Airtac SAILB Rear Lock Cylinder SAILB50X225
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X225 is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm 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.
- BoreØ50 mm
- Stroke225 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X225
The AirTAC SAILB50X225 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock built into the back cover. This integrated lock engages when the piston reaches the retracted stroke end, securely holding the rod in place without requiring continuous live air pressure. With a 50mm bore, it generates 982N of push force and 825N of pull force at 0.5 MPa, making it well-suited for medium-duty vertical load management.
Unlike a plain SAI actuator, this SAIL model provides true static load-holding upon power loss. The variable air cushion at the locker end is notably shorter, measuring 20mm compared to the 30mm cushion on the free end. It operates at speeds of 30-800 mm/s, and the carbon steel rod uses an M16x1.5 thread. For position detection, adding a magnet (-S) allows the use of CMSE reed or DMSE electronic sensors.
Airtac SAILB Rear Lock Cylinder SAILB50X225 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X225 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 225 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 SAILB50X225 Is Used
Vertical Lift Hold
Prevents gravity-driven drops on lifting platforms by mechanically locking the retracted rod position the moment air pressure is cut.
Clamp and Hold
Maintains secure clamping force on machined parts at the retracted stroke end without continuously consuming compressed air.
Power Failure Safety
Acts as a fail-safe mechanism for safety gates and heavy doors, holding the load securely in the retracted state during sudden outages.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X225 the Right Lock Cylinder?
Select this 50mm bore actuator when your application requires a reliable hold at the retracted position and 982N of thrust at 0.5 MPa is sufficient. If your mechanism demands greater power, stepping up to the 63mm bore yields 1559N of push force at the same pressure. Conversely, lighter loads can utilize the 40mm bore offering 628N. Because the lock is situated in the back cover, it specifically secures the rod-in state; if your process requires holding at the extended rod-out position, the SAILF variant is required instead.
For applications needing to freeze the rod at an arbitrary mid-stroke point rather than a stroke end, AirTAC's BSAI clamp-lock cylinder is the correct alternative. Crucially, the SAIL lock is a static holding device that engages only after the cylinder stops, not a dynamic brake for a moving rod. Avoid using fast-exhaust valves, as back-pressure on the locker side can unintentionally release the lock; an independent-exhaust solenoid valve is required. At 225mm of stroke, ensure external guide rails are used to prevent excessive side-loading on the rod. Replacement parts must match the 50mm bore, 225mm stroke, back locker position, PT port threads, and standard mounting options.
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 SAILB50X225 FAQ
The 50mm bore generates 982N of push force and 825N of pull force at 0.5 MPa, scaling up to 1767N of push force at 0.7 MPa. It operates at a speed range of 30-800 mm/s.
The lock is spring-applied and air-released, located in the back cover to hold the rod only at the fully retracted stroke end. It engages statically after the cylinder stops and can be unlocked automatically via air supply or manually via a lever.
Related AirTAC Lock & Standard Cylinders
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