Airtac SAILB Rear Lock Cylinder SAILB40X50
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X50 is a genuine double-acting ISO 15552 profile cylinder with a Ø40mm bore, 50mm 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.
- BoreØ40 mm
- Stroke50 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM12×1.25
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB40X50
The AirTAC SAILB40X50 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock housed in the back cover. This built-in brake engages automatically when the piston reaches the retracted stroke end, securely holding a load of up to 628N at 0.5MPa without requiring continuous live air pressure. It provides a true power-failure safety hold that a standard SAI cylinder cannot offer.
Unlike a dynamic brake, this static lock engages only after the rod has fully stopped at the terminal position. The variable air cushion at the locker end measures 20mm, which is intentionally shorter than the 27mm cushion on the free end. For position detection, you can add a magnet (-S) to use AirTAC CMSE reed or DMSE solid-state sensors.
Airtac SAILB Rear Lock Cylinder SAILB40X50 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X50 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø40 mm |
| Stroke | 50 mm |
| Acting type | Double acting, with lock |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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 (27 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 (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 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 SAILB40X50 Is Used
Vertical Load Holding
Maintains up to 628N of load in the retracted position during a power loss, preventing sudden drops on lifting rigs.
End-of-Stroke Clamp
Secures a workpiece or tool firmly at the retracted stroke end without consuming continuous compressed air.
Safety Gate Hold
Keeps safety barriers and heavy gates locked closed until an intentional air release signal is applied.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X50 the Right Lock Cylinder?
Choose this 40mm bore when your application requires 628N of push force at 0.5MPa and a fail-safe retracted-end hold. If you need more power, stepping up to the 50mm bore yields 982N of push force; if less force is needed, remember SAIL does not come in a 32mm size. Select SAILB to lock the rod in the retracted position and SAILF to hold the extended position. If your process requires clamping at an arbitrary mid-stroke point, choose the BSAI clamp-lock cylinder instead.
This lock is a static holding device, not a mid-stroke clamp or moving-rod brake. Avoid using fast-exhaust valves with this cylinder; back-pressure on the locker side can unintentionally release the lock, so use an independent-exhaust solenoid valve. For human-safety critical loads, always add an independent mechanical safety measure. Replacement matches require 40mm bore, 50mm stroke, back locker position, PT ports, and your chosen mounting (Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, TCM2).
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 SAILB40X50 FAQ
At 0.5MPa, the 40mm bore provides 628N of push force and 528N of pull force. At 0.7MPa, the push force increases to 879N.
The spring-applied, air-released lock engages automatically when the piston reaches the retracted stroke end in the back cover. It is a static hold, not a mid-stroke clamp. You can unlock it by supplying air to the release port (automatic) or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
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