ISO 22705-3:2024

Overview

ISO 22705-3:2024 outlines standardized measurement and test methods for the general characteristics of cold formed cylindrical helical torsion springs made from round wire, with dynamic testing excluded. This international standard provides guidance for manufacturers, quality inspectors, and end-users on how to accurately assess and ensure the consistency of essential spring dimensions and properties. By adhering to these guidelines, organizations can achieve higher product reliability and better alignment with global best practices in spring manufacturing and quality control.

Key Topics

This ISO standard covers several important aspects related to the measurement and testing of cold formed cylindrical helical torsion springs, including:

• Body length (LB): Defined as the axial length of the spring body, measured without any applied load and excluding the legs.
• Outside diameter (De) and Inside diameter (Di): Procedures for obtaining these measurements at multiple positions along the spring to account for possible variances.
• Spring leg length (l): Methods for determining leg length even when torsion springs have multiple leg segments.
• Number of coils (n) and coil direction: Enumeration and definition of active coils, as well as specification of coil winding direction.
• Other Characteristics: Measurement of bending radius on legs, angle of bend (φ), spring pitch (p), coil spacing (u), spring torque (M), free angle (γ₀), and detection of shear-off burrs.

Measurement Equipment:

• Recommended devices include micrometers, callipers, height and dial gauges, optical systems, and “GO/NO-GO” gauges for both variable and attributive testing.

Measurement Conditions:

• Measurements are performed at ambient temperature and in a normal workshop environment unless otherwise negotiated between customer and manufacturer.
• Proper qualification and training of personnel undertaking these measurements are required.

Applications

ISO 22705-3:2024 is an essential standard for a range of industries that use torsion springs, such as:

• Automotive: Ensuring that safety-critical components like hinges and pedal assemblies meet dimensional and functional requirements.
• Industrial machinery: Supporting the production and maintenance of accurate, reliable spring-loaded mechanisms.
• Consumer goods: Controlling quality in products like clipboards, clothespins, and window locks that rely on torsion spring action.
• Manufacturing and quality assurance: Standardizing production checks, incoming goods inspection, and supplier audits for torsion springs.

Applying the measurement and testing techniques specified in this standard helps reduce product failures, improve spring performance, and maintain compliance with international market requirements.

Related Standards

For a complete approach to spring measurement and compliance, organizations may also refer to the following related standards:

• ISO 22705 Series: Covers other types of springs and related testing parameters.
• ISO 26909: Provides terminology for springs and related components.
• ISO 3611: Specifies requirements for micrometers used in measurement.
• ISO 13385-1: Pertains to callipers for length measurement.

Practical Value

Implementing ISO 22705-3:2024 supports consistent and reproducible assessment of cylindrical helical torsion springs, improving product quality, customer satisfaction, and process efficiency. The standard streamlines communication between suppliers and manufacturers and ensures alignment with modern requirements for spring testing and qualification.

By integrating these measurement and test procedures, organizations gain a systematic, globally recognized approach to quality assurance in spring manufacturing, underpinning reliable performance in the end application.

Keywords: ISO 22705-3:2024, cold formed torsion springs, cylindrical helical springs, spring measurement, spring test parameters, industrial spring standards, quality control, technical standardization.