SIST EN ISO 22705-3:2025

SLOVENSKI STANDARD
01-december-2025
Vzmeti - Merilni in preskusni parametri - 3. del: Hladno oblikovane cilindrične,
vijačne, torzijske tlačne vzmeti (ISO 22705-3:2024)
Springs - Measurement and test parameters - Part 3: Cold formed cylindrical helical
torsion springs (ISO 22705-3:2024)
Federn - Mess- und Prüfgrößen - Teil 3: Kaltgeformte zylindrische Schraubenfedern (ISO
22705-3:2024)
Ressort - Mesures et paramètres d'essai - Partie 3: Ressorts à torsion cylindrique,
enroulés à froid (ISO 22705-3:2024)
Ta slovenski standard je istoveten z: EN ISO 22705-3:2025
ICS:
21.160 Vzmeti Springs
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22705-3
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2025
EUROPÄISCHE NORM
ICS 21.160
English Version
Springs - Measurement and test parameters - Part 3: Cold
formed cylindrical helical torsion springs (ISO 22705-
3:2024)
Ressorts - Mesures et paramètres d'essai - Partie 3: Federn - Mess- und Prüfgrößen - Teil 3: Kaltgeformte
Ressorts hélicoïdaux de torsion cylindriques formés à zylindrische Schraubenfedern (ISO 22705-3:2024)
froid (ISO 22705-3:2024)
This European Standard was approved by CEN on 29 September 2025.

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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22705-3:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 22705-3:2024 has been prepared by Technical Committee ISO/TC 227 "Springs” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 22705-3:2025
by Technical Committee CEN/TC 407 “Technical springs” the secretariat of which is held by AFNOR.
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 April 2026, and conflicting national standards shall be
withdrawn at the latest by April 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 22705-3:2024 has been approved by CEN as EN ISO 22705-3:2025 without any
modification.
International
Standard
ISO 22705-3
First edition
Springs — Measurement and test
2024-04
parameters —
Part 3:
Cold formed cylindrical helical
torsion springs
Ressort — Mesures et paramètres d'essai —
Partie 3: Ressorts à torsion cylindrique, enroulés à froid
Reference number
ISO 22705-3:2024(en) © ISO 2024

ISO 22705-3:2024(en)
© ISO 2024
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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 22705-3:2024(en)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions .1
3.2 Symbols and abbreviated terms .2
4 Environmental conditions . 4
5 Qualifications of the person(s) performing the work . 5
6 Geometries of guiding and supporting devices . 5
7 Measuring and testing equipment . 5
8 Measurement and test parameter for technical cold formed cylindrical torsion springs . 5
8.1 Body length (L ) .5
B
8.1.1 General .5
8.1.2 Type of characteristic .5
8.1.3 Measuring and/or testing equipment .5
8.1.4 Conditions of measurement and testing .6
8.1.5 Method of measurement and testing .6
8.1.6 Test location on the product.7
8.2 Outside diameter (D ).7
e
8.2.1 General .7
8.2.2 Type of characteristic .8
8.2.3 Measurement and/or testing equipment .8
8.2.4 Conditions of measurement and testing .8
8.2.5 Method of measurement and testing .8
8.2.6 Test location on the product.10
8.3 Inside diameter (D ) .10
i
8.3.1 General .10
8.3.2 Type of characteristic .11
8.3.3 Measurement and/or testing equipment .11
8.3.4 Conditions of measurement and testing .11
8.3.5 Method of measurement and testing .11
8.3.6 Test location on the product. 13
8.4 Spring leg length (l) . .14
8.4.1 General .14
8.4.2 Type of characteristic .14
8.4.3 Measurement and/or testing equipment .14
8.4.4 Conditions of measurement and testing . 15
8.4.5 Method of measurement and testing . 15
8.4.6 Test location on the product. 15
8.5 Number of coils (n) and coil direction . 15
8.5.1 General . 15
8.5.2 Type of characteristic .16
8.5.3 Measurement and/or testing equipment .16
8.5.4 Conditions of measurement and testing .16
8.5.5 Method of measurement and testing .16
8.5.6 Test location on the product.17
8.6 Bending radius on legs (r) .17
8.6.1 General .17
8.6.2 Type of characteristic .17
8.6.3 Measurement and/or testing equipment .17
8.6.4 Conditions of measurement and testing .18
8.6.5 Method of measurement and testing .18

