Airtac SAILB Rear Lock Cylinder SAILB50X25S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X25S is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm 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.
- BoreØ50 mm
- Stroke25 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X25S
The AirTAC SAILB50X25-S is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. Because the lock is spring-applied and air-released, it automatically secures the piston rod at the retracted stroke-end whenever the release air is cut, holding a 982N load at 0.5MPa without relying on live pressure. It includes a standard magnet for CMSE reed and DMSE electronic sensors.
This model uses a 1/4 PT port and a 20mm carbon steel rod. The variable air cushion at the locker end is 20mm, intentionally shorter than the 30mm cushion on the free end to accommodate the locking mechanism. The lock is a static holding device, not a dynamic brake, and engages only after the cylinder comes to a complete stop at the stroke terminal.
Airtac SAILB Rear Lock Cylinder SAILB50X25S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X25S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 25 mm |
| Acting type | Double acting, with lock |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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 (30 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 (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 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 SAILB50X25S Is Used
Vertical Retract Hold
Secures elevated loads in the retracted position during a power loss, preventing gravity-driven falls.
Clamp and Secure
Maintains clamping force on a workpiece at the stroke end without continuously consuming compressed air.
Safety Gate Hold
Keeps safety gates and guards locked in the closed position until the release air is actively supplied.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X25S the Right Lock Cylinder?
Choose this 50mm bore to step up from the 40mm version (628N push at 0.5MPa) when your application requires the 982N thrust class. Select the SAILB configuration when the load must be held in the retracted position; if you need to secure the rod in the extended position, the SAILF variant is required. If your process demands locking at an arbitrary mid-stroke point rather than the stroke end, use the BSAI clamp-lock cylinder instead.
For safe operation, never use a fast-exhaust valve with this lock cylinder; an independent-exhaust solenoid valve is mandatory because back-pressure on the locker side can unintentionally release the lock. If human safety depends on the load remaining retracted, add an independent mechanical safety measure. Replacement requires matching the 25mm stroke, back locker position, PT port threads, 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 SAILB50X25S FAQ
At a 0.5 MPa operating pressure, this 50mm bore cylinder provides a push force of 982N and a pull force of 825N. The maximum thrust is 200 kgf at 1.0 MPa.
The lock is spring-applied and air-released, meaning it engages automatically to hold the rod at the retracted stroke end when air is cut. It unlocks only when release air is supplied or the manual lever is used. It is a static hold, not a mid-stroke clamp or dynamic brake.
Related AirTAC Lock & Standard Cylinders
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