ISO 22705-2:2023

Overview

ISO 22705-2:2023 - Springs - Measurement and test parameters - Part 2: Cold formed cylindrical helical extension springs specifies standardized measurement and test methods for general characteristics of cold‑formed cylindrical helical extension springs made from round wire. The document focuses on dimensional and static test parameters and excludes dynamic testing. It provides guidance on environmental conditions, required qualifications, measuring equipment and detailed methods for each characteristic.

Key topics and technical requirements

The standard systematically defines how to measure and test the principal features of cold‑formed extension springs. Key topics include:

• Environmental and personnel requirements – conditions for measurements and qualifications of test personnel.
• Guiding and supporting device geometries – recommended fixtures and supports for accurate measurement.
• Measuring and testing equipment – instruments and calibration considerations for static tests.
• Dimensional and mechanical parameters with defined measurement methods, such as:
  • Free length (L0) and body length (LB)
  • Hook/hook‑loop dimensions (hook length LH, hook opening m, loop/hook position)
  • Outside and inside diameter (De, Di)
  • Total and active number of coils, coil direction
  • Bending radius and pitch (distance between coils)
  • Spring load (F) - static load measurements and test conditions
  • Shear‑off burr inspection criteria
• Test location and acceptance points - where on the product to measure each parameter.
• Informative annexes for calculation methods, including spring rate, initial tension force, and common types of hooks.

All topics are presented with the type of characteristic, required equipment, test conditions and precise measurement methods to ensure repeatability and comparability.

Practical applications

ISO 22705-2:2023 is intended to support consistent quality control, product specification and supplier acceptance for cold‑formed cylindrical helical extension springs. Typical uses include:

• Production quality control in spring manufacturing
• Incoming inspection and supplier qualification
• Component verification during product design and prototyping
• Compliance documentation for purchasing and procurement specifications
• Laboratory static testing and reporting

Industries that commonly rely on these standards include automotive, industrial machinery, appliances, consumer products and any sector using extension springs where dimensional accuracy and static performance matter.

Who should use this standard

• Spring manufacturers and production engineers
• Quality assurance and inspection personnel
• Test laboratories and calibration facilities
• Design engineers and product developers specifying springs
• Procurement and supplier quality managers

Related standards

Use ISO 22705-2:2023 alongside other ISO standards on spring design and testing practices and any industry‑specific requirements to ensure comprehensive conformity and interoperability.