Compact Cylinders

All three are built on the same ISO 21287 footprint but differ in action type: RA/191000 is single-acting, sprung-in — the spring pulls the rod in, air pressure extends it (Ø 20-63 mm); RA/192000 is double-acting, the industry baseline (Ø 20-125 mm, including the guided /N2, /N4, /N6 options, the /TM tandem, the /L4 locking unit, and the T high-temperature variants); RA/193000 is single-acting, sprung-out — the spring extends the rod, air pressure retracts it (Ø 20-63 mm, fail-safe extended position). Note: the single-acting variants are slightly longer than the double-acting equivalent to accommodate the spring.

The RA/192000 is available with three different guiding options when the rod must not rotate or must absorb side loads: /N2 = internal non-rotating piston rod for Ø 20-100 mm, no side-load capability; /N4 = internal guiding for Ø 20-100 mm, supports significant side loads (Ø 20-25 max stroke 80 mm; Ø 32-100 max stroke 100 mm); /N6 = external guiding assembly available only on Ø 25 and Ø 32 mm, standard strokes 25, 50, 75, 100 mm. The EX (ATEX) version supports only /N2 and /N4, /N6 is not available. To combine with magnetic piston, add M to the code: e.g. RA/192040/N4/M = Ø 40 mm with internal guiding and magnetic piston.

Neither, on their own. M/50100 (single-acting, spring return): the spring pulls the rod back as soon as air is lost — so the clamp releases (fail-open behaviour). M/50200 (double-acting): the clamp is held by active air pressure on one side; when air is lost, the rod becomes free, it does NOT stay locked. If mechanical lock-on-pressure-loss is required, do not choose M/50100 or M/50200 — choose the RA/192000/L4 ISO compact with passive spring-locking unit (4-10 bar releases the lock, signal loss engages the spring-driven mechanical lock). Catalogue configuration: RA/192xxx/L4 (Ø 32-125 mm) — the Norgren answer for fail-locked clamping in this category.

Standard (e.g. PRA/802000): full-length housing, full stroke, full options. Short-stroke: same housing diameter as standard, just a short stroke (e.g. 25 mm). Compact (RA/191000 / RA/192000 / RA/193000 to ISO 21287): housing roughly 60% of standard length per equivalent stroke, optimised for tight installations. Pick compact when housing length matters; short-stroke when you only need limited motion in a standard mount.

No — different standards for different cylinder types. ISO 6431 / ISO 15552 governs profile cylinders (RA/8000, PRA/802000) — full-length tie-rod / profile-extrusion cylinders. ISO 21287 governs compact cylinders — Ø 20-100 mm short-housing format (some manufacturers, including Norgren on the RA/192000, extend to Ø 125 mm). Typically rated to 10 bar (1000 kPa) max operating pressure, with most modern manufacturers shipping a magnetic piston for position sensing. The two standards share some thread sizes for ports and mountings but the body dimensions are different. Always check the spec the application calls for.

Clamping is a positioning operation, not a motion operation — you only need enough stroke to engage the workpiece against a stop. 4-25 mm stroke is plenty for typical fixturing (workpiece tolerance + clearance + engagement). Longer strokes mean more housing length, defeating the purpose of a compact clamping cylinder.