Airtac SAILB Rear Lock Cylinder SAILB40X300S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X300S is a genuine double-acting ISO 15552 profile cylinder with a Ø40mm 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.
- BoreØ40 mm
- Stroke300 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM12×1.25
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB40X300S
The AirTAC SAILB40X300-S is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock housed in the back cover. This safety mechanism engages automatically to hold the rod securely at the retracted stroke end whenever release air is cut, delivering reliable power-loss protection. It delivers 628N of push force at 0.5 MPa and includes a magnetic piston for position sensing.
Because the lock engages statically after the piston stops, it is not a mid-stroke clamp or a dynamic brake. The variable air cushion at the locker end is physically shorter (20mm versus 27mm at the free end) to accommodate the locking hardware. The extruded aluminum barrel includes sensor grooves for CMSE reed and DMSE electronic switches, while the carbon steel rod handles standard operational loads.
Airtac SAILB Rear Lock Cylinder SAILB40X300S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X300S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø40 mm |
| Stroke | 300 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 SAILB40X300S Is Used
Vertical Lift Safety
Holds a retracted vertical load securely in place during a sudden air pressure loss, preventing uncontrolled drops on lifting platforms.
End-of-Stroke Clamping
Maintains positive mechanical positioning at the retracted terminal end for precise component holding during machining or assembly.
Gate and Guard Hold
Keeps safety gates and machine guards firmly closed in the retracted state without consuming continuous live air pressure.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X300S the Right Lock Cylinder?
Choose this 40mm bore when an application requires 628N of push force at 0.5 MPa; step up to a 63mm bore if you need substantially more thrust (1559N at 0.5 MPa). Select this SAILB configuration specifically when the load must be held at the retracted position. If your application requires clamping at an arbitrary mid-stroke point, the BSAI clamp-lock cylinder is the correct choice instead.
For exact replacement matching, verify the 300mm stroke, back locker position, PT tapered port threads, and the -S magnet option. The 300mm stroke necessitates external guide rails to prevent excessive side-loading on the carbon steel rod. To maintain lock integrity, never use a fast-exhaust valve; always install an independent-exhaust solenoid valve, as back-pressure on the locker side can unintentionally release the lock. Safety-critical suspended loads still require independent mechanical stops.
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 SAILB40X300S FAQ
At 0.5 MPa operating pressure, this 40mm bore cylinder provides 628N of push force and 528N of pull force. At 0.7 MPa, the push force increases to 879N.
The lock is spring-applied and air-released, engaging only when the piston reaches the retracted stroke end in the back cover. It provides a static hold after the rod stops, not a dynamic brake. You can unlock it automatically by supplying release air or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
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