1-ANNEX%20frequency

8/7/2019 1-ANNEX%20frequency

1/10

Colombini D, Occhipinti E, Fanti M. epm Research Unit -Milan

1

AANNNNEEXX 11

FFrreeqquueenncc yy aanndd ii ddeenn tt ii ffii cc aa tt ii oonn oo ff tt ee cc hhnn ii cc aa ll aacc tt ii oonn

Characterization implies that any repetitive task for the upper limbs should be submitted to an analysis ifit requires carrying out consecutively, for at least 1-2 hour/day, working cycles similar to each other, andof relatively short duration (a few minutes), which are carried out via actions of the upper limbs. Onceestablished which tasks are actually repetitive and should be submitted to an analysis, the mostimportant problem is the quantification/assessment of repetitiveness.One suggestion which can be implemented in the field for frequency measurement, is that of counting,very carefully and analytically, all the technical actions, as defined in Table .1, and to then refer themto the time unit of reference (no. of technical actions per minute).Subsequently, an analysis of postures (the type of quantitative and qualitative joint involvement, thestatic or dynamic component of movement) will make it possible to obtain a general estimation of thedegree of repetitiveness and of the duration of single joint movements within the sequence of technicalactions.For a description of the technical actions it is better to make a video of the working tasks, which shouldthen be viewed in slow-motion.If the task is technically complex, the description of the action must absolutely be prepared together withpersonnel having specific experience in that task.Often, the company itself already has available documentation (for ex., times and methods workanalyzes) which extensively describes the carrying out of the task: such documentation includes thenumbered list and timing of successive movements or operations. For an efficient study of repetitivemovement tasks and, more specifically, to identify and count the technical actions, the following order ofactions is suggested.

a) Preparation of a videoThe work carried out during the shift by the operator, or by a homogeneous group of operators, issubmitted to a work analysis to establish the repetitive tasks characterized by cycles. It is sufficient tofilm a few cycles for every repetitive task (three or four). If the nature of the cycle makes it possible tocarry out operations in various different ways, then it may be useful to film 2 or 3 operators while they areworking on the same cycle. If there are technical obstacles to making a video of the operator from thefront, which would make it possible to film both arms at the same time, it is suggested to film the rightarm first, and then the left. The view field must include all the area from the shoulder, including all thetrunk, and the hand.

b) Detecting each single technical action

Technical actions have already been described as implying arthro-musculo-tendon activity of the upperlimbs: they should not be identified with the single joint movements, but rather with the total movements of one or more joint segments which enable the completion of a simple working task. As previouslyexplained, the aim of the MTM analysis is that of pinpointing the elementary movements necessary todetermine the time required to accomplish a given operation. The more incongruous the posture requiredfor the task, the longer the time required (e.g., because of the distance, etc.); or, the greater the forcerequired, the longer the time (weight of the object, degree of precision required, handling difficulties, etc.).Therefore, the presence of risk factors that may overload the upper limbs presupposes a lengthening of thetask execution times.The OCRA analysis starts from the need to analyze each risk factor singly, and then to put the exposurestudy together with the use of a single formula that enables a study of the results of all the possible various


2/10


3/10


3

The decision to base the analysis on the frequency of the technical actions enables an easier and

more objective assessment of this fundamental factor for the characterization of exposure torepetitive movements.

Technical actions, in fact, are commonly used in job planning: their definition and recognition are

both easy for technical personnel involved in production.Frequency calculation as suggested here also helps to avoid mistakes due to the fact that workers

have the possibility to increase or decrease their working pace, at least in those tasks where

productivity is pre-set (no. of parts processed per shift). In fact, the method bases frequencycalculations on:

a) the exact time available to carry out of the taskb) the number of cycles (or pieces) required per shiftc) the number of technical actions necessary to carry out a cycle.

The result obtained is actually the net average frequency, which is necessary to carry out eachworking task over a definite assigned period of time.

Examples for identifying and counting technical actions: it possible to find the films ofthe following examples in :

C: TRAINING EXAMPLES LEARNING TECHNICAL ACTIONSC- TRAINING EXAMPLES- ANALYSING TECHNICAL ACTIONS AND POSTURES


4/10


4

Tab.1

DEFINITION UPDATE OF TECHNICAL ACTIONS FOR THE STUDY OF

ACTION FREQUENCY

Edited by: Daniela Colombini, Michele Fanti

acronymNAME DEFINITION SYNONYMS SPECIFICATIONS

HO HOLD

The act of keeping an

object in hand, between

TAKE and POSITION,

for a period exceeding 5

sec. consecutive: it is a

static action.

keep in your

hand, keep in

prehension

The action should not be counted when

maintenance in the hand of the object takes

less than 5 sec. consecutive.

