SIST EN ISO 21181:2007

SLOVENSKI STANDARD
SIST EN ISO 21181:2007
01-april-2007
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Light conveyor belts - Determination of the relaxed elastic modulus (ISO 21181:2005)
Leichte Fördergurte - Bestimmung des relaxierten Elastizitätsmoduls (ISO 21181:2005)
Courroies transporteuses légeres - Détermination du module d'élasticité relaxé (ISO
21181:2005)
Ta slovenski standard je istoveten z: EN ISO 21181:2006
ICS:
53.040.20 Deli za transporterje Components for conveyors
SIST EN ISO 21181:2007 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN ISO 21181
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2006
ICS 53.040.10 Supersedes EN 1723:1999
English Version
Light conveyor belts - Determination of the relaxed elastic
modulus (ISO 21181:2005)
Courroies transporteuses légères - Détermination du Leichte Fördergurte - Bestimmung des relaxierten
module d'élasticité relaxé (ISO 21181:2005) Elastizitätsmoduls (ISO 21181:2005)
This European Standard was approved by CEN on 21 October 2006.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21181:2006: E
worldwide for CEN national Members.

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EN ISO 21181:2006 (E)
Foreword
The text of ISO 21181:2005 has been prepared by Technical Committee ISO/TC 41 "Pulleys and belts
(including veebelts)” of the International Organization for Standardization (ISO) and has been taken over as
EN ISO 21181:2006 by Technical Committee CEN/TC 188 "Conveyor belts", the secretariat of which is held
by BSI.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by May 2007, and conflicting national standards shall be withdrawn at the
latest by May 2007.
This document supersedes EN 1723:1999.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.

Endorsement notice
The text of ISO 21181:2005 has been approved by CEN as EN ISO 21181:2006 without any modifications.


2

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INTERNATIONAL ISO
STANDARD 21181
First edition
2005-11-01

Light conveyor belts — Determination of
the relaxed elastic modulus
Courroies transporteuses légères — Détermination du module
d'élasticité relaxé




Reference number
ISO 21181:2005(E)
©
ISO 2005

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ISO 21181:2005(E)
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ii © ISO 2005 – All rights reserved

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ISO 21181:2005(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of 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 of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21181 was prepared by Technical Committee ISO/TC 41, Pulleys and belts (including veebelts),
Subcommittee SC 3, Conveyor belts.
This International Standard is based on EN 1723:1999, prepared by CEN/TC 188.
© ISO 2005 – All rights reserved iii

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ISO 21181:2005(E)
Introduction
Many applications for light conveyor belts require that the belt is initially tensioned and there is no subsequent
change in belt length by adjustment of any rollers. In such cases the tensioning force in the belt changes
throughout the life of the belt because of two effects: permanent stretch and relaxation of the belt, both of
which change its real elastic modulus. It is vital to have a means of establishing the way in which the
tensioning forces will change; and this test applies a cyclic stretching between two defined states of elongation
over a large number of cycles. It has been found experimentally that the tensioning force drops in an
exponential way. It is possible to measure the tensioning force and then to calculate what is herein defined as
the “relaxed elastic modulus”. It is important to note that this is not a true elastic modulus, because it includes
an element of permanent stretch; but, except in cases where the permanent stretch is relatively large, it is a
measure of great practical value in determining final tensioning forces. This International Standard is designed
to meet the requirements for such applications.

iv © ISO 2005 – All rights reserved

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INTERNATIONAL STANDARD ISO 21181:2005(E)

Light conveyor belts — Determination of the relaxed elastic
modulus
1 Scope
This International Standard specifies a test method for the determination of the relaxed elastic modulus of light
conveyor belts according to ISO 21183-1, or other conveyor belts where ISO 9856 is not applicable.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 7500-1:2004, Metallic materials — Verification of static uniaxial testing machines — Part 1:
...