Airtac SAILB Rear Lock Cylinder SAILB50X300S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X300S is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 300mm 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
- Stroke300 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X300S
The AirTAC SAILB50X300-S is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock housed in the back cover. This mechanism engages automatically to hold the rod securely at the retracted stroke end whenever the release air is cut, dropping the load safely without relying on live pressure. Equipped with a sensor magnet, it supports position detection via AirTAC CMSE reed and DMSE electronic switches.
Delivering 982 N of push force and 825 N of pull force at 0.5 MPa, this 50 mm bore unit utilizes a 1/4 PT port and a 20 mm carbon steel rod. A key design detail is that the variable air cushion at the locker end is shortened to 20 mm compared to the 30 mm cushion on the free end. The lock is a static holding device, not a dynamic brake, meaning it secures the rod only after the cylinder has come to a complete stop.
Airtac SAILB Rear Lock Cylinder SAILB50X300S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X300S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 300 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 SAILB50X300S Is Used
Vertical Lift Safety
Holds a lifted load securely in the retracted position during a sudden air pressure loss, preventing uncontrolled drops on vertical lifting jigs.
Conveyor Snubber
Locks a diverter or gate in the retracted terminal position without consuming continuous air volume, maintaining a stable rest state during pauses.
Clamp and Hold
Secures a workpiece at the end of the retraction stroke, maintaining positive holding force on a fixture even if the main air supply is shut off.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X300S the Right Lock Cylinder?
Choose this 50 mm bore when an application requires 982 N push at 0.5 MPa, stepping up from a 40 mm bore (628 N) for heavier vertical loads, or down from a 63 mm bore (1559 N) to save space. Select the SAILB configuration when the load must be held in the retracted position; if the extended position needs holding, the SAILF variant is required. For applications needing clamping at an arbitrary mid-stroke point rather than the stroke end, the BSAI clamp-lock cylinder is the correct choice.
Because this model features a 300 mm stroke, external guide rails should be used to prevent excessive side-loading on the rod. Ensure the lock performs reliably by avoiding fast-exhaust valves; use an independent-exhaust solenoid valve instead, as back-pressure on the locker side can inadvertently release the lock. Always add an independent mechanical safety measure if human safety depends on the load remaining elevated. Replacement specifications must match the 50 mm bore, 300 mm stroke, back locker position, PT port threads, and the -S magnet option.
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 SAILB50X300S FAQ
At 0.5 MPa operating pressure, this 50 mm bore cylinder provides 982 N of push force and 825 N of pull force. At 0.7 MPa, the push force increases to 1374 N.
The lock is spring-applied and air-released, engaging only at the retracted stroke end to provide a static hold after the rod stops. It unlocks automatically by supplying air to the release port or via a manual release lever. It is not a mid-stroke clamp; for arbitrary position locking, use a BSAI cylinder.
Related AirTAC Lock & Standard Cylinders
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