Tiêu chuẩn iso 06789 2 2017

b This document inclu es detai ed methods for calculation of the u c rtainty bu g et w hich shal be pe formed for each in ivid al t ool.. A ssembl y tools for scr ews and nuts — Hand tor

A ssembl y tools for scr ews and nuts —

Part 2:

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A ll rig hts r eserved Unles otherw ise spe ified, nopar of this p blc tion ma y be r epr od c d or utilz d otherw ise in an form

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written permis ion Permis ion c n be req esed from either ISO at the ad r es below or ISO’s member bod y in the c u try of

F reword i v

Introduction v

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms, definitio s and symbols 1

3.1 Te msan definitions 2

3.2 Symb ls, desig nations an u it 2

4 Req irements for calbration 4

4.1 Calbration d ring use 4

4.2 Calbration method 4

4.3 Calbration sys em 4

5 Me surement error 5

5.1 Calculation of the r elative measur ement e r or 5

5.2 Exemplary calculations of the r elative measur ement e r or 5

5.2.1 Example 1 5

5.2.2 Example 2 6

6 So rc es of u c er tainty 7

6.1 General 7

6.2 Ev luation of T ype B u c rtainties due to the tor que to l 8

6.2.1 S ale, dial or displa y resolution, r 8

6.2.2 Variation d e to the r eproducibi ty of the torqueto l, b r ep

1 6.2.3 Variation d e to the inte fac betwe n the torque to l and the calbration sys em 1

6.2.4 Variation d e to the v riation of the for ce lo ding point , b l

1 6.3 Ev luation of T ype A u c rtainty d e to the torque to l 1

6.3.1 General 1

6.3.2 Variation d e to the r epeatabi ty of the tor que to l, b r e

1 7 Deter minatio of the calbration r esult 13

7.1 Dete mination of the r elative s an ar d measur ement u c rtainty, w .13 7.2 Dete mination of the r elative ex panded measur ement u c rtainty, W 14 7.3 Dete mination of the r elative measur ement u c rtainty inte v l, W’ 14 8 Calbratio c er tificate 15

A nne x A (informative)Calculation example for an indicating tor que to l (T ype I 16

A nne x B (informative)Calculation example for a set ing tor que to l (T ype I ) 25 A nne x C (normative) Minimum requirements for the calbr atio of the torque me surement devic e and the estimation of its me sur ement unc ertainty 34 Biblog raphy 41

ISO (he Int ernational Org nization for Stan ardization) is a worldwidefede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Stan ards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a lshed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www iso org dir ctives)

A tt ention is drawn t o the p s ibi ity that some of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such p t ent right Detais of

any p t ent right identified d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www iso org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

F or an ex lanation on the v lu tary natur of s an ards, the meaning of ISO spe if ic t erms an

ex r s ions r lat ed t o conformity as es ment, as wel as information a out ISO’ s adhe enc t o the

World Trade Org nization (WTO) principles in the Te hnical Bar ie s t o Trade (TBT) se the folowing

URL: www iso org iso / for word html

This document was pr p r d b Te h ical C mmitt ee ISO/TC 2 , Smal to l s , Subcommitt ee SC 1 ,

As s embly to l s fr s c rews a d n t , ple s a d nip e s

This firs edition of ISO 6 8 - 2, t og ethe with ISO 6 8 -1, canc ls and r plac s ISO 6 8 :2 0 w hich

has be n t ech ical y r vised with chang es as fol ow s

a) ISO 6 8 :2 0 has be n divided int o two p rt ISO 6 89:2 0 has be ome ISO 6 8 -1 w hich

spe if ies the r q ir ment for design an man factur inclu ing the cont ent of a de laration of

conformanc This document spe if ies the r q ir ment for trac a le c rtificat es of calbration

It inclu es a method for calculation of u c rtainties an pro ides a method for cal bration ofthe

t orq e measur ment devic used for cal brating han t orq e t ools

b) This document inclu es detai ed methods for calculation of the u c rtainty bu g et w hich shal be

pe formed for each in ivid al t ool

c) This document inclu es ex mplecalculations that ar pro ided for dife ent ty esof t orq e t ool

d) Annex C pro ides r q ir ment for calbrating the t orq e measur ment devic w he e the

cal bration la orat ory does not uti iz a national s an ard giving such r q ir ment

