ISO 21287:2004

Overview

ISO 21287:2004 defines a metric series of single‑rod pneumatic compact cylinders for pneumatic fluid power systems, rated to a maximum working pressure of 1 000 kPa (10 bar). The standard covers compact cylinder bores from 20 mm to 100 mm, available with or without magnetic piston function. These cylinders are intended for installations where standard cylinder mounting envelopes are too large and where adjustable cushioning is not required.

Key topics and requirements

• Bore sizes covered: 20, 25, 32, 40, 50, 63, 80, 100 mm (in accordance with ISO 3320).
• Maximum working pressure: 1 000 kPa (10 bar).
• Stroke: Nominal strokes follow ISO 4393; maximum recommended stroke length is 500 mm. Nominal stroke tolerances are specified in the standard.
• No adjustable cushioning: The series is deliberately specified without adjustable end‑stroke cushioning; appropriate only for systems that tolerate fixed end conditions.
• Mounting types and dimensions: Includes mounting types per ISO 6099 such as:
  • MP4 - cap, detachable plain eyes
  • MF1 - head, rectangular flange
  • MF2 - cap, rectangular flange
  • MS1 - end angles Detailed basic and mounting dimensions, tolerances and theoretical reference points (TRP) are defined.
• Interchangeability: Cylinders with 20 mm and 25 mm bores use end cover mountings per ISO 21287; bores 32–100 mm can use end cover mountings per ISO 15552.
• Rod end fittings: Piston rod mountings conform to ISO 8139 and ISO 8140.
• Connections and ports: References to port and stud end dimensions per ISO 16030.
• Identification statement: The standard provides a recommended compliance statement for catalogs and test reports.

Applications and users

ISO 21287 compact cylinders are suited to space‑constrained pneumatic systems and where simple, robust linear actuation is required without adjustable cushioning. Typical applications:

• Industrial automation (pick‑and‑place, indexing)
• Packaging and material handling
• Clamp, ejector and positioning devices
• Machine tools and assembly equipment

Primary users:

• Cylinder manufacturers and OEMs specifying interchangeability
• Mechanical and pneumatic system designers
• Procurement and quality engineers validating component dimensions
• Maintenance and service teams replacing parts to standard dimensions

Related standards

Normative references and complementary standards include:

• ISO 3320 (bore/piston rod metric series)
• ISO 4393 (piston stroke series)
• ISO 6099 (mounting identification)
• ISO 15552 (detachable mountings for bores 32–320 mm)
• ISO 8139 / ISO 8140 (rod end mounting dimensions)
• ISO 16030 (ports and stud ends)

Using ISO 21287:2004 helps ensure dimensional interchangeability, clear mounting definitions, and consistent performance expectations for compact pneumatic cylinders at 10 bar.