SUS SUSTAIN

The act of supporting,with the upper limb but

without taking, or the

body itself, for a period

exceeding 5 sec.

consecutive: it is a static

action.

Lean on thearm, forearm

support

The action should not be counted when thesupport of the body or object /s lasts less

than 5 sec.

INS INSERT

The act of putting an

object into a deep (25

mm) and narrow place(the distance between the

walls of the duct and the

item must not exceed 5

mm).

Introduce When introducing a component in a duct

(or support) of a length equal to or greater

than 25 mm, you will have the INSERTaction (if lower the action will be PLACE).

If the game between the two components is

non-existent (putting the couple upside

down it doesnt dissociate spontaneously)you will have the actions POSITION+

INSERT

EXT EXTRACT

The act of removing an

object or a tool from a

deep (at list 25 mm) and

narrow place (the game

between the walls of the

duct and the object of not

exceeding 5 mm).

When they bring out an object or a tool

from a duct (or support) of a length less

than 25 mm do not have the operation to

EXTRACT.

THR THREAD

The act of passing an

object from one side of a

passage ring shaped or a

ring shaped object on a

support

Dicasi di infilare un ago, di una corda o un

cavo in anelli, bullone in rondella, ecc..

Thread a needle, a rope or cable throw

rings, bolt in the washer, etc. ..


5/10


6/10


6

acronym NAME DEFINITION SYNONYMS SPECIFICATIONS

MOVMOVING

WEIGHT

The act of returning after the

actions REACH AND

TAKE A LOAD

If the load does not have the minimum

requirements outlined above, no

MOVING action will be counted

between the two actions TAKE and

POSITION

RAIRAISE

WEIGHT

The act of transferring a loadfrom lower position to an

higher position covering a

vertical distance of 50 cm at

least .

If the load does not have the minimumrequirements described, the action

RAISE will not be counted between the

two actions TAKE and POSITION.

LOW LOWERWEIGHT

The act of transferring a loadfrom higher position to a

lower position covering a

vertical distance of 50 cm at

least .

If the load does not have the minimumrequirements described, the action

LOWER will not be counted between

the two actions TAKE and POSITION.

ROT ROTATE

ROTATE action should be

considered when the subject

once taken in hand must be

positioned in a technically

different way: the change of

direction must be more than

90 , otherwise consider only

the action POSITION

revolve Every exchange of direction has to be

counted as technical action ROTATE.

For the tools we consider only TAKE

ad POSITION: IF YOU LOOK

ROTATION CHANGES CONSIDER

them ONLY AS Postural changes.

SCRSCREW-

UNSCREW

The act of manually turningscrewdrivers and other hand

tools in order to place a

component with a thread

You have to count a technical actionevery rotation until its completion

before a new grasp, remember that

before screwing is almost always

present the action TAKE (screwdriver,

tool). After every re -take of the hand, a

new action of screwing should be

counted. When the screwdriver are

rotated with the tips of fingers, you have

to count a SCREW action without

counting the actions TAKE

TUR TURN

The act of manually rotate

bolts, caps and other objectswith thread or rotational

movement of an object

around its axis

rotate the wheel,

unscrew a screw-cap

You have to count a technical action

every turn until its completion before anew grasp, remember that before TURN

is almost always present the

actionTAKE (screw, bolt, cap,

screwdriver). After every re-take , a new

action of TURN must be counted. When

the bolt or nut are rotated with the tips

of fingers, you have to count a TURN

action without counting the actions

TAKE


7/10


7

acronymNAME DEFINITION SYNONYMSSPECIFICATIONS

ROL ROLL

The act of tightening of

cable (or other similarcomponent) around apivot.

Count as a technical action every full turn

around the pivot

OPE OPEN

The act of actively open

the front of a tool designed

to cut or hold the object

being processed. The act of

actively open the object

that rotates on hinge (eg,

doors)

If the tool does not have a opening spring,

you have to count the action OPEN before

the action CLOSE (in this case the

equivalent of position). If on the contrary

the tool has a well-functioning spring, the

action will not be counted

CLO CLOSE

The act of actively close

the front of a tool designed

to grasp the object inproduction, or a rotating

door hinge (eg, doors)

The CLOSE action in case of closure of

gear to grab an object to be processed, is the

equivalent of POSITIONING. In case ofclosing of a tool such as scissors, use the

term CUT

CU

CUT

WITH

SHISSORS

The act of obtaining, with

sharp blades (scissors,

knives, cutters, scalpels or

similar), the division of an

object into two parts.