A l s of al p rt in theISO 6 8 se ies can befou d on the ISO websit e

The r vision of ISO 6 8 :2 0 has be n designed t o achieve the folowing impro ement

ISO 6 8 has be n spl t t o pro ide two levels of documentation It r co niz s the dife ent ne ds of

dife ent use s of the s an ard

ISO 6 8 -1 contin es t o pro ide designe s an man factur rs with r lev nt minimum r q ir ment

for thedevelo ment, prod ction an documentation of han t orq e t ools

This document pro ides detai ed methods for calculation of unc rtainties an r q ir ment for

calbrations This wi l alow use s of calbration se vic s t o mor easiy comp r the calbrations from

dife ent la orat ories Ad itionaly, minimum r q ir ment for the calbration of t orq e measur ment

devic s ar desc ibed in Annex C

The purpose of this document is t o define the r q ir ment for a calbration in w hich the sour es of

unc rtainty ar ev luat ed an used t o def ine the rang e of v lues within w hich the r adings pro a ly

fal Ad itional unc rtainties ma exis in the use of the t orq e t ool The ev luation of u c rtainties

for each in ivid al t ool is time-consuming an w he e the e ar suff icient data t o es imat e the Ty e B

unc rtainty comp nent b s atis ical means, it is ac epta le t o use these v lues for a given model of

t orq e t ool, pro iding that he u c rtainty component ar subje t t o pe iodic r view

A ssembl y tools for scr ews and nuts — Hand torque tools —

Part 2:

This document spe ifies the method for the calbration of han t orq e t ools an desc ibes the method

of calculation of measur ment u c rtainties for the calbration

This document spe ifies the minimum r q ir ment for the calbration of the t orq e measur ment

devic w he e the r lative measur ment unc rtainty int erv l, W´

md, is not alr ady pro ided b a

trac a le calbration c rtificat e

ISO 6 89 is a plca le for the st ep b st ep ( tatic) an contin ous (q asi-s atic) calbration of t orq e

measur ment devic s, the t orq e of w hich is defined b measuring of the elas ic form chang e of a

deforma le b dy or a measur d v ria le w hich is in pro ortion t o the torq e

This document a ples t o han t orq e t ools w hich ar clas if ied as in icating t orq e t ools (Ty e I) an

set ing t orq e t ools (Ty e I )

NOTE Han torq e t ools covered by this document are the ones identif ied in ISO 170 :2 0 by reference

n mb r 6 1 0 1 0, 6 1 0 1 1 an 6 1 0 1 0, 6 1 0 1 1 an 6 1 0 14 0, 6 1 0 1 0 ISO 170 is cur ently

u der revision In the ne t edition, torq e t ools wil b moved t o an own clause, an with this chang the

reference n mb r wil also chang e an ad itionalreference n mb r wil b ad ed

2 Normati ve r eferences

The folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment ) a ples

ISO 6 8 -1:2 1 , As sembly to l s f r sc rews a d n t — Ha d torq e to ls — Part 1: R eq ir ments a d

meth ds fr des ig c on orma ce tes tin a d q alt y c onorma c e tes tin : minimum r q ir ments fr

declaratio o c onorma c e

ISO/IEC 1 0 5, G ene al r q ir ments fr the c ompetenc e o tes tin a d c albratio la oratories

3 Terms, definitions and symbols

F or the purp ses of this document, thet ermsan definitions given in ISO 6 89-1 an the folowing a ply

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— IECEle tro edia: a aia le at ht p:/ www ele tro edia org

— ISO Onlne brow sing plat orm:a ai a le at ht p:/ www iso org o p

3.1 Terms and definitions

3.1.1

Ty e A evaluatio (of uncertainty)

method of ev luation of u c rtainty b the s atis ical analy sis of se iesof o se v tions

Not e 1 to entry: T ese data are taken directly from the me surements o tained d ring calibration of e ch torq e

t ool an can ot b prepared in ad ance

[ SOURCE:ISO/IEC Guide 98-3:2 0 , 2.3.2, modif ied — Not e 1 t o entry has be n ad ed.]

