ISO 255

Belt drives — Pulleys for V-belts (system based on datum width) — Geometrical inspection of grooves

This document specifies the methods of checking the regularity of the grooves and pulleys for V-belts specified in the system based on datum width. The grooved pulleys may be designed for use with classical or narrow V-belts. Inspection parameters and tolerances of grooved pulleys are covered by appropriate International Standards.

Transmissions par courroies — Poulies à gorges pour courroies trapézoïdales (système basé sur la largeur de référence) — Contrôle géométrique des gorges

Le présent document spécifie les méthodes de contrôle de la régularité des gorges et des poulies pour courroies trapézoïdales spécifiées dans le système basé sur la largeur de référence. Les poulies à gorges peuvent être conçues pour être utilisées avec des courroies trapézoïdales classiques ou étroites. Les paramètres de contrôle et les tolérances des poulies à gorges sont traités dans les Normes internationales appropriées.

General Information

• Status: Not Published
• Publication Date: 01-Feb-2023
• ICS: 21.220.10 - Belt drives and their components
• Technical Committee: ISO/TC 41/SC 1 - Friction
• Drafting Committee: ISO/TC 41/SC 1 - Friction
• Current Stage: 6060 - International Standard published
• Start Date: 02-Feb-2023
• Due Date: 15-May-2023
• Completion Date: 02-Feb-2023

Relations

• Revises: ISO 255:1990 - Belt drives — Pulleys for V-belts (system based on datum width) — Geometrical inspection of grooves
• Effective Date: 06-Jun-2022

Standards Content (Sample)

ISO/TC 41/SC 1
Date: 2022-12-0609
ISO 255:2022(E)
ISO/TC 41/SC 1/WG
Secretariat: AFNOR
Belt drives — Pulleys for V-belts (system based on datum width) — Geometrical
inspection of grooves

Transmissions par courroies — Poulies à gorges pour courroies trapézoïdales (système

basé sur la largeur de référence) — Contrôle géométrique des gorges
---------------------- Page: 1 ----------------------
ISO/FDIS 255:2022(E)
© ISO 2022

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or

utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,

or posting on the internet or an intranet, without prior written permission. Permission can be

requested from either ISO at the address below or ISO’s member body in the country of the

requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 255:2022(E)
Contents Page

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

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

1 Scope .................................................................................................................................................................... 1

2 Normative references .................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................... 1

4 Symbols and abbreviated terms ................................................................................................................. 1

5 Principle .............................................................................................................................................................. 2

6 Groove profile ................................................................................................................................................... 2

6.1 Specification ........................................................................................................................................................ 2

6.2 Inspection .............................................................................................................................................................4

6.2.1 Limit gauges ......................................................................................................................................... 4

6.2.2 Operation .............................................................................................................................................. 4

7 Groove spacing .............................................................................................................................................. 14

7.1 Specification ..................................................................................................................................................... 14

7.1.1 Groove spacings .............................................................................................................................. 14

7.1.2 Distance between edge of pulley and first group centre ................................................ 15

7.2 Inspection .......................................................................................................................................................... 15

8 Datum diameter ............................................................................................................................................ 17

8.1 Specifications ................................................................................................................................................... 17

8.1.1 Datum diameter .............................................................................................................................. 17

8.1.2 Checking balls or rods................................................................................................................... 17

8.2 Inspection .......................................................................................................................................................... 17

9 Run-out tolerances ....................................................................................................................................... 18

9.1 Specifications ................................................................................................................................................... 18

9.2 Inspection .......................................................................................................................................................... 18

Annex A (normative) Groove inspection with balls or rods for pulleys used with classical

and narrow V-belts as defined by ISO 4183 ........................................................................................ 20

Bibliography ................................................................................................................................................................. 21

© ISO 2022 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 255:2022(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.

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

different types of ISO documents should be noted. This document was drafted 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 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. Details of any

patent rights identified during the development of 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 information given for the convenience of users and does not

constitute an endorsement.

For an explanation onof the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the World

Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT)), see

www.iso.org/iso/foreword.htmlthe following URL: .

This document was prepared by Technical Committee ISO/TC 41, Pulleys and belts (including veebelts),

Subcommittee SC 1, Friction.

This third edition cancels and replaces the second edition (ISO 255:1990), which has been technically

revised.
The main changes are as follows:

— the normative references list has been updated, including adding of ISO 1081 (vocabulary);

— in Clause 2 and Bibliography, normative references are no longer dated;

— modifications made for clarification and to be in line with ISO drafting rules.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
iv © ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 255:2022(E)
Introduction

In drives using V-belts, the dimensions of the pulley grooves can be defined either on the basis of the

datum width or on the basis of the effective width. As a result, two systems for definition and description

of the dimensions of pulleys and belts have been developed. The two systems are independent of each

other.

For the geometrical inspection of grooves defined on the basis of the datum width, necessary tests to

ensure by mechanical means the conformity of a grooved pulley with standard specifications were

specified, but modern quick or serial checking procedures for grooved pulley production control were

not.

