Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X250S
The AirTAC SAILF Front Locking Pneumatic Cylinder SAILF125X250S is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 250mm 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.
- BoreØ125 mm
- Stroke250 mm
- Port sizeG1/2
- Lock positionFront cover
- Rod threadM27×2
- UnlockAir + manual
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X250S
The AirTAC SAILF125X250-S 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 carbon steel rod, securely holding the load at the extended stroke end without requiring live pressure. In the 125mm bore class, it generates 6136N of push force and 5734N of pull force at 0.5 MPa, making it well-suited for heavy vertical lifting tasks.
This model includes a magnetic piston (-S) for position detection via AirTAC CMSE reed switches or DMSE solid-state electronic sensors. A notable design detail is that the variable air cushion at the locker end is 24mm, intentionally shorter than the 40mm cushion at the free end. The cushion decelerates the piston near stroke termination, but only the mechanical lock provides true static load holding upon power loss.
Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X250S Technical Specifications
| Model | Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X250S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 250 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.
How the Lock Holds
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.
Theoretical Output Force (Ø125mm)
| 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.
Where the Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X250S Is Used
Vertical Lift Holding
Secures elevated heavy loads in the extended position automatically upon air pressure loss, preventing sudden drops in lifting rigs.
Safety Gate Lock
Maintains a protective gate fully extended and locked open during machine operation, releasing only via controlled air release.
End-of-Stroke Clamp
Holds a heavy workpiece firmly at the extended stroke terminal without consuming continuous compressed air during machining cycles.
Is the Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X250S the Right Lock Cylinder?
Select this 125mm bore when an application demands robust end-of-stroke holding power that a standard SAI cylinder cannot provide. If your thrust requirements are lower, stepping down to a 100mm bore reduces the push force to 3927N at 0.5 MPa. Choose this SAILF configuration specifically when the load must be secured in the extended rod-out position; conversely, select a SAILB variant if the retracted position must be held. For applications requiring the rod to be clamped at an arbitrary mid-stroke point rather than a stroke terminal, the BSAI clamp-lock cylinder is the correct alternative.
When integrating this cylinder, remember the lock is a static holding device that engages only after the piston stops, not a dynamic brake for a moving rod. Valve selection is critical: never use a fast-exhaust valve, as back-pressure on the locker side can unintentionally release the lock, and always utilize an independent-exhaust solenoid valve. If human safety depends on the load remaining extended, add an independent safety measure. For replacement matching, verify the 250mm stroke, front locker position, 1/2 PT port thread, and the -S magnet. Given the 250mm stroke, ensure proper guiding to mitigate side-load wear.
Quick checklist
- ✓ Hold needed at the extended (rod-out) end?
- ✓ Or lock anywhere → use BSAI
- ✓ Independent-exhaust valve fitted
- ✓ Port/thread type (PT/G)
- ✓ Extra safety measure for people
Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X250S FAQ
At a 0.5 MPa operating pressure, this 125mm bore cylinder provides 6136N of push force and 5734N of pull force. The maximum operating pressure is 1.0 MPa.
The lock is spring-applied and air-released, located in the front cover to hold the rod securely at the extended stroke end. It engages statically after the cylinder stops and is released automatically by supplying air to the release port or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
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