Airtac SAILB Rear Lock Cylinder SAILB125X25
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X25 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 back cover — it holds the load at the retracted (rod-in) stroke end even when air is lost.
- BoreØ125 mm
- Stroke25 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X25
The AirTAC SAILB125X25 is a double-acting ISO 15552 profile cylinder equipped with a spring-applied, air-released mechanical lock housed in the back cover. This built-in lock engages automatically when the piston reaches the retracted stroke end, ensuring your load remains securely held without requiring continuous live air pressure. At 0.5 MPa, it generates a robust 6136 N of push force and 5734 N of pull force.
Because the lock physically holds the rod at the terminal position, the variable air cushion at the locker end is intentionally shorter (24 mm) compared to the free end cushion (40 mm). The cylinder uses a 1/2 PT port, a 32 mm carbon steel rod, and supports speeds of 30-500 mm/s. You can unlock the rod automatically by supplying release air to the designated port or by utilizing the manual release lever.
Airtac SAILB Rear Lock Cylinder SAILB125X25 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X25 |
|---|---|
| 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 (back 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 retracted (rod-in) 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 back-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 SAILB Rear Lock Cylinder SAILB125X25 Is Used
Vertical Load Holding
Maintains elevated platforms securely at the retracted stroke end during a sudden power or air loss, preventing uncommanded descent.
Clamp-and-Hold Station
Secures heavy workpieces at the end of the retraction cycle without consuming continuous compressed air, saving energy.
Safety Gate Lock
Keeps heavy safety gates firmly closed in the retracted position until the automatic air-release signal is actively supplied.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X25 the Right Lock Cylinder?
Select this 125 mm bore model when an application demands heavy load holding at the fully retracted position upon air loss or power failure. If your mechanism only requires 3927 N of push force at 0.5 MPa, stepping down to a 100 mm bore saves space; conversely, choose a 160 mm bore if you need the 10053 N thrust class. Crucially, the SAIL lock is a static holding device that engages only after the cylinder stops at the stroke end—it will not brake a moving rod, nor will it clamp at an arbitrary mid-stroke point (for that, use an AirTAC BSAI clamp-lock cylinder).
When matching a replacement, verify the 125 mm bore, 25 mm stroke, back locker position, 1/2 PT port threads, and your required mounting accessories (Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, or TCM2). Since the lock relies on a spring mechanism, avoid using fast-exhaust valves; back-pressure on the locker side can inadvertently release the lock, so an independent-exhaust solenoid valve is required. For any safety-critical lifting application, always add an independent mechanical safety measure.
Quick checklist
- ✓ Hold needed at the retracted (rod-in) end?
- ✓ Or lock anywhere → use BSAI
- ✓ Independent-exhaust valve fitted
- ✓ Port/thread type (PT/G)
- ✓ Extra safety measure for people
Airtac SAILB Rear Lock Cylinder SAILB125X25 FAQ
At a 0.5 MPa operating pressure, the 125 mm bore provides 6136 N of push force and 5734 N of pull force. At 0.7 MPa, the push force increases to 8590 N.
The lock is spring-applied and air-released, located in the back cover. It engages statically only when the rod reaches the retracted stroke end. It does not brake a moving rod or hold mid-stroke. Unlocking is done automatically via air release or manually via a lever.
Related AirTAC Lock & Standard Cylinders
Request a Quote for Airtac SAILB Rear Lock Cylinder SAILB125X25
Send us the quantity and destination. We confirm price, stock and lead time — usually within 7-8 hours.