Tiêu chuẩn iso 00703 2017

INTERNATIONAL
STANDARD

ISO
703

Fourth edition
2017-01

Conveyor belts — Transverse flexibility
(troughability) — Test method
Courroies transporteuses — Flexibilité transversale (aptitude à la
mise en auge) — Méthode d’essai

Reference number
ISO 703:2017(E)
© ISO 2017


ISO 703 : 2 017(E)

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© ISO 2017 – All rights reserved


ISO 703:2017(E)

Contents

Page

Foreword ........................................................................................................................................................................................................................................ iv

Introduction .................................................................................................................................................................................................................................. v

1
2
3
4
5
6

Scope ................................................................................................................................................................................................................................. 1
Normative references ...................................................................................................................................................................................... 1
Terms and definitions ..................................................................................................................................................................................... 1
Symbols .......................................................................................................................................................................................................................... 1
Principle ........................................................................................................................................................................................................................ 1
Apparatus (see Figure 1) .............................................................................................................................................................................. 2

7

Test piece ...................................................................................................................................................................................................................... 3

8

Procedure ..................................................................................................................................................................................................................... 3

9
10

7.1
7.2

Dimensions ................................................................................................................................................................................................. 3
Conditioning .............................................................................................................................................................................................. 3

Calculation and expression o f results ............................................................................................................................................. 4
Test report................................................................................................................................................................................................................... 4

Bibliography ................................................................................................................................................................................................................................ 5

© ISO 2017 – All rights reserved

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ISO 703:2017(E)

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work o f preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters o f
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
di fferent types o f ISO documents should be noted. This document was dra fted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso .org/directives).
Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f
patent rights. ISO shall not be held responsible for identi fying any or all such patent rights. Details o f
any patent rights identified during the development o f the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso .org/patents).

Any trade name used in this document is in formation given for the convenience o f users and does not

constitute an endorsement.

For an explanation on the meaning o f ISO specific terms and expressions related to con formity assessment,

as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 41 Pulleys and belts (including veebelts),
Subcommittee SC 3, Conveyor belts.
This fourth edition of ISO 703 cancels and replaces ISO 703:2007, of which it constitutes a minor
revision.

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ISO 703:2017(E)

Introduction
A large number o f conveyor belts work in the shape o f a trough. I f a conveyor belt is too sti ff transversely
it does not rest on the central idler roller when unloaded. Its balance is then unstable and it is subject to
lateral travel, which may cause its destruction.
It is possible to make a section o f the conveyor belt take on the shape o f a trough under its own mass, by
suspending the section by its edges. However, this does not necessarily indicate what happens when the
conveyor belt is not carrying a load.
The results obtained from the test method specified in this document will, however, allow an
assessment to be made as to whether the troughing characteristics o f the conveyor belt are suitable for

the intended application.

© ISO 2017 – All rights reserved

v



ISO 703:2017(E)

INTERNATIONAL STANDARD

Conveyor belts — Transverse flexibility (troughability) —
Test method
1 Scope
T h i s do c u ment s p e c i fie s a te s t me tho d
conveyor b elt, e xpre s s e d a s a ratio ,

described in ISO 21183-1.
NO TE

for

de term i n i ng the tra n s vers e flexibi l ity (troughabi l ity) o f a

F/L . T he me tho d i s no t s u itable or va l id for l ight conveyor b elts a s

T he tra n s vers e “fle xibi l ity” de ter m i ne d b y the me tho d de s c r ib e d i n th i s do c u ment i s o n l y i nd i re c tl y

a s s o c i ate d with the i nvers e o f fle xu ra l mo du lu s a s s p e c i fie d i n I S O 178 . N or do e s it ta ke i nto co n s ideration the
d i fference s i n “fle xibi l ity” a s e xh ib ite d b y th re e -p o i nt a nd

strain and the thickness of the test piece.

fo u r-p oi nt b end i ng ,

wh ich ta ke s acco u nt o f the fle xu ra l

2 Normative re ferences
T he

fol lowi ng

do c u ments are re ferre d to i n the tex t i n s uch a way th at s ome or a l l o f thei r content

con s titute s re qu i rements o f th i s do c u ment. For date d re ference s , on ly the e d ition cite d app l ie s . For
u ndate d re ference s , the late s t e d ition o f the re ference d do c ument (i nclud i ng a ny amend ments) appl ie s .

