ISO 11901-2:2025

Overview - ISO 11901-2:2025 (Gas springs mounting accessories)

ISO 11901-2:2025 specifies the geometrical and material requirements for mounting accessories used with gas springs in press tooling. The fourth edition defines dimensions in millimetres for mounting base plates, two‑part mounting clamps, flange mounts (cylindrical, square and rectangular) and front end supports intended to be used with gas springs manufactured in accordance with ISO 11901‑1, ISO 11901‑3 and ISO 11901‑4. The standard also gives material guidance and a rule for product designation.

Key topics and technical requirements

• Dimensional specifications: Detailed figures and tabulated dimensions for accessory types A, B, C, D and E (e.g., A1, A2, B, C1/C2, D1/D2, E). Sizes cover a wide range of gas spring cylinder diameters shown in the tables (examples in the standard range from around 19 mm up to 195 mm).
• Tolerances: General tolerances are specified as class m in accordance with ISO 2768‑1; individual dimensions reference the applicable tolerance class.
• Material: Mounting accessories shall be made from steel S355C (ISO 630‑2) or an alternative material with equivalent mechanical characteristics.
• Assembly details: Notes and figures describe flange halves, plain rings and assembly screws, and indicate how flange mounts and front end supports are mounted to gas springs.
• Designation rules: A standard naming convention is specified (example: “Mounting base plate ISO 11901‑2 – A1 – 50” for a type A1 plate for a 50 mm cylinder).

Practical applications

• Ensures interchangeability and compatibility of mounting accessories across manufacturers and toolmakers.
• Used in the design, manufacture and maintenance of press tools, jigs and fixtures that incorporate gas springs for force control, damping or return actions.
• Facilitates procurement and quality control by providing unambiguous dimensions and material specifications for suppliers and purchasers.

Who should use this standard

• Tool designers and press-tool manufacturers
• Gas spring and accessory manufacturers
• Maintenance engineers and toolroom personnel
• Quality and compliance teams specifying components for industrial presses

Related standards

• ISO 11901‑1: General specifications for gas springs for pressing tools
• ISO 11901‑3 and ISO 11901‑4: Variants with increased spring force or compact/build‑height considerations
• ISO 630‑2 (structural steels) and ISO 2768‑1 (general tolerances)

Keywords: ISO 11901‑2, gas springs, mounting accessories, mounting base plates, flange mounts, mounting clamps, front end supports, S355C, press tools.