Airtac SAILB Rear Lock Cylinder SAILB50X250S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X250S is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 250mm 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
- Stroke250 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X250S
The AirTAC SAILB50X250-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, cutting the release air drives a lock pin into the carbon steel rod, securely holding the load at the retracted stroke end without requiring live pressure. In this 50mm bore class, it delivers a 0.5 MPa push force of 982N and a pull force of 825N.
The integrated lock engages only after the piston reaches the stroke terminal on the locker side, functioning as a static holding device rather than a dynamic brake. For position feedback, the included -S magnet works seamlessly with AirTAC CMSE reed and DMSE electronic sensors. Note that the variable air cushion at the locker end is 20mm, intentionally shorter than the 30mm cushion at the free end to accommodate the locking hardware.
Airtac SAILB Rear Lock Cylinder SAILB50X250S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X250S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 250 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 SAILB50X250S Is Used
Vertical Lift Power Failure Safety
Prevents a 982N elevated load from dropping unexpectedly by engaging the back-cover lock at the retracted stroke end the moment air pressure is lost.
Retracted Position Holding
Maintains a secure mechanical hold on the tooling in the rod-in position without consuming compressed air during extended idle periods.
Access Guard Restraint
Locks a safety barrier or guard firmly in the open position until a controlled air signal releases the mechanism for operator access.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X250S the Right Lock Cylinder?
Choose this 50mm bore SAIL model when an application requires a 982N push force at 0.5 MPa; stepping down to a 40mm bore reduces the push force to 628N, while moving up to a 63mm bore increases it to 1559N. Select the SAILB configuration when the load must be held safely in the retracted position, and choose a SAILF variant instead if the extended position requires holding. If your process requires clamping at an arbitrary mid-stroke point rather than the stroke end, select the BSAI clamp-lock cylinder instead.
Remember that the lock provides a static hold only after the cylinder stops; it will not arrest a moving rod. Valve selection is critical: never use a fast-exhaust valve with this cylinder, as back-pressure on the locker side can unintentionally release the lock—always use an independent-exhaust solenoid valve. For safety-critical suspended loads, add an independent mechanical safety measure. To replace this unit, match the 50mm bore, 250mm stroke, back locker position, PT tapered port threads, and the -S magnet. Given the 250mm stroke, ensure external guide rails are used to prevent excessive side-load wear on the rod.
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 SAILB50X250S FAQ
At an operating pressure of 0.5 MPa, the 50mm bore provides a push force of 982N and a pull force of 825N. 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 after the piston stops. It provides a static hold, not a dynamic brake. Unlocking is achieved automatically by supplying release air or manually via the release lever.
Related AirTAC Lock & Standard Cylinders
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