3.1.2

Ty e B ev aluatio (of uncertainty)

method of ev luation of u c rtainty b means othe than the s atis ical analy sis of se ies of o se v tions

[ SOURCE:ISO/IEC Guide 98-3:2 0 , 2.3.3]

3.1.3

calbratio sy stem

combination of a measur ment devic an the lo ding sy st em for a plcation of t orq e that act as the

measur ment tan ard for the han t orq e t ool

Not e 1t o entry: A calibration sy stem can also b used as a t orq e me surement syst em as def ined in ISO 6 8 -1

reference me surement standard

measur ment tan ard designat ed for the calbration of othe measur ment s an ards for q antitiesof

a given kin in a given org nization or at a given location

[ SOURCE:ISO Guide 9 :2 0 , 5.6]

3.1.6

me surement er or

measur d q antity v lue min s a r fe enc q antity v lue

[ SOURCE:ISO/IEC Guide 99:2 0 , 2.1 , modif ied — Not es 1and 2 t o entry ha ebe n omitt ed.]

3.2 Symbols, desig nations and units

The designations used in this document ar in icat ed in Ta le1

Table 1 — Symbols, designatio s and units

Stated relative me surement er or of the me surement device %

NO E Whie N∙m is the u it c mmonly sed, the outp t sig al c n be dete ted in various u it , e.g voltage

Symb l Designation Unit

Variation d e t o g ometric efects of the int erface b tween the outp t drive of the

torq e to l an the calibration sy st em

Me surement h st eresis er or of the zero signal afer lo ding N∙m

I In icated value of me surement device without zero-value compensation N∙m

Covera e fact or k = 2 ap lied t o the relative me surement u certainty to achieve a

conf idence levelof ap ro imately 9 %

Component of w d e t o g ometric efects of the interface b tween the outp t drive

of the t orq e to l an the calibration sy st em

Relativ e stan ard me surement u certainty of the me surement device at the

calibration t orq e

R elative stan ard me surement u certainty d e t o resolution of the display of the

torq e to l (T pe I an T pe I Clas es A, D an G only)

NO E Whie N∙m is the u it c mmonly sed, the outp t ig al c n be dete ted in various u it , e.g voltage

Table 1 (c ontin ed)

Symb l Designation Unit

W Relativ e p n ed me surement u certainty of the torq e tool at the calibration torq e %

W′ R elative me surement u certainty int erv al of the t orq e t ool at the calibration t orq e %

W

md

Relativ e e pan ed me surement u certainty ofthe me surement device at the

calibration t orq e

%

W′

md

Relative me surement u certainty interval of the me surement device at the

calibration t orq e

R elative me surement u certainty interval of the reference me surement stan ard %

X In icated value of me surement device with zero-value compensation N∙m

NO E Whie N∙m is the u it c mmonly sed, the outp t sig al c n be dete ted in various u it , e.g voltage

4 Requir ements for cal bration

4.1 Cal bration dur ing use

If the use uti z s proc d r s for the control of t es devic s, t orq e t ools shal be inclu ed in these

proc d r s The int erv l betwe n calbrations shal be chosen on the b sis of the fact ors of o e ation

such as r q ir d ma imum pe mis ible measur ment e ror, fr q ency of use, ty ical lo d d ring

o e ation as wel as ambient con itions d ring o e ation an st orag e con itions The int erv l shal

be ada t ed ac ording t o the proc d r s spe if ied for the control of t es devic s an b ev luating the

r sult g ined d ring suc es ive calbrations

If the use does not uti z a control proc d r , a pe iod of 1 months, or 50 0 cycles, w hicheve oc urs

firs , ma be taken as default v lues for the int erv l betwe n calbrations The int erv l s art with the

firs use of the t orq e t ool

Short er int erv l between calbrations ma be used if r q ir d b the use , their cust ome or b

legislation

The t orq e t ool shal be cal brat ed w hen it has be n subje t ed t o an o e lo d gr at er than the v lues

given in ISO 6 8 -1:2 1 , 5.1.6, aft er r p ir, or aft er any impro e han l ng w hich might influenc the

t orq e t ool pe formanc an the fulfilment of the q alty conformanc r q ir ment

4.2 Cal bration method

The method for the calbration of thet orq e t ools shal be in ac ordanc with the measur ment method

of ISO 6 8 -1:2 1 , Clause 6 Ad itionaly, the r q ir ment for the t orq e measur ment devic def ined

in ISO 6 89-1:2 1 , 6.1is r plac d b 4.3

4.3 Cal bration system

The cal bration sy st em shal be chosen t o be suita le for the measur ment of the spe if ied rang e of the

t orq e t ool

Table 1 (c ontin ed)

