ISO 4123:1979

Belt conveyors - Impact rings for carrying idlers and discs for return idlers - Main dimensions

Establishes the main dimensions of impact rings for carrying idlers and discs for return idlers used for the various types of belt conveyors.

Transporteurs à courroie — Disques amortisseurs pour rouleaux porteurs et disques anticolmatants pour rouleaux de retour — Dimensions principales

General Information

• Status: Published
• Publication Date: 31-Jan-1979
• ICS: 53.040.20 - Components for conveyors
• Technical Committee: ISO/TC 101 - Continuous mechanical handling equipment
• Drafting Committee: ISO/TC 101 - Continuous mechanical handling equipment
• Current Stage: 9093 - International Standard confirmed
• Start Date: 05-May-2025
• Completion Date: 13-Dec-2025

Overview - ISO 4123:1979 (Belt conveyors: Impact rings & return-idler discs)

ISO 4123:1979 defines the main dimensions for impact rings used on carrying idlers and for discs used on return idlers in belt conveyor systems. Intended for continuous mechanical handling equipment, this International Standard sets dimensional relationships so that impact rings and discs fit common idler sizes used in troughed, light‑duty and mobile/portable belt conveyors. The standard was published in 1979 and applies to conveyors covered by ISO 1537, ISO 2109 and ISO 2406.

Key topics and technical requirements

• Scope and field of application: Establishes principal dimensions for impact rings and return‑idler discs used with belt conveyors covered by related ISO idler standards.
• Dimensional alignment: Inner and outer diameters of impact rings and discs correspond to idler diameters specified in ISO 1537, ISO 2109 and ISO 2406 to ensure compatible fit.
• Disc types: Defines separate forms for return‑idler discs (Type A = inner disc; Type B = outer disc).
• Secure fixing: Diameters (denoted D and D1 in the standard) are to be chosen so the ring or disc can be securely fixed on the idler.
• Material requirement: Impact rings and discs shall be made of elastic material (for example, rubber) to provide impact absorption and wear resistance.
• Manufacturer discretion: Where detailed form or additional data are not specified, design details are left to the manufacturer’s discretion.
• Amendments noted: The standard indicates an additional diameter (114.3 mm) was to be added later.

Practical applications and users

ISO 4123:1979 is useful for:

• Conveyor designers and mechanical engineers specifying idler accessories.
• Idler and conveyor component manufacturers producing impact rings and return discs.
• Maintenance and reliability teams selecting replacement parts that match idler diameters.
• Procurement specialists ensuring component compatibility with conveyor systems.
• Industries handling bulk materials - mining, quarrying, aggregates, cement, ports, bulk terminals - where standard‑compatible impact protection and return‑idler components improve belt life and reduce spillage.

Related standards

• ISO 1537 - Troughed belt conveyors: idlers (reference for idler diameters)
• ISO 2109 - Light duty belt conveyors for loose bulk materials
• ISO 2406 - Mobile and portable conveyors - constructional specifications

By aligning impact‑ring and disc dimensions with established idler standards, ISO 4123:1979 helps ensure interchangeability, reliable mounting, and consistent impact protection across belt conveyor installations.

Standards Content (Sample)

