say two feetSachin asked.Sachin asked.

No, then I will have to bend every time and withinNo, then I will have to bend every time and within

a year I will become a patient of spondilietes. Ia year I will become a patient of spondilietes. Ithink a height of two feet and eight or nine inchesthink a height of two feet and eight or nine inchesshould suit me.should suit me.

Well do you have any other suggestion?"Well do you have any other suggestion?"


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Yes I do. replied Shalini. As I am a left handedYes I do. replied Shalini. As I am a left handedperson, I want the wash basin on the left side ofperson, I want the wash basin on the left side of

the platform. Also) I don)t want to keep spoons,the platform. Also) I don)t want to keep spoons,

knifes, forks etc. in one drawer because it takesknifes, forks etc. in one drawer because it takes

time to take them out when they are neededtime to take them out when they are neededurgently.urgently.

O.k. I will give you a fixture or stand where youO.k. I will give you a fixture or stand where you

can keep these things. And the stand will becan keep these things. And the stand will be

kept so that your hand can reach it easily i.e. akept so that your hand can reach it easily i.e. aplace for everything and everything in place,place for everything and everything in place,

said Sachin.said Sachin.

There must be proper light on the table but theThere must be proper light on the table but the

glare should not reduce the visibility. The kitchenglare should not reduce the visibility. The kitchen


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Then IThen I will put the tube lights on right or leftwill put the tube lights on right or leftside and not in the front or back side. Andside and not in the front or back side. And

provide a exhaust fan for ventilation. Do youprovide a exhaust fan for ventilation. Do you

want any particular design for the platform,want any particular design for the platform,

asked Sachin.asked Sachin.

Yes, I want the platform to slope towards theYes, I want the platform to slope towards the

basin so that the water will not accumulate onbasin so that the water will not accumulate on

it and Iit and I can keep it clean and dry it withoutcan keep it clean and dry it withoutmuch effort.much effort.

Sachin carefully noted down all theSachin carefully noted down all the

suggestions. Anything else madam he askedsuggestions. Anything else madam he asked

winding up.winding up.


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Nothing special but remember that kitchen is myNothing special but remember that kitchen is my

workplace and it must be designed to suit me soworkplace and it must be designed to suit me so

thatthat11can work comfortably, Shalini concludedcan work comfortably, Shalini concluded

their conversation.their conversation.


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Ergonomics & Product or EquipmentErgonomics & Product or Equipment

DesignDesign My new client Shalini was telling me to designMy new client Shalini was telling me to design

her kitchen with emphasis on the comfort of use.her kitchen with emphasis on the comfort of use.

She mentioned that her kitchen was herShe mentioned that her kitchen was her

workplace and Iworkplace and I was reminded of the principleswas reminded of the principles

of Ergonomics that you were talking about theof Ergonomics that you were talking about the

other day. Sachin was talking to his friendother day. Sachin was talking to his friend

Parag a management student.Parag a management student.

Yes housewives seem to have this knack ofYes housewives seem to have this knack of

using our management principles in theirusing our management principles in theireveryday work and they call it common sense.everyday work and they call it common sense.

By the way we also use the Principles ofBy the way we also use the Principles of

Ergonomics for product or equipment design.Ergonomics for product or equipment design.

replied Parag.replied Parag.


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Product or Equipment DesignProduct or Equipment Design

The same principles are used in designing aThe same principles are used in designing aproduct or a tool giving priority to human comfort.product or a tool giving priority to human comfort.We try to synchronize the functional requirementsWe try to synchronize the functional requirementsof a product with that of the human capacity saidof a product with that of the human capacity saidParag.Parag.

Please explain with an example. urged Sachin.Please explain with an example. urged Sachin. O.K.O.K. Take the case of the car itself. Now SteeringTake the case of the car itself. Now Steering

is a continuous operation while you are driving andis a continuous operation while you are driving andit demands a certain amount of skill. Henceit demands a certain amount of skill. Hencesteering is a hand operation.steering is a hand operation.

Now other operations like using the brake or theNow other operations like using the brake or theclutch are intermittent and demand a certainclutch are intermittent and demand a certainamountamount--of force which can only be applied with theof force which can only be applied with thefeet and hence these are foot operated. Also notefeet and hence these are foot operated. Also notethat the brake and the clutch are positioned in athat the brake and the clutch are positioned in a

such a way that the foot gets a leverage whilesuch a way that the foot gets a leverage while


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This sounds interesting exclaimed Sachin, areThis sounds interesting exclaimed Sachin, arethere any other aspects of ergonomics used inthere any other aspects of ergonomics used indesigning the car?designing the car?