A t each targ et v lue, the r lative u c rtainty int erv l, W′

md, of the measur ment devic shal not ex ce d

1 4 ofthe ex e t ed ma imum r lative u c rtainty int erv l of the t orq e t ool, W′

The measur ment devic shal ha e a v ld calbration c rtificat e is ued b a la orat ory me ting

the r q ir ment of ISO/IEC 1 0 5 Alt ernatively, the measur ment devic shal be calbrat ed b a

la orat ory maintaining the national measur ment s an ard

If the use does not uti iz a control proc d r , a pe iod of 24 months shal be the ma imum int erv l

betwe n calbrations

The measur ment devic shal be r -calbrat ed if it was ex osed t o an o e lo d larg er than 2 % of

T

E

, aft er a r p ir has be n car ied out or aft er an impro e use w hich can influenc the measur ment

unc rtainty

5.1 Calculation of the relati ve measurement error

The calbration v lues shal be measur d an r corded ac ording t o the r q ir ment in

j = 1, 2, …, n is the n mbe of in ivid al measur ment at each calbration t orq e

5.2 Ex mplary calculations of the r elati ve measurement er ror

5.2.1 Example 1

Calculation of the r lative measur ment e ror of in icating an set ing t orq e t ools (ex cept Ty e I ,

Clas B, C, E an F):

— in icat ed v lue of dial, me hanical scaleor displa (Ty e I, Clas es A, B, C, D an E), or

— set v lue of me hanical scale or displa (Ty e I , Clas es A, D an G):

— nominal v lue set Ty e I , Clas B an E), or

— lowes spe if ied t orq e v lue or pr -set v lue (Ty e I , Clas Can F):

The element of u c rtainty as ociat ed with the calbration of a t orq e t ool shal be de ived from at

leas one of thetwo folowing methodolo ies

— The unc rtainties shal be es a lshed using the proc d r s as set out in 6.2 Whe e a la orat ory or

man factur r has sufficient data as def ined in 6.2, this v lue ma be det ermined s atis ical y for a

suff icient n mbe of spe imen (at leas 1 ) of a model of t ool, and it det ermination does not ne d

t o be r peat ed each time for futur calbrations of this model The v ldity of this v lue shal be

r viewed sy st ematical y

— The unc rtainties shal be taken from man factur rs or othe third-p rty data Car shal betaken

t o ensur that any such data can be sufficiently v ldat ed an r prod c d in the la orat ory

E AMP E Ex mples of calculations are provided for T pe I wrenches in An e A an T pe I wrenches in

An e B

6.2 Evaluation of T ype B unc ertainties due to the torque tool

6.2.1 Scale, dial or display resolutio , r

6.2.1.1 Deter minatio of the resolutio , r, with analog ue s ales or dials

The t orq e v lue shal be r ad from the position of the active or mo ing cursor or point er on a scale or

dial Sla e point ers (memory in icat ors) shal not be used w hen taking the r adings

Whe e the p int er tip width is les than 1 5 of the scale or dial inc ement, the r solution is 1 5 of the

scale or dial inc ement v lue Whe e the point er tip width is eq al t o or gr at er than 1 5 but les than

1 2 of the scale or dial inc ement, the r solution is 1 2 of the scale or dial inc ement v lue Whe e the

p int er tip width is gr at er than 1 2 of the scale or dial inc ement, the r solution is the scale or dial

inc ement v lue

a)Examples of s ales and dials

b)Scale or dial w here pointer tip width is les

than or eq al to 1/5 inc ement width

c) Scale or dial w here pointer tip width is larg er

than 1/5 but les than or equal to 1/

inc ement width

Key

1 main s ale or dial incr ement in these examples 1N∙m)