INTERNATIONAL STANDARD
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MEIK,QYHAPOCIHAR OPrAHM3AIJMR fl0 CTAH~APTM3A~MM.ORGANISATION INTERNATIONALE DE NORMALISATION
Belt conveyors -
Impact rings for carrying idlers and discs for
return idlers -
Main dimensions
Transporteurs 2 courroie -
Disques amortisseurs pour rouleaux porteurs et disques an ticolma tan ts pour
rouleaux de retour
- Dimensions principales
First edition - 1979-02-01
Corrected and reprinted -
w
-
UDC 621.867.2
Ref. No. ISO 4123-1979 (E)
h
Desctiptors : conveyors, belt conveyors, idlers, accessories, specifications, dimensions.
Price based on 3 pages
FOREWORD
ISO (the International Organization for Standardization) is a worldwide federation
of national Standards institutes (ISO member bodies). The work of developing
International Standards is carried out through ISO technical committees. Every
member body interested in a subject for which a technical committee has been set
up 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.
Draft International Standards adopted by the technical committees are circulated
to the member bodies for approval before their acceptance as International
Standards by the ISO Council.
International Standard ISO 4123 was developed by Technical Committee
ISOfTC 101, Continuous mechanical handling equipment, and was circulated to the
member bodies in November 1977.
lt has been aprroved by the member bodies of the following countries :
Australia
France Poland
Austria
Germany, F. R. South Africa, Rep. of
Belgium India
Spain
Bulgaria Italy
Sweden
Czechoslovakia Mexico
Turkey
Denmark
Netherlands U.S.S.R.
Finland
Norway Yugoslavia
The member bodies of the following countries expressed disapproval of the
document on technicai grounds :
United Kingdom
U .S.A.
Q International Organkation for Standardkation, 1979 l
Printed in Switzerland
ISQ4123-1979(E)
INTERNATIONAL STANDARD
Belt conveyors - Impact rings for car
...

NORME INTERNATIONALE ISO 4123-1979 (FVERRATUM
Pub1 ié 1980-09- 15
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION l MEXAYHAPOAHASI OPTAHM3AUMJl l-I0 CTAHQAPTM3AUMM *ORGANISATION INTERNATIONALE DE NORMALISATION
Disques amortisseurs pour rouleaux porteurs et disques
Transporteurs à courroie -
anticolmatants pour rouleaux de retour - Dimensions principales
ERRATUM
Pages 2 et 3
Dans le tableau, première ligne :
Remplacer la valeur li4,3 par 108.
Sous le tableau, ajouter la note suivante :
NOTE - Le diamètre de 114,3 sera ajouté ultérieurement.

Page blanche
NORME INTERNATIONALE
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.ME))(LIYHAPDP(HAF OPrAHM3AUMR l-K) CTAHCIAPTIA3ALWl~RGANISATION INTERNATIONALE DE NORMALISATION
Transporteurs à courroie - Disques amortisseurs pour
rouleaux porteurs et disques anticolmatants pour rouleaux
de retour - Dimensions principales
Belt conveyors - Impact rings for carrying idlers and discs for return idlers - Main dimensions
Première édition - 1979-02-01
CDU 621.867.2 Réf. no : ISO 4123-1979 (F)
Descripteurs : transporteur, transporteur à courroie, roue folle, accessoire, spécification, dimension.
Prix basé sur 3 pages
AVANT-PROPOS
L’ISO (Organisation internationale de normalisation) est une fédération mondiale
d’organismes nationaux de normalisation (comités membresde I’ISO). L’élaboration
des Normes internationales est confiée aux comités techniques de I’ISO. Chaque
comité membre intéressé par une étude a le droit de faire partiedu comité technique
correspondant. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec I’ISO, participent également aux travaux.
Les projets de Normes internationales adoptés par les comités techniques sont
soumis aux comités membres pour approbation, avant leur acceptation comme
Normes internationales par le Conseil de I’ISO.
La Norme internationale ISO 4123 a été 6laborée par le comité technique
ISWTC 101, Engins de manutention continue, et a été soumise aux comités
membres en novembre 1977.
Les comités membres des pays suivants l’ont approuvée :
Afrique du Sud, Rép. d’ Pays-Bas
Espagne
Finlande Pologne
Allemagne, R. F.
France Suède
Australie
Inde Tchécoslovaquie
Autriche
Italie Turquie
Belgique
Bulgarie Mexique U.R.S.S.
Danemark Norvège Yougoslavie
Les com i tés membres des suivants l’ont désapprouvée pour des raisons
techniques :
Royaume-Uni
U.S.A.
0 Organisation internationale de normalisation, 1979 l
Imprimé en Suisse
...