SHISSORSYou have to count one technical action for each

cut. If to `CUT you use only the part up to 1 / 3

from the tip of a scissors, you just count the

ation CUT and not the action OPEN the band.

After action TAKE, you have to count the

actions OPEN (if necessary), POSITION (only

the first cutoff point), CUT and continue to

count (OPEN) AND CUTfor the consecutive

cuts until you continue cutting along the same

lines. When you start to cut at another point by

moving the shissor, you have to count again the

action POSITION. When you get the cut by

sliding the middle between the two open blades,

after the action TAKE, you have to count OPEN

(if necessary), POSITION (only the first cutoff

point), then a single cut called SPREADING

CUT, until the first change of direction or

repositioning of scissors.

CUT

CUT

WITH

KNIVES

The act of obtaining, with

cutting blades, knives, the

division of an object into

two parts.

KNIVES

You have to count one technical action for

any cut (or any repositioning of the blade)or any change in the direction of the cut.

After the action TAKE you have to count

the action CUT (without the action

POSITION blade)

When using the knife for boning, when the

tip is used before the action of cutting, youhave to count also the action POSITION.


8/10


8

RIP RIP

The act of obtaining with

your hands the division of

an object into two parts.

You have to count one technical actino

for every rip

HIT HIT

The act of hitting with atool or directly with the

upper limb a working

point to obtain a

technical result

hammer, beat,strike

You will count a technical action ateach stroke on the surface.

BRU BRUSHING

The act of passing a tool

(brush, file, sandpaper,

cloth, etc. ..) on a surface.

paint Count as technical action each single

"passing" on the floor to be covered

with brush.

SAN SANDINGscrape Count as technical action each

"passing" on the plan to be treated.

CLE CLEANING

rub Count as technical action each

"passing" on the plan to betreated(single circular and / or linear

movements).

MAR MARKING

Mark Count as technical action each

"passing" of the pen (and / or gypsum,

and / or pencil, and / or pen) on the plan

to be treated (single circular movementsand / or linear).

WRI WRITE

The act of writing using

special instruments

dedicated.

drawing,

marking, tracing

It should be regarded as a

predominantly static action. if the lines

exceed the length of 2 cm, count each

change of direction of the action as 1

technical action.

SMO SMOOTH

The act of moving your

hand flat on a surface to

pave and / relax it

smooth, stretch Count as technical action each

"passing" on the plan to be treated

(single circular and / or linear

movements).

CRU CRUSH

The act to apply pressure

with your fingers on a

surface to obtain a

technical result

block, apply

pressure to paste

Typical action to obtain the adesion of

two parts, or enlargement of a surface

(making pizza, modeling). Each

crushing with one or more fingers

should be counted as a technical action.

SCR SCROLL

The act of sliding your

fingers on the top of anobject

Count as technicl action each linear

scrolling up to a new take of theobject.

THRW THROW

The act of imparting a

parabolic trajectory to an

object, to get to the

destination zone.

Tthis action is different from release

because in this case the object,

passively released, falls vertically to the

point of destination. Remember that

release must not be counted as a

technical action.


9/10


9

SHA SHAKE

The act of quickly moving

an object to obtain its

distension or the act of

shaking an object in orderto obtain a result (mixing

the content, etc. ..)

Count every shaking as an action

CURV CURVE

The act of procuring a

curvilinear deformation to

an object

INF INFLECT

The act of procuring a

deflection angle to an

object.

STR STRAIGHTENThe act to bring an objectto a deformed shape

straight

ALI ALIGN

The Act dictated by the

need to adapt an object to

obtain a technical result

(eg.: Locate, extract,

embed, etc..). The actionis characterized by short

and rapid movements.

adjust, arrange The action appears when after

positioning, the object needs micro

movements to be positioned properly or

if it is necessary to bring 2 items before

getting the union or the division. Youhave to count all micro movements as a

single technical action: if the phase of

adjustment last for more than 5 sec. you

have to count it as a static action.

EMB EMBED

The act of joining an

object to another when

provided with specific

system to fit union

match to fit Can often be preceded by the action

ARRANGE


10/10


10

WHAT YOU DONT HAVE TO COUNT AS TECHNICAL ACTION

WALKWithout carryng an objects

PASS

An object from an hand to the other

RELEASE

A tool or an

object

The action should not be counted as a technical

action when an object or a tool, once you have

finished to use, is not located in a specific point,but "released" for easy opening of the hand or

fingers (by passive return for or fall).

MOVE

A light objectRAISE

LOWER

CARRY

Documents

1-ANNEX%20frequency