Figure 1 — Examples of diferent pointer widths of s ales and dials

The r solution in Figur 1b)is det ermined as: r = × ⋅ = ⋅

6.2.1.2 Determinatio of the r esolutio , r, w ith micrometer s ales

Whe e the t orq e t ool uti iz s a “ mic omet er” scale, a se on set of scale marks a pro riat e t o the main

scale ma be used t o alow dir ct ractional r ading of the t orq e v lue

Whe e the e is no se on ary scale, it r solution is 1 2 of the main scale inc ement v lue Whe e the e

is a se on ary scale, the r solution is 1 2 of the se on ary scale inc ement v lue

a)Mic ometer without secondary s ale mar ks b)Mic ometer wit h seco dary s ale mar ks

c) Partial y co ered seco dary s ale

Key

1 main s ale incr ement in these examples 1 N∙m)

2 secon ary s ale incr ement in these examples 1N∙m)

Figure 2 — Examples of mic ometer s ales

The r solution in Figur 2 a) is det ermined as: r = × ⋅ = ⋅

6.2.1.3 Deter minatio of the resolutio , r, with dig ital s ales or dials

F or t orq e t ools with a digital scale, dial or displa ther solution, r, shal be det ermined as folow s

The v lue of r shal bea single inc ement of the las active digit, pro ided the displa does not luctuat e

b mor than one digit w hen the devic is at the lowes calbrat ed t orq e v lue Whe e the v lues

fluctuat e b mor than one digit w hen the devic is at the lowes calbrat ed t orq e v lue, the v lue of r

shal be a single inc ement of the las active digit plus one half of the fluctuation rang e;se Ta le 2

Table 2— Examples of resolutio

C se

R esolution

N·m

E ample 1 Ex mple 2 E ample 3

R eprod cibi ity is afe t ed b the a i ity t o identify ex ctly the v lue at w hich lo ding should be st op ed

for in icating t orq e t ools Ty e I and the a i ity of the me hanism t o r turn in ex ctly the same plac

each time aft er adjus ment of the t ool in the case of set ing t orq e t ools Ty e I F or b th Ty e I an

Ty e I t ools, it inclu es p rala e rors

F or t orq e t ools of al ty es, the folowing method is desc ibed for the det ermination of r prod cibi ity,

b

rep

The t ool shal be subje t ed t o the lo ding seq enc def ined in ISO 6 8 -1:2 1 , 6.5, at the lowes

spe ified t orq e v lue only an the v lues r corded The seq enc shal be pe formed four times an

the t orq e t ool shal be r mo ed from the calbration sy st em between each seq enc Whe e mor than

one o e at or pe forms such calbrations, the seq enc s wi be dis ribut ed betwe n o e at ors

Thev riation d e t o the r prod cibi ty of the t orq e t ool is calculat ed using F ormula (3):

(4 )

w he e

i = 1, …, 4 is the n mbe of the se ies;

j = 1, 2, …, n is the n mbe of in ivid al measur ment for se ies i with n =5

6.2.3 Var iatio d e to the interfac e betwe n the torque tool and the calbration system

Figure 3— Schematic interfaces betwe n the torq e tool and the calbratio sy stem

6.2.3.2 Variation due to g eometr ic efects of the o tput dri ve of the torque tool, b

od

Rat chet , hex g on an sq ar drive output of the t orq e t ool in p rticular ha e an influenc sinc

they can pot entialy run out of true an if not used in the same orientation each time, they can cause

v riation of r ading Int er hang ea le drive en s can also cause v riation

Int er hang ea le drive en s of the t orq e t ool inclu ing the c ntr dis anc shal be identif ied an

document ed

The folowing method is desc ibed for the det ermination of the output drive v riation, b

od This v lue

ma be det ermined s atis icaly for a sufficient n mbe of spe imen (at leas 1 ) of a model of t ool an

it det ermination does not ne d t o be r peat ed each time for futur cal brations of this model Whe e

the output drive is not ca a le of rotation, this v riation shal be set t o z ro

The t ool shal be positioned on the calbration sy st em ac ording t o ISO 6 8 -1:2 1 , 6.5, an subje t ed

t o five pr lo dings at he lower lmit v lue of the measur ment rang e, T

in

The t orq e t ool is r mo ed from the cal bration sy st em an the output drive is rotat ed b 6 °

