Airtac SAILB Rear Lock Cylinder SAILB50X400
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X400 is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 400mm 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
- Stroke400 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X400
The AirTAC SAILB50X400 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock housed in the back cover. It securely holds the rod at the retracted stroke end, delivering 982N of push force and 825N of pull force at 0.5 MPa. This power-loss safety mechanism engages automatically when release air is cut, ensuring your vertical loads remain safely in place without consuming live pressure.
A standout design trait is the shorter variable air cushion at the locker end (20mm) compared to the free end (30mm), which effectively decelerates the piston before the static lock engages. The carbon steel rod utilizes an M16x1.5 thread, and because this model lacks a magnet, position sensing requires external limit switches rather than internal CMSE or DMSE electronic or reed sensors.
Airtac SAILB Rear Lock Cylinder SAILB50X400 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X400 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 400 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 SAILB50X400 Is Used
Vertical Lift Safety
Holds retracted vertical loads securely in place during a compressed air failure or power loss event on lifting platforms.
Clamp and Hold
Maintains positive holding force on a workpiece at the retracted stroke end without requiring continuous live air pressure.
Gate Retention
Secures heavy pneumatic gates or diverters in the closed position, preventing drift caused by vibration or load shifts.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X400 the Right Lock Cylinder?
Select this 50mm bore when an application demands 982N push force at 0.5 MPa, stepping up from a 40mm bore (628N) if you need heavier load capacity, or down to a 63mm bore (1559N) if higher thrust is required. Choose the SAILB configuration specifically when the load must be secured in the retracted position; if your process requires holding at the extended end, select the SAILF variant instead. For applications needing mid-stroke clamping rather than end-of-stroke holding, the BSAI clamp-lock cylinder is the correct choice.
Because the lock is a static holding device that engages only after the cylinder stops, it will not brake a moving rod. Pneumatic routing is critical: avoid fast-exhaust valves, as back-pressure on the locker side can inadvertently release the lock—always use an independent-exhaust solenoid valve. At 400mm of stroke, the M16x1.5 carbon steel rod is susceptible to side-loading; utilize guided mounts to prevent rod bending and premature seal wear. If human safety depends on the load staying retracted, install an independent mechanical safety measure alongside the lock.
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 SAILB50X400 FAQ
At 0.5 MPa operating pressure, the SAILB50X400 provides 982N of push force and 825N of pull force. At 0.7 MPa, the push force increases to 1374N.
The lock is spring-applied and air-released, engaging only at the retracted stroke end (back cover) after the piston stops. It is a static hold, not a dynamic brake. To unlock, supply air to the release port for automatic release, or use the manual release lever.
Related AirTAC Lock & Standard Cylinders
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