Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300S
The AirTAC Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300S is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 300mm 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
- Stroke300 mm
- Port sizeG1/2
- Lock positionFront cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300S
The AirTAC SAILF125X300-S is a double-acting ISO 15552 profile cylinder equipped with a magnetic piston and a built-in mechanical lock housed in the front cover. Because this is a SAILF variant, the spring-applied, air-released lock engages automatically when the piston reaches the extended stroke end, ensuring the rod remains securely held outward without requiring continuous live air pressure. In the 125mm bore class, it generates a substantial 6136N push force and 5734N pull force at 0.5 MPa, making it well-suited for heavy-duty holding tasks.
The lock functions strictly as a static holding device, engaging only after the cylinder has stopped at the stroke terminal, rather than acting as a dynamic brake for a moving rod. It is important to note that the variable air cushion at the front locker end is 24mm, which is shorter than the 40mm cushion found at the rear free end. For position detection, the included magnet is fully compatible with AirTAC CMSE reed switches and DMSE solid-state sensors.
Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300S Technical Specifications
| Model | Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 300 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 SAILF125X300S Is Used
Vertical Load Hold
Maintains heavy lifted loads in the extended position during a power loss, using the front mechanical lock to prevent gravity-driven drops.
Extended Clamp Hold
Secures a workpiece or gate at the full rod-out stroke end without consuming continuous compressed air, reducing energy costs.
Safety Gate Hold
Keeps safety barriers and heavy doors firmly open at the extended terminal until an air signal releases the lock.
Is the Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300S the Right Lock Cylinder?
Choose this 125mm bore model when an application demands high load-holding capacity at the extended stroke end, as stepping down to an 80mm bore would reduce the push force at 0.5 MPa to just 2513N. If the mechanical lock must clamp the rod at an arbitrary mid-stroke position rather than at the extended terminal, the AirTAC BSAI clamp-lock cylinder is the correct alternative. Always remember that the SAIL lock is a static hold, not a moving-rod brake, and if human safety depends on the load remaining extended, an independent safety measure must be added.
When integrating this cylinder, avoid using a fast-exhaust valve, as back-pressure on the locker side can inadvertently release the lock; instead, use an independent-exhaust solenoid valve. Because the 300mm stroke increases the risk of mechanical deflection, use a guide rail to manage side loads and prevent rod damage. To replace this unit, match the 125mm bore, 300mm stroke, front locker position, PT port threads, and the -S magnet specification.
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 SAILF125X300S FAQ
At an operating pressure of 0.5 MPa, this 125mm bore cylinder provides a push force of 6136N and a pull force of 5734N. At 0.7 MPa, the push force increases to 8590N.
The spring-applied, air-released lock engages when the piston reaches the extended stroke end. It holds the rod statically without live pressure. To unlock, supply air to the release port or use the manual release lever. It does not clamp at mid-stroke.
Related AirTAC Lock & Standard Cylinders
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