(hex g onal drive output) or 90° ( q ar drive output) Ten measur ment ar r corded for each of at

leas four positions dis ribut ed evenly o e 3 0 at the lowe l mit v lue of the measur ment rang e,

T

in

, without changing the lo d a plcation p int

Thev ariation d e t o the influenc of the output drive is calculat ed using F ormula (5):

Themean v alue of the measur ment e ies is calculat ed using F ormula (4 ) with n = 1

6.2.3.3 Var iation due to g eometric efects of the interfac e betwe n the o tput dr i ve of the

torque to l and the calbratio system, b

int

Hex g on and sq ar drive int erfac s betwe n the output drive of the t orq e t ool and the calbration

sy st em ha e an influenc sinc they can pot entialy ru out of true an if not used in the same

orientation each time, they can cause v riation of r ading

The int erfac betwe n the output drive of the t orq e t ool an the calbration sy st em shal be identif ied

an document ed

The folowing method is desc ibed for the det ermination of the v riation b

int

d e t o the drive int erfac

This v alue ma be det ermined s atis icaly for a sufficient n mbe of spe imens (at leas 1 ) of a model

of t ool an it det ermination does not ne d t o be r peat ed each time for futur calbrations of this model

The t ool shal be positioned on the calbration sy st em ac ording t o ISO 6 8 -1:2 1 , 6.5, an subje t ed

t o f ive pr lo dings at the lowe lmit v lue of the measur ment rang e, T

in

The t orq e t ool is r mo ed from the cal bration sy st em an the drive int erfac is rotat ed b 6 °

(hex g onal drive output) or 90° ( q ar drive output) Ten measur ment ar r corded for each of at

leas four p sitions dis ribut ed evenly o e 3 0 at the lowe l mit v lue of the measur ment rang e,

T

in

, without changing the lo d a plcation p int

Thev ariation d e t o the influenc of the drive int erfac is calculat ed using F ormula (6):

Themean v alue of the measur ment e ies is calculat ed using F ormula (4 ) with n = 1

6.2.4 Var iatio d e to the var iatio of the for c e loading point , b

l

Mos t orq e wr nches ha e some v riation in t orq e o se ved depen ing on the ex ct for e lo ding

p int on the han le This does a ply t o b th in icating an set ing wr nches, but not t o t orq e

sc ewdrive s of eithe ty e F or t orq e sc ewdrive s, the v lue of b

lshal be set t o z ro

Whe e the lo ding p int is not marked on the t orq et ool an no man factur r information is a ai a le,

the dimension from the a isof rotation t o the lo ding p int used shal be document ed

The folowing method is desc ibed for the det ermination of the for e lo ding p int v riation, b

lThis

v lue ma be det ermined s atis ical y for a suff icient n mbe of spe imens (at leas 1 ) of a model of

t ool an it det ermination does not ne d t o be r peat ed each time for futur calbrations of this model

The t ool shal be positioned on the calbration sy st em ac ording t o ISO 6 8 -1:2 1 , 6.5, an subje t ed

t o f ive pr lo dings at the lowe lmit v lue of the measur ment rang e, T

in

Ten measur ment ar then r corded for each of two p sitions with changed for e lo ding p int, at the

lowe lmit v lue of the measur ment rang e, T

in The two for elo ding p int shal be 1 mm on eithe

side of the c ntr of the han hold p sition or the marked lo ding p int

The mean v lue of the 1 v lues at the long es leve length ar subtract ed from the mean v lue of the

measur ment of the short es leve length and this v lue is def ined asthe for e lo ding p int v riation,

Only one Ty e A unc rtainty is conside ed in thisdocument When calbrat ed in ac ordanc with 4.2, a

v riation of r adings wi be o se ved at each calbration t orq e This a ples b th t o Ty e I an Ty e

7 Determination of the cal bration result

7.1 Determination of the relati ve standard measurement unc er tainty, w

The r lative s an ard measur ment u c rtainty, w, as igned t o the t orq e t ool at each calbration p int

is given for uncor elat ed input q antities b F ormulae (1 ) an (1 )

F or in icating t orq e t ools:

Be a use r adings ar taken twic (at the scale’ s z ro p int or minimum, r spe tively, an at the

cal bration v lue), the measur ment u c rtainty of the r solution, r, a pears in the r sult twic These

two ran om fractions ar ad ed up g eometrical y

F or set ing t orq e t ools:

The formulae for calculating element of the unc rtainty ar shown in Ta le 3 Each r sulting element of

w shal firs be rou ded t o thr e de imal plac s befor being combined in F ormula (1 ) or F ormula (1 )

Table 3 — Distrib tio functio s for calculating the relative standard me surement

uncertainties for characteristic values calculated from the v ariatio s determined

Uncertainty du e to the variation in the s ale,

dial or display resolution, w

Xr

Uncertainty d e t o g eometric efects of the

outp t drive of the t orq e t ool, w

Xo

o

r,

Uncertainty d e t o g eometric efects of the

interface b tween the outp t drive of the

t orq e t ool an the calibration sy st em, w

Xint

int

r,

Xl

nX

7.2 Deter mination of the relati ve e x panded me surement unc er tainty, W

The r lative ex an ed measur ment u c rtainty, W, of the cal bration r sult for the t orq e t ool is

calculat ed from the s andard measur ment u c rtainty b multiplcation b thecoverag e fact or, k The

default v lue of k = 2 A che k shal be made in orde t o ensur a conf idenc int erv l of a pro imat ely

9 % The v lue for w shal f irs be rou ded t o thr e de imal plac s

NOTE F rther information on the value of k can b determined from ISO/IE Guide 9 -3:2 0 , An ex es C

an G

7.3 Deter mination of the relati ve me surement unc ertainty interval, W’

The r lative unc rtainty int erv l, W’, of a calbration inclu ing al sy st ematic an ran om component

shal be calculat ed using F ormula (1 ):

8 Cal bration c ertificate

Calbration c rtif icat es in ac ordanc with this document shal comply with ISO/IEC1 0 5 an contain

at leas the folowing ad itional information:

a) s at ement that it is a c rtificat e of calbration in ac ordanc with this documen

b) identif ication ( y e an se ial n mbe )of the t orq e t ool;

c) w he e an int er hang ea le element has be n used with the t ool, the efe tive length or dimension of

that int er hang ea le element shal be r corded;

d) spe ified t orq e rang e or f ix ed t orq e v lue of the t orq e t ool;

e) identif ication ( y e an se ial n mbe ) of the measur ment devic w he e the calbration has not

be n pe formed b a la orat ory me ting the r q ir ment of ISO/IEC 1 0 5;

f) dir ction()of o e ation;

g) al v lues r corded d ring calbration ( e ISO 6 8 -1:2 1 , 6.5);

h) for al tools exc pt set ing to ls Ty e I Clas B, C, E an F, the mean v lue, X

r, at each

cal bration point;

i) for set ing t ools Ty e I Clas B, C, E an F, the nominal t orq e an mean v lue, X

r

;

j) r lative ex an ed u c rtainty of thet orq et ool, W, for the mean v lue at each calbration poin

k) r lative measur ment unc rtainty int erv l, W′ at each calbration p int

A nnex A

Calculation example for an indicating torque tool (T ype I)

A 1 Indicating torque tool, T ype I, Clas C

Torque wrench: Rigid housing an ele tronic measur ment with a fix ed rat chet sq ar drive

Ex e t ed r lative u c rtainty int erv l, W′ ± %

Calbrat ed in a clockwise dir ction only Int erfac d t o calbration devic with an ada t er

A 2 Relati ve measurement error, a

susing F ormula (2) an X

rusing F ormula ( 9)

—

a

s,

—

a

s,

a

s,

A 3.2 Reproducibi ity (see 6.2.2)

A 3.2.1 Var iation due to the repr oducibiity, b

r ep

Ta le A.3 gives the v lues o se ved ac ording t o 6.2.2

Table A.1 (c ontin ed)

r,

r,

A 3.3 Geometric efects of the output dr i ve of the torque tool (see 6.2.3.2)

A 3.3.1 Variation due to g eometric efects of the output dri ve of the torque tool, b

od

Ta le A.5 gives the v lues o se ved w hen rotating the output drive ac ording t o 6.2.3.2