Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300
The AirTAC Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300 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
- 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 SAILF125X300
The AirTAC SAILF125X300 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock housed in the front cover. Because the lock sits forward, it engages only when the piston reaches the extended stroke end, rigidly holding the rod and load in the out position. Operating at 0.5 MPa, this 125 mm bore generates 6136 N of push thrust and 5734 N of pull thrust, making it well-suited for heavy vertical lifting tasks. The standard carbon steel rod provides durable service in demanding industrial environments.
Unlike a plain SAI cylinder, the SAIL lock maintains a static hold without requiring continuous air pressure, which is essential for power-loss safety. The variable air cushion at the locker end is 24 mm, intentionally shorter than the 40 mm cushion on the free end to accommodate the locking hardware. For position feedback, adding a -S magnet enables tracking via AirTAC CMSE reed or DMSE electronic solid-state sensors. Remember that this lock is a static holding device; it engages after the cylinder stops and is not a dynamic brake for a moving rod.
Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300 Technical Specifications
| Model | Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300 |
|---|---|
| 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 SAILF125X300 Is Used
Vertical Lift Safety
Holds heavy lifted loads securely at the extended stroke end, preventing sudden drops if air pressure is lost during operation.
Clamp and Hold
Maintains constant clamping pressure on large workpieces at the rod-out position without consuming continuous compressed air.
Gate and Guard Locking
Secures safety gates and heavy industrial barriers in the open, extended position until the release air is actively supplied.
Is the Airtac SAILF Front Locking Pneumatic Cylinder SAILF125X300 the Right Lock Cylinder?
Select this 125 mm bore model when an application requires holding a heavy load securely at the fully extended position; if your process only needs to hold the retracted rod-in position, choose the SAILB125X300 instead. If the mechanism must lock at an arbitrary mid-stroke point rather than a stroke end, the AirTAC BSAI clamp-lock cylinder is the correct choice. The SAILF125X300 operates at speeds of 30-500 mm/s, appropriate for larger bores. When matching replacements, verify the 300 mm stroke, front locker position, 1/2 PT port threads, and the specific mounting style (Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, or TCM2).
Because the 300 mm stroke increases the moment arm on the rod, ensure external guide shafts are used to prevent excessive side-loading on the seals. The lock holds the load statically at the extended end, but back-pressure on the locker side can accidentally release the mechanism; therefore, do not use a fast-exhaust valve and always control the circuit with an independent-exhaust solenoid valve. If human safety depends on the load remaining extended, add an independent mechanical safety measure beyond the pneumatic lock.
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 SAILF125X300 FAQ
At a standard 0.5 MPa operating pressure, the 125 mm bore provides 6136 N of push force and 5734 N of pull force. At the maximum 1.0 MPa pressure, it delivers up to 1251 kgf of push force.
The lock is spring-applied and air-released, engaging automatically when the piston reaches the extended stroke end to hold the load statically without live pressure. To unlock it, you supply air to the release port for automatic release or use the manual release lever.
Related AirTAC Lock & Standard Cylinders
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