Yes. Look at the driving seat. It is made adjustableYes. Look at the driving seat. It is made adjustableso that people of different heights can driveso that people of different heights can drivecomfortably. Also the design and position of thecomfortably. Also the design and position of theseat enables the driver to hold the steering wheelseat enables the driver to hold the steering wheeland use his feet for brake and clutch veryand use his feet for brake and clutch verycomfortably. You will also observe that the horn iscomfortably. You will also observe that the horn is

fixed on the steering wheel so that the driverfixed on the steering wheel so that the driverdoesnt have to make much of a hand movementdoesnt have to make much of a hand movementto horn.to horn.

So, you cannot change the design of the product.So, you cannot change the design of the product.Sachin was worried.Sachin was worried.


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Nothing stops you from innovating andNothing stops you from innovating and

improving. replied Parag. But all your productimproving. replied Parag. But all your product

innovations must be backed by properinnovations must be backed by proper

Ergonomic study; or else your customers willErgonomic study; or else your customers willreject your product calling it inconvenient.reject your product calling it inconvenient.

Sachin nodded his head in agreement.Sachin nodded his head in agreement.


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Factors of ConsiderationFactors of Consideration To produce a workplace that will give theTo produce a workplace that will give the

minimum amount of strain to the worker,minimum amount of strain to the worker,Ergonomics takes into account the followingErgonomics takes into account the followingthree factors.three factors.

Anthropometric DataAnthropometric Data

Human Activity AnalysisHuman Activity Analysis Primary Motion StudyPrimary Motion Study

11.6.1 Anthropometric Data11.6.1 Anthropometric Data

Anthropometry is the study of measurement ofAnthropometry is the study of measurement ofphysical features of human beings.physical features of human beings. ItIt alsoalsostudies the strength of various muscles andstudies the strength of various muscles andranges of body movement. These features andranges of body movement. These features andfunctions are subject to variation according tofunctions are subject to variation according toage, gender, race etc. Data on these features isage, gender, race etc. Data on these features is

called Anthropometric data.called Anthropometric data.


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Factors of ConsiderationFactors of Consideration

The data on human body dimensions are of twoThe data on human body dimensions are of two

types:types:

(a) Structural Dimensions(a) Structural Dimensions

These are the body dimensions of a person inThese are the body dimensions of a person in

static condition. There are two static conditions,static condition. There are two static conditions,

namely sitting and standing. The example of anamely sitting and standing. The example of a

structural dimension of 'standing' is height of astructural dimension of 'standing' is height of a

person when he stands in the erect position.person when he stands in the erect position.


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(b) Functional Dimensions(b) Functional Dimensions These are the body dimensions of aThese are the body dimensions of a

person while in motion. These are moreperson while in motion. These are more

important than the structural dimensionsimportant than the structural dimensionsas most of the working conditions areas most of the working conditions are

dynamic in nature. One such example ofdynamic in nature. One such example of

functional dimension is an 'overheadfunctional dimension is an 'overhead

reach' . Overhead reach is defined as thereach' . Overhead reach is defined as the

reach of an erect standing person when hereach of an erect standing person when he

raises the hand straight .raises the hand straight .


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2 Human Activity Analysis2 Human Activity Analysis

In order to reduce the strain c~1Used by the work requirement, theIn order to reduce the strain c~1Used by the work requirement, the

desired human activities are analyzed. The activities are analyzeddesired human activities are analyzed. The activities are analyzed

on the following basis:on the following basis:

(a) Movements:(a) Movements:

This analyzes movement of different body parts.This analyzes movement of different body parts.

(b) Human Strength and Endurance:(b) Human Strength and Endurance:

Appropriate activities are assigned to appropriate muscle groups toAppropriate activities are assigned to appropriate muscle groups to

reduce the strain,reduce the strain,

(c) Speed and Accuracy:(c) Speed and Accuracy:

Different limb movements are capable of giving different speed andDifferent limb movements are capable of giving different speed and

accuracyaccuracy

e.g. In a manual sewing machine, the pedal is operated by the feet,e.g. In a manual sewing machine, the pedal is operated by the feet,

which provides the force, to produce the necessary speed; whereaswhich provides the force, to produce the necessary speed; whereas

the cloth is held by the hands as accuracy is then better achieved.the cloth is held by the hands as accuracy is then better achieved.