iii
ISO 22705-3:2024(en)
8.6.6 Test location on the product.18
8.7 Angle of bend on legs (φ) .18
8.7.1 General .18
8.7.2 Type of characteristic .18
8.7.3 Measurement and/or testing equipment .19
8.7.4 Conditions of measurement and testing .19
8.7.5 Method of measurement and testing .19
8.7.6 Test location on the product. 20
8.8 Spring pitch (p)/distance between the coils (u) . 20
8.8.1 General . 20
8.8.2 Type of characteristic . 20
8.8.3 Measurement and/or testing equipment .21
8.8.4 Conditions of measurement and testing .21
8.8.5 Method of measurement and testing .21
8.8.6 Test location on the product.21
8.9 Spring torque (M) . .21
8.9.1 General .21
8.9.2 Type of characteristic .21
8.9.3 Measurement equipment . 22
8.9.4 Conditions of measurement . . 22
8.9.5 Method of measurement . 22
8.9.6 Test location on the product. 23
8.10 Free angle (γγ ) .
8.10.1 General . 23
8.10.2 Type of characteristic . 23
8.10.3 Measurement and/or testing equipment .24
8.10.4 Conditions of measurement and testing .24
8.10.5 Method of measurement and testing .24
8.10.6 Test location on the product.24
8.11 Shear-off burr .24
8.11.1 General .24
8.11.2 Type of characteristic .24
8.11.3 Test equipment . 25
8.11.4 Conditions of testing . 25
8.11.5 Method of testing . 25
8.11.6 Test location on the product. 25
Annex A (informative) Calculation of spring rate R .26
M
Annex B (informative) Type of legs .27
Annex C (informative) Measurement of the length of leg l .28
Annex D (informative) Offset of leg c .29
Bibliography .30

iv
ISO 22705-3:2024(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 http://www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 227, Springs.
A list of all parts in the ISO 22705 series can be found on the ISO website.
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.

v
International Standard ISO 22705-3:2024(en)
Springs — Measurement and test parameters —
Part 3:
Cold formed cylindrical helical torsion springs
1 Scope
This document specifies the measurement and test methods for general characteristics of cold formed
cylindrical helical torsion springs made from round wire, excluding dynamic testing.
2 Normative references
There are no normative references in this document.
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions 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/
3.1.1
spring
mechanical device designed to store energy when deflected and to return the equivalent amount of energy
when released
[SOURCE: ISO 26909:2009, 1.1]
3.1.2
torsion spring
spring that offers resistance to a twisting moment around the longitudinal axis of the spring
[SOURCE: ISO 26909:2009, 1.4]
3.1.3
coil spring
coil-shaped spring
[SOURCE: ISO 26909:2009, 3.11]
3.1.4
helical torsion spring
torsion spring normally made of wire of circular cross-section wound around an axis and with ends suitable
for transmitting a twisting moment
[SOURCE: ISO 26909:2009, 3.14]

ISO 22705-3:2024(en)
3.1.5
cold formed spring
spring formed at ambient temperature
[SOURCE: ISO 26909:2009, 1.12]
3.1.6
free angle
relative angle between both ends of a helical torsion spring when no load is applied
[SOURCE: ISO 26909:2009, 5.63]
3.1.7
torsional moment
torque
moment generated around the axis when external force is applied to a helical torsion spring
[SOURCE: ISO 26909:2009, 5.11]
3.1.8
spring characteristics
relationship between the load applied to a spring and the deflection caused by the load
[SOURCE: ISO 26909:2009, 5.1]
3.1.9
force
force exerted on or by a spring in order to reproduce or modify motion, or to maintain a system of forces in
equilibrium
[SOURCE: ISO 26909:2009, 5.2]
3.1.10
test parameter
parameter with a tolerance for which there is an immediate conclusion after test (OK or not OK)
Note 1 to entry: Test can be done without measurement (i.e. with go/no-go gauges)
3.2 Symbols and abbreviated terms
Table 1 includes the symbols and abbreviated terms used throughout this document.
Table 1 — Symbols and abbreviated terms
Symbols Units Designations
c mm offset of leg (see Annex D)
D mm outside diameter of spring
e
D mm inside diameter of spring
i
d mm diameter of wire
d mm maximum diameter of wire
max
d mm wire diameter after coiling
wire
d mm diameter of loading pins
R
L mm body length in axis direction (excluding legs) when unloaded
B
l mm length of leg (without considering working effect) see Annex C
l , l , . mm length of leg segments (without considering working effect)
1 2
l mm effective working length of leg
w
l , l , . mm effective working length of legs
w,1 w,2
ISO 22705-3:2024(en)
TTaabbllee 11 ((ccoonnttiinnueuedd))
Symbols Units Designations
M N·mm spring torque or moment
M N·mm spring torque for the maximum test torsional angle and related leg length
n
M , M , . N·mm spring torques for the specified spring loads
1 2
n - number of coils
p mm spring pitch
MM-
ΔM
N·mm/rad,
R ==
angular spring rate (see Annex A)
M
N·mm/degree
Δαα -α
r mm bending radius
r , r , . mm inner bend radius on legs
1 2
r mm effective working radius
w
r , r , . mm effective working radius of legs
w,1 w,2
u mm distance between the coils
α rad, degree angular deflection of spring (stroke) between two positions α , α
h 1 2
α rad, degree maximum permissible test torsional angle
n
...