Airtac SAILB Rear Lock Cylinder SAILB125X225
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X225 is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 225mm 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
- Stroke225 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X225
The AirTAC SAILB125X225 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock built into the back cover. Because the lock resides in the rear, it secures the rod automatically at the fully retracted stroke end. This 125mm bore generates 6136N of push and 5734N of pull at 0.5 MPa, making it suited for heavy load control. The 225mm stroke is a non-standard configuration, so verify overall length requirements before installation.
The lock engages statically after the piston stops at the retracted terminal; it is not a dynamic brake for a moving rod, nor does it clamp at arbitrary mid-stroke points. For mid-stroke clamping, the BSAI series is required instead. The variable air cushion at the locker end is 24mm, intentionally shorter than the 40mm cushion on the free end. A carbon steel rod and PT tapered ports are standard, and the extruded aluminum barrel features dual sensor grooves for mounting position switches.
Airtac SAILB Rear Lock Cylinder SAILB125X225 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X225 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 225 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 SAILB125X225 Is Used
Vertical Load Holding
Secures heavy lifted masses in the retracted position automatically when air pressure drops, preventing gravity-driven falls.
Power Failure Safety
Maintains a safely retracted state during sudden power outages, keeping heavy gates or machinery guarded without live pressure.
Heavy Clamp Securement
Holds a 125mm bore clamping arm firmly retracted at the stroke end while workpieces are transferred or unloaded.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X225 the Right Lock Cylinder?
Select this 125mm bore when an application demands high load holding at the retracted position without relying on live air pressure. If you need less force, the 100mm bore offers 3681N of pull at 0.5 MPa; if you need more, the 160mm bore provides 9425N of pull. Choose SAILB specifically when the load must be secured in the rod-in position, whereas SAILF secures the extended rod-out position.
When implementing this cylinder, avoid using a fast-exhaust valve, as back-pressure on the locker side can unintentionally release the lock; an independent-exhaust solenoid valve is required. If human safety depends on the load remaining retracted, add an independent mechanical safety measure. To replace this unit, match the 125mm bore, 225mm non-standard stroke, back locker position, PT port threads, and the desired mounting style from the ISO 15552 set (Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, TCM2).
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 SAILB125X225 FAQ
At 0.5 MPa, the push force is 6136N and the pull force is 5734N. At 0.7 MPa, the push force is 8590N, and at 0.9 MPa, it reaches 11045N.
The lock is spring-applied and air-released. It holds the rod statically at the retracted stroke end only, not mid-stroke. Unlocking is achieved automatically by supplying release air to the port or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
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