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Principles of Motion EconomyPrinciples of Motion Economy These are a set of rules developed by Frank B.These are a set of rules developed by Frank B.

Gilbreth. They achieve economy in movementsGilbreth. They achieve economy in movementsand reduce fatigue. They also help in developingand reduce fatigue. They also help in developing

improved methods of working.improved methods of working.

These principles are divided under three heads:These principles are divided under three heads:

(a) Principles Concerning the use of human body.(a) Principles Concerning the use of human body.

(b) Principles concerning the design of workplace.(b) Principles concerning the design of workplace.

(c) Principles concerning the design of tools and(c) Principles concerning the design of tools andequipment.equipment.


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Principles concerning use ofPrinciples concerning use of

Human BodyHuman Body

(1)(1) The two hands should begin as well asThe two hands should begin as well as

complete their motions at the same time.complete their motions at the same time.

(2) The two hands should not be idle at the same(2) The two hands should not be idle at the same

time except during the rest period.time except during the rest period.

(3) Motion of the arms should be made in opposite(3) Motion of the arms should be made in opposite

and symmetrical direction & should be madeand symmetrical direction & should be made

simultaneously.simultaneously.

(4) Ballistic movements are faster and more(4) Ballistic movements are faster and more

accurate than restricted or controlledaccurate than restricted or controlled

movements.movements.


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Principles concerning use ofPrinciples concerning use of

Human BodyHuman Body(5) Work should be structured to permit easy(5) Work should be structured to permit easyand natural rhythm wherever possible.and natural rhythm wherever possible.

(6) Eye fixation should be as little and as(6) Eye fixation should be as little and asclose together as possible.close together as possible.


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Principles concerning design ofPrinciples concerning design of

workplaceworkplace

1.1. There should be a definite & fixed place for allThere should be a definite & fixed place for alltools & materials.tools & materials.

2.2. Tools, materials & controls should be locatedTools, materials & controls should be locatedclose to the point of use.close to the point of use.

3.3. Gravity feed bins & containers should be usedGravity feed bins & containers should be usedto deliver material close to the point of use.to deliver material close to the point of use.

4.4. Drop deliveries should be used whereverDrop deliveries should be used whereverpossible.possible.

5.5. Materials & tools should be located so as permitMaterials & tools should be located so as permitthe best sequence of motion.the best sequence of motion.

6.6.Provisions should be made for adequateProvisions should be made for adequateconditions for seeing.conditions for seeing.


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Principles concerning design ofPrinciples concerning design of

workplaceworkplace

7. Good illumination is the first requirement7. Good illumination is the first requirementfor satisfactory visual perception.for satisfactory visual perception.

8. The height of workplace & the chair8. The height of workplace & the chair

should be so arranged that it suitsshould be so arranged that it suitsmaximum number of workmen.maximum number of workmen.

9. A chair of the type & height to permit good9. A chair of the type & height to permit goodposture, should be provided for everyposture, should be provided for every

worker.worker.


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Principles Concerning DesignPrinciples Concerning Design

Of Tools & Equipment:Of Tools & Equipment:

1.1. The hand should be relieved of all work that can beThe hand should be relieved of all work that can bedone more advantageously by jigs or fixtures.done more advantageously by jigs or fixtures.

2.2. Two or more tools should be combined wheneverTwo or more tools should be combined whenever

possible.possible.3.3. Tools and materials should be preTools and materials should be pre--positioned wheneverpositioned whenever

possible.possible.

4.4. Where each finger performs some specific functionWhere each finger performs some specific functionsuch as in typewriting, the load should be distributed insuch as in typewriting, the load should be distributed inaccordance with the inherent capacities of the fingers.accordance with the inherent capacities of the fingers.

5.5. Levers, crossbars & handLevers, crossbars & hand--wheels should be located inwheels should be located insuch positions that the operator can manipulate themsuch positions that the operator can manipulate themwith the least change in body position & with thewith the least change in body position & with thegreatest mechanical advantage.greatest mechanical advantage.


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CH- 6 ERGONOMICS part-1

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