Airtac SAILB Rear Lock Cylinder SAILB50X80
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X80 is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 80mm 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
- Stroke80 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X80
The AirTAC SAILB50X80 is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. It delivers 982N of push force and 825N of pull force at 0.5 MPa. The lock is spring-applied and air-released, meaning it safely holds the rod at the retracted stroke end without requiring continuous live air pressure. You can unlock it automatically by supplying release air or by using the manual release lever.
Unlike a standard SAI cylinder, this unit is designed specifically for power-loss safety. The variable air cushion at the locker end is 20mm, which is shorter than the 30mm cushion on the free end. This cylinder uses a carbon steel rod and PT threaded ports. It does not include a magnet for sensors, but if position detection is needed, an -S variant works with AirTAC CMSE reed and DMSE electronic solid-state switches.
Airtac SAILB Rear Lock Cylinder SAILB50X80 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X80 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 80 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 SAILB50X80 Is Used
Vertical Lift Holding
Prevents a 50mm bore vertical lift from dropping under gravity when air pressure is removed, holding the load securely at the retracted stroke end.
Power-Out Safety Clamp
Maintains a clamped position securely at the stroke end during a sudden power loss, ensuring the workpiece remains held without live pressure.
Gate Position Retention
Keeps heavy safety gates or machine doors locked in the closed retracted position until release air is actively supplied to the unlock port.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X80 the Right Lock Cylinder?
Choose this 50mm bore when you need 982N of push force at 0.5 MPa, stepping up from the 40mm bore which provides 628N. If your application requires holding the load at the extended stroke end instead of the retracted position, select the SAILF50X80. If you need to clamp the rod at an arbitrary mid-stroke point rather than a stroke end, the BSAI clamp-lock cylinder is the correct choice.
Remember that the SAIL lock is a static holding device that engages after the cylinder stops, not a dynamic brake for a moving rod. Do not use a fast-exhaust valve with this lock cylinder; always use an independent-exhaust solenoid valve because back-pressure on the locker side can unintentionally release the lock. If human safety depends on the load staying up, add an independent safety measure. Replacement requires matching the 50mm bore, 80mm stroke, back locker position, PT port thread, and mounting style.
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 SAILB50X80 FAQ
At 0.5 MPa, the push force is 982N and the pull force is 825N. At 0.7 MPa, the push force increases to 1374N. The maximum operating pressure is 1.0 MPa.
The lock is spring-applied and air-released, engaging only at the retracted stroke end to provide a static hold. It is not a dynamic brake and cannot hold at mid-stroke. Unlocking is done automatically by supplying release air or manually via the release lever.
Related AirTAC Lock & Standard Cylinders
Request a Quote for Airtac SAILB Rear Lock Cylinder SAILB50X80
Send us the quantity and destination. We confirm price, stock and lead time — usually within 7-8 hours.