Overview
SIST EN ISO 22705-3:2025 defines standardized measurement and test methods for the general characteristics of cold formed cylindrical helical torsion springs made from round wire. This European standard, developed by CEN and based on ISO 22705-3:2024, specifically excludes dynamic testing. The guidance provided applies to torsion springs fabricated at ambient temperature, covering essential geometric and physical parameters for consistent product quality and performance. This standard assures that manufacturers, suppliers, and quality professionals uniformly evaluate cold formed helical torsion springs using proven, industry-recognized procedures.
Key Topics
The document details the following key parameters and measurement methods for cold formed cylindrical helical torsion springs:
- Body length (axial length excluding spring legs)
- Outside diameter (maximum diameter of spring body, not including legs)
- Inside diameter (minimum diameter across spring coils, excluding leg interference)
- Spring leg length (length of torsion spring arms)
- Number of coils and coil direction (count and orientation, crucial for performance)
- Bending radius and angle of bends on legs
- Spring pitch and coil spacing (distance between coils)
- Spring torque (torque generated under load)
- Free angle (angle formed by spring legs in the unloaded state)
- Shear-off burr presence (assessment for manufacturing burrs)
- Applicable measuring equipment: including micrometers, callipers, gauges, and optical instruments
- Environmental conditions for testing: typically ambient temperature in normal workshop settings
- Qualifications for personnel: requirements for training and competency in measurement techniques
All parameters are measured or tested following standardized procedures, ensuring repeatability and accuracy in results. Both variable (precise measurements) and attributive (go/no-go tools) methods are included, with test locations and specific equipment referenced to support consistency.
Applications
Implementing SIST EN ISO 22705-3:2025 supports a wide range of industrial and manufacturing applications involving cold formed torsion springs, such as:
- Automotive and transport: Ensuring consistent torsion spring quality for vehicle components
- Mechanical engineering: Precise measurement of springs for reliable performance in assemblies
- Consumer products and electronics: Quality control of torsion springs in devices and mechanisms
- Supplier and manufacturing quality assurance: Standardized acceptance criteria and incoming inspection
- Compliance and certification: Demonstrating conformity to recognized measurement and testing standards
By following this standard, organizations improve traceability, support procurement specification, and enhance end-product reliability.
Related Standards
Professionals involved with cold formed cylindrical helical torsion springs may also find the following standards relevant:
- ISO 22705 series: Additional parts cover other types of technical springs and parameters
- ISO 26909: Terminology and classification of springs
- ISO 3611: Micrometers for external measurement - requirements and test methods
- ISO 13385-1: Callipers - requirements for digital and dial callipers
- EN ISO 22705-1 & EN ISO 22705-2: Measurement and testing of other cold formed or hot formed technical springs
For optimal application, manufacturers and testers should reference the entire ISO 22705 series and align their quality management systems with this and related standards.
Keywords: SIST EN ISO 22705-3:2025, cold formed cylindrical helical torsion springs, spring measurement, spring testing, spring parameters, round wire spring, torsion spring standard, CEN, ISO 22705-3:2024, quality assurance, spring manufacturing standards.