Airtac SAILB Rear Lock Cylinder SAILB40X25S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X25S is a genuine double-acting ISO 15552 profile cylinder with a Ø40mm 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.
- BoreØ40 mm
- Stroke25 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM12×1.25
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB40X25S
The AirTAC SAILB40X25-S is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. Because it is a SAILB variant, the spring-applied, air-released lock engages precisely at the retracted stroke end to hold the carbon steel rod safely in place. At 0.5 MPa, this 40mm bore generates 628N of push force and 528N of pull force, making it ideal for compact power-failure safety tasks.
This unit includes a piston magnet for CMSE reed and DMSE electronic sensors. A critical design detail is that the variable air cushion at the locker end is only 20mm, noticeably shorter than the 27mm cushion on the free end, ensuring the locking pin engages without delay. The lock itself provides a static hold after the cylinder stops; it is not a dynamic mid-stroke brake.
Airtac SAILB Rear Lock Cylinder SAILB40X25S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X25S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø40 mm |
| Stroke | 25 mm |
| Acting type | Double acting, with lock |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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 – 800 mm/s |
| Cushion | Adjustable (27 mm free end / 20 mm lock end) |
| Max stroke | Up to 1200 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 (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 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 SAILB40X25S Is Used
Vertical Retract Hold
Secures a lifted platen in the retracted position during a power loss, preventing gravity-driven crashes.
End-of-Stroke Clamp
Holds a workpiece firmly at the retracted stroke end without consuming continuous compressed air.
Gate Safety Hold
Keeps a safety gate locked shut at the rod-in terminal until the release air is actively supplied.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X25S the Right Lock Cylinder?
Choose this 40mm bore when your application requires 628N of push force at 0.5 MPa; step down if your load is lighter, or up to a 50mm bore (982N push) for heavier demands. Select this SAILB configuration to hold the rod at the retracted end on power loss, whereas a SAILF holds the extended end. If you need to clamp and hold the load at an arbitrary mid-stroke position, select the BSAI clamp-lock cylinder instead.
For safe operation, never use a fast-exhaust valve with this cylinder; always use an independent-exhaust solenoid valve, as back-pressure on the locker side can unintentionally release the lock. If human safety depends on the load staying retracted, add an independent safety measure. Replacement matches require 40mm bore, 25mm stroke, back locker, PT tapered port, and the -S magnet.
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 SAILB40X25S FAQ
At 0.5 MPa, this 40mm bore cylinder provides 628N of push force and 528N of pull force. At 0.7 MPa, the push force increases to 879N.
The lock is spring-applied and air-released, engaging only at the retracted stroke end to provide a static hold. It unlocks automatically via air supply or manually via a lever, but it does not clamp at mid-stroke.
Related AirTAC Lock & Standard Cylinders
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