Airtac SAILB Rear Lock Cylinder SAILB50X900
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X900 is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 900mm 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
- Stroke900 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X900
The AirTAC SAILB50X900 is a double-acting, single-rod ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. Because this is a SAILB configuration, the spring-applied, air-released lock engages when the piston reaches the retracted stroke end, securely holding the load without requiring continuous air pressure. With a 50mm bore, it delivers 982N of push force and 825N of pull force at 0.5MPa, making it well-suited for medium-duty vertical holding tasks.
This model features a carbon steel rod and PT tapered port threads. The variable air cushion at the locker end is 20mm, which is intentionally shorter than the 30mm cushion at the free end to accommodate the locking mechanism. The lock releases automatically via air supply or manually via a lever, but avoid using fast-exhaust valves, as back-pressure on the locker side can inadvertently release the lock.
Airtac SAILB Rear Lock Cylinder SAILB50X900 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X900 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 900 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 SAILB50X900 Is Used
Vertical Lift Hold
Secures elevated platforms or vertical loads in the retracted position automatically upon air pressure loss, preventing accidental descent.
End-of-Stroke Clamp
Maintains a firm mechanical hold on a workpiece at the retracted stroke end without consuming continuous compressed air.
Safety Gate Hold
Keeps heavy safety gates or guards locked closed during power outages until the release air is restored.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X900 the Right Lock Cylinder?
Choose this 50mm bore when a 40mm bore (628N push at 0.5MPa) lacks the force to lift your load, or step up to a 63mm bore (1559N push at 0.5MPa) if your mass requirements grow. Select the SAILB variant when the load must be held in the retracted position; choose SAILF if the extended position needs holding. If your application requires clamping at an arbitrary mid-stroke point rather than a stroke-end hold, use the BSAI clamp-lock cylinder instead. This 900mm stroke exceeds the 50mm bore's 1200mm maximum standard stroke limit, classifying it as a non-standard stroke; for a stroke of this length, always use an external guide to prevent rod side-loading and premature seal wear.
When specifying a replacement, verify the 50mm bore, 900mm stroke, back locker position, 1/4 inch PT port, and your required mounting style (Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, or TCM2). This unit has no magnet; if position sensing is needed, select an -S variant and pair it with AirTAC CMSE reed or DMSE solid-state sensors. Remember that the lock is a static holding device that engages after the cylinder stops, not a dynamic brake for a moving rod. If human safety depends on the load staying up, add an independent safety measure.
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 SAILB50X900 FAQ
At 0.5MPa, the 50mm bore provides 982N of push force and 825N of pull force. At 0.7MPa, the push force increases to 1374N. The maximum operating pressure is 1.0MPa.
The lock is spring-applied and air-released, located in the back cover. It engages statically only when the piston reaches the retracted stroke end, holding the load without live pressure. It does not clamp at mid-stroke or stop a moving rod. Unlocking is done automatically by supplying air to the release port or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
Request a Quote for Airtac SAILB Rear Lock Cylinder SAILB50X900
Send us the quantity and destination. We confirm price, stock and lead time — usually within 7-8 hours.