Airtac SAILB Rear Lock Cylinder SAILB50X400S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X400S 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 SAILB50X400S
The AirTAC SAILB50X400-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 engages a lock pin into the carbon steel rod when the piston reaches the retracted stroke end. This mechanism holds the load securely without requiring continuous live air pressure, delivering a thrust of 982N at 0.5MPa. The integrated -S magnet enables precise position tracking using CMSE reed or DMSE solid-state sensors.
A critical design detail is that the variable air cushion at the locker end is shorter (20mm) compared to the free end cushion (30mm). Remember that this lock is a static holding device for the stroke-end position only; it is not a dynamic brake for a moving rod, nor can it clamp at an arbitrary mid-stroke point.
Airtac SAILB Rear Lock Cylinder SAILB50X400S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X400S |
|---|---|
| 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 SAILB50X400S Is Used
Vertical Lift Safety
Secures elevated loads in the retracted position instantly if air pressure drops, preventing sudden crashes in lifting rigs.
Conveyor Hold
Locks a shuttle or diverter firmly at the retracted stroke end during workpiece transfer pauses to halt unintended motion.
Power Failure Guard
Maintains a guarded gate in the closed position during power outages, requiring an air signal to unlock and move.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X400S the Right Lock Cylinder?
Choose this 50mm bore model when an application requires 982N of push force at 0.5MPa. If your project needs less force, the 40mm bore offers 628N; if more power is required, stepping up to the 63mm bore provides 1559N. Select this SAILB configuration to hold loads safely in the retracted position upon power loss. If your mechanism requires locking at an arbitrary mid-stroke point rather than the stroke end, the BSAI clamp-lock cylinder is the correct choice instead.
For reliable operation, avoid using fast-exhaust valves, as back-pressure on the locker side can unintentionally release the lock; an independent-exhaust solenoid valve is required. With a 400mm stroke, this cylinder is susceptible to side-load deflection, so rigid guide rails or load-bearing carriages are strongly recommended. For safety-critical lifting applications that could cause injury if the load drops, always add an independent mechanical safety measure alongside the lock. Replacement parts must match the 50mm bore, 400mm stroke, PT port threads, back locker position, and -S magnet specification.
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 SAILB50X400S FAQ
At 0.5MPa operating pressure, this 50mm bore cylinder provides 982N of push force and 825N of pull force. At the maximum 1.0MPa pressure, it delivers up to 200kgf.
The lock is spring-applied and air-released, engaging automatically when the piston reaches the retracted stroke end to hold the load without live pressure. It unlocks via an air signal to the release port or a manual lever, but it only holds at this specific stroke end, not mid-stroke.
Related AirTAC Lock & Standard Cylinders
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