ISO 583, Conveyor belts with a textile carcass — Total belt thickness and thickness of constitutive
elements — Test methods
ISO 7590, Steel cord conveyor belts — Methods for the determination of total thickness and cover thickness
ISO 18573, Conveyor belts — Test atmospheres and conditioning periods
3 Terms and definitions
No term s and defi nition s a re l i s te d i n th i s do c u ment.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at ctropedia .org/
— ISO Online browsing platform: available at .org/obp
4 Symbols
F

ver tic a l defle c tion i n te s t pie ce corre c te d

F1

ver tic a l defle c tion i n te s t pie ce, i n m i l l i me tre s (s e e

L

length o f tes t piece when laid flat, in mil limetres (equivalent to

d

thickness of the test piece, in millimetres (see Figure 2).

for

b elt th ickne s s , i n m i l l i me tre s

Figures 1 and 2)
full

width o f ins talled conveyor belt)

5 Principle

A test piece, consisting of a transverse section of belt of length, L , is suspended at both ends with the
c arr yi ng

face

upp ermo s t, s o that the upp er e dge s o f the s e end s are i n the s a me hori z onta l p lane .

© ISO 2017 – All rights reserved

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ISO 703:2017(E)

T he tra n s vers e flexibi l ity (trough abi l ity) i s de term i ne d b y me a s uri ng the ma xi mu m defle c tion,

test piece under its own weight. It is expressed as the ratio F/L .

F, of the

6 Apparatus (see Figure 1)
6.1

Two rigid horizontal bars ,

greater than the test length, L.

co nveniently s up p o rted. The uns up p o rted length o f the b ars s hall b e

Two clamps , to be attached to the ends of the test piece, with suspension lugs for attachment to the
suspending wires. The construction of the clamps shall allow for a rigid bar or straightedge to be placed
in contact with the belt, as shown in Figure 2
f
6.2

, to es tab lis h the datum line neces s ary

o r meas uring the

deflectio n. The clamp s s hall b e s u fficiently wide and rigid to maintain the width o f the tes t p ieces

fro m

6.3

free

curvature, and s hall exert no b ending mo ment which might influence the deflectio n o f the tes t p iece.

Four steel suspension wires ,

o f equal length, each with adj us tab le s tirrup s o n b o th ends

fo r

attachment to the horizontal bars and clamps. The attachments to the horizontal bars and clamps should
f
f
vertical during the test.
no t imp ede the

6.4

ree movement o

the adj us tab le s tirrup s when maintaining the s us p ens io n wires in the

Means o f measuring the deflection , F1 , to the nearest millimetre (see Figure 2).

Dimensions in millimetres

Key

1
2
3
4
5
6

four steel suspension wires
two rigid horizontal bars
two clamps
plumb line
test piece
rigid bar to establish datum line
Figure 1 — Typical apparatus for measuring transverse flexibility (troughability)

2

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ISO 703:2017(E)

7 Test piece

7.1 Dimensions

The test piece shall conform to the following requirements:
a) its form shall be a rectangular parallelepiped;
b) its length, L , shall be the overall width o f the installed conveyor belt, when laid flat;
c) its width, in the longitudinal direction of the belt, shall be (150 ± 2) mm;
d) its thickness, d, shall be the overall thickness of the conveyor belt.
7.2 Conditioning

Condition the test pieces in accordance with ISO 18573, using atmosphere A, B or C, and then carry out
the tests immediately a fter completion o f the conditioning period.

8 Procedure
Immediately be fore the test, ensure that the clamps are free to swivel and do not exert a bending force

on the test piece.

Measure the flat length, L , of the test piece in millimetres.

Measure the thickness, d, of the test piece, in millimetres, in accordance with ISO 583 or ISO 7590.
Fit the test piece, carrying face uppermost, while in the flat position, into the suspended clamps.
Allow the test piece to fall under its own weight from the flat position into the troughed position.
Adjust the apparatus so that the suspending forces act vertically throughout the test period.
A fter 5 min, measure the vertical deflection, F1 , of the
measurement the dimension 0,5 d to give the value for F.

test piece (see Figure 2) and add to this

Key

d thickness of test piece
F1 vertical deflection

1 datum line

Figure 2 — Determination o f deflection, F1

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ISO 703:2017(E)

9 Calculation and expression o f results

Calculate the value of F from Formula (1):
F = F1 + 0,5 d

(1)

Express the results of the measurements in the form of F/L .
10 Test report

The test report shall contain the following information:
a) reference to this document, i.e. ISO 703;
b)

identi fic ation o f the conveyor b elt te s te d;

c)
d)
e)
f)
g)

the test length, L (see Clause 4);
the thickness of the test piece, d (see 7.1);
the conditioning atmosphere used (A, B or C);
the value of ratio F/L;
the date of the test.

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ISO 703:2017(E)

Bibliography

[1]
[2]

ISO 21183-1, Light conveyor belts — Part 1: Principal characteristics and applications
ISO 178, Plastics  —  Determination  of  flexural  properties

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ISO 703:2017(E)

ICS  53.040.20

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