For user clarification, the interaction of this document with other relevant documents developed by

ISO/TC 41/SC 1 and ISO/TC 213 "“Dimensional and geometrical product specifications and verification"”

is given in Figure 1.
© ISO 2022 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/FDIS 255:2022(E)

Figure 1 — Interaction of this document with other relevant documents developed by

ISO/TC 41/SC 1 and ISO/TC 213
vi © ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/FDIS 255:2022(E)
Belt drives — Pulleys for V-belts (system based on datum
width) — Geometrical inspection of grooves
1 Scope

This document specifies the methods of checking the regularity of the grooves and pulleys for V-belts

specified in the system based on datum width. The grooved pulleys may be designed for use with classical

or narrow V-belts.

Inspection parameters and tolerances of grooved pulleys are covered by appropriate International

Standards.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 1081, Belt drives — V-belts and V-ribbed belts, and corresponding grooved pulleys — Vocabulary

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1081 apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
4 Symbols and abbreviated terms
For the purpose of this document, the symbols and abbreviat
...

INTERNATIONAL ISO
STANDARD 255
Third edition
Belt drives — Pulleys for V-belts
(system based on datum width) —
Geometrical inspection of grooves
Transmissions par courroies — Poulies à gorges pour courroies
trapézoïdales (système basé sur la largeur de référence) — Contrôle
géométrique des gorges
PROOF/ÉPREUVE
Reference number
ISO 255:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 255:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE © ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 255:2022(E)
Contents Page

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

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

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Symbols ......................................................................................................................................................................................................................... 1

5 Principle ........................................................................................................................................................................................................................ 2

6 Groove profile ......................................................................................................................................................................................................... 2

6.1 Specification ............................................................................................................................................................................................. 2

6.2 Inspection ................................................................................................................................................................................................... 2

6.2.1 Limit gauges............................................................................................................................................................................ 2

6.2.2 Operation .................................................................................................................................................................................. 3

7 Groove spacing ....................................................................................................................................................................................................... 7

7.1 Specification ............................................................................................................................................................................................. 7

7.1.1 Groove spacings .................................................................................................................................................................. 7

7.1.2 Distance between edge of pulley and first group centre ................................................................ 8

7.2 Inspection ................................................................................................................................................................................................... 8

8 Datum diameter ....................................................................................................................................................................................................9

8.1 Specifications ........................................................................................................................................................................................... 9

8.1.1 Datum diameter .................................................................................................................................................................. 9

8.1.2 Checking balls or rods ................................................................................................................................................... 9

8.2 Inspection ................................................................................................................................................................................................... 9

9 Run-out tolerances .........................................................................................................................................................................................10

9.1 Specifications ........................................................................................................................................................................................ 10

9.2 Inspection ................................................................................................................................................................................................ 10

Annex A (normative) Groove inspection with balls or rods for pulleys used with classical

and narrow V-belts as defined by ISO 4183 ..........................................................................................................................11

Bibliography .............................................................................................................................................................................................................................12

iii
© ISO 2022 – All rights reserved PROOF/ÉPREUVE
---------------------- Page: 3 ----------------------
ISO 255:2022(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.

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

different types of ISO documents should be noted. This document was drafted 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 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. Details of

any patent rights identified during the development of 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 information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 41, Pulleys and belts (including veebelts),

Subcommittee SC 1, Friction.

This third edition cancels and replaces the second edition (ISO 255:1990), which has been technically

revised.
The main changes are as follows:

— the normative references list has been updated, including adding of ISO 1081 (vocabulary);

— in Clause 2 and Bibliography, normative references are no longer dated;

— modifications made for clarification and to be in line with ISO drafting rules.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
PROOF/ÉPREUVE © ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 255:2022(E)
Introduction

In drives using V-belts, the dimensions of the pulley grooves can be defined either on the basis of the

datum width or on the basis of the effective width. As a result, two systems for definition and description

of the dimensions of pulleys and belts have been developed. The two systems are independent of each

other.

For the geometrical inspection of grooves defined on the basis of the datum width, necessary tests

to ensure by mechanical means the conformity of a grooved pulley with standard specifications were

specified, but modern quick or serial checking procedures for grooved pulley production control were

not.

For user clarification, the interaction of this document with other relevant documents developed by

ISO/TC 41/SC 1 and ISO/TC 213 “Dimensional and geometrical product specifications and verification”

is given in Figure 1.

Figure 1 — Interaction of this document with other relevant documents developed by

ISO/TC 41/SC 1 and ISO/TC 213
© ISO 2022 – All rights reserved PROOF/ÉPREUVE
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 255:2022(E)
Belt drives — Pulleys for V-belts (system based on datum
width) — Geometrical inspection of grooves
1 Scope

This document specifies the methods of checking the regularity of the grooves and pulleys for V-belt

...