The AirTAC Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X25 is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 25mm stroke and a built-in spring-applied, air-released mechanical lock in the front cover — it holds the load at the extended (rod-out) stroke end even when air is lost.
The AirTAC SAILF125X25 is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the front cover. Because the lock is spring-applied and air-released, cutting the release air drives a lock pin into the rod, securely holding the load at the extended stroke end without relying on live pressure. In the 125mm bore class, this actuator generates a substantial 6136N of push force and 5734N of pull force at 0.5 MPa, making it well-suited for heavy-duty holding tasks.
This model features a carbon steel rod and PT tapered port threads. To accommodate the locking hardware, the variable air cushion at the locker end is 24mm, which is intentionally shorter than the 40mm cushion found on the non-locking end. The cylinder operates at speeds between 30 and 500 mm/s, and because no magnet is specified, it will require an external sensor setup if position detection is needed.
| Model | Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X25 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 25 mm |
| Acting type | Double acting, with lock |
| Port size | G1/2 |
| Rod thread | M27×2 |
| Lock type | Spring-applied, air-released (front cover) |
|---|---|
| Unlock | Automatic (air) & manual |
| Operating pressure | 0.15 – 1.0 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Cushion | Adjustable (40 mm free end / 24 mm lock end) |
| Max stroke | Up to 1500 mm |
Specifications follow the official AirTAC SAIL datasheet (ISO 15552). Confirm against the product label before installation. Port options: PT / G.
The lock is spring-applied and air-released: a spring drives a lock pin into the rod when the release air is removed, so the load is held at the extended (rod-out) stroke end without live pressure. Supply air to the release port to unlock automatically, or use the manual release lever.
The lock engages only when the piston reaches the stroke terminal on the front-cover side — it is a static end-of-stroke hold, not a mid-stroke clamp and not a moving-rod brake. For locking at any position along the stroke, choose a BSAI clamp-lock instead.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
Cylinder thrust is separate from the lock's holding capability. Actual usable force is lower than theoretical due to friction and back-pressure — size with a margin.
Secures heavy elevated loads in the extended position instantly upon air pressure loss, preventing sudden drops in lifting rigs.
Keeps safety gates and heavy barriers locked in the open, extended position during a pneumatic or electrical supply failure.
Maintains high-force clamping pressure mechanically at the fully extended stroke end without consuming continuous air supply.
Choose this 125mm bore when a 100mm bore (providing 3927N push at 0.5 MPa) is insufficient for your load, or step down if the 80mm bore (2513N) is already adequate. Select the SAILF configuration specifically when the load must be secured in the extended, rod-out position, whereas SAILB holds the retracted position. If your application requires clamping at an arbitrary mid-stroke point rather than the stroke terminal, the BSAI clamp-lock cylinder is the correct alternative.
Remember that this is a static holding lock that engages only after the cylinder has stopped, not a dynamic brake for a moving rod. Valve selection is critical: never use a fast-exhaust valve with this unit, as back-pressure on the locker side can inadvertently release the lock; always use an independent-exhaust solenoid valve. For any application where human safety depends on the load remaining extended, add an independent mechanical safety measure. To replace this unit, match the 125mm bore, 25mm stroke, front locker position, PT port threads, and standard carbon steel rod.
Quick checklist
At an operating pressure of 0.5 MPa, the 125mm bore provides a push force of 6136N and a pull force of 5734N. If operated at 0.7 MPa, the push force increases to 8590N.
The lock is spring-applied and air-released, meaning it engages automatically to hold the rod at the extended stroke end when release air is cut off. You can unlock it by supplying air to the release port or by using the manual release lever.
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