Airtac SAILB Rear Lock Cylinder SAILB40X400
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X400 is a genuine double-acting ISO 15552 profile cylinder with a Ø40mm bore, 400mm 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
- Stroke400 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM12×1.25
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB40X400
The AirTAC SAILB40X400 is a double-acting profile cylinder dimensionally interchangeable per ISO 15552, featuring a built-in mechanical lock in the back cover. A spring-applied, air-released lock pin engages when the piston reaches the retracted stroke end, securely holding the load without requiring live air pressure. With a 16mm carbon steel rod and a 0.7 MPa thrust of 879N, it provides reliable power-failure safety for vertical or suspended loads.
Unlike a standard SAI cylinder, this SAIL variant incorporates a static holding lock rather than a dynamic brake. The variable air cushion at the locker end is 20mm, deliberately shorter than the 27mm cushion at the free end to accommodate the locking mechanism. For automated monitoring, you can add a magnet for CMSE reed or DMSE electronic sensors.
Airtac SAILB Rear Lock Cylinder SAILB40X400 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X400 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø40 mm |
| Stroke | 400 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 SAILB40X400 Is Used
Vertical Lift Safety
Holds a lifted platen securely at the retracted top position during a power loss, preventing sudden drops.
Pallet Stopper
Locks a stopper block in the rod-in position to hold a pallet on a line while pressure is removed.
Safety Gate Hold
Maintains a safety gate in the closed retracted position without consuming continuous air supply.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X400 the Right Lock Cylinder?
Choose this 40mm bore cylinder when an application requires holding a load at the retracted rod-in position; for holding at the extended position, select the SAILF40X400 instead. If your process demands locking at an arbitrary mid-stroke point rather than the stroke end, the BSAI clamp-lock cylinder is the required alternative. For higher force needs, stepping up to the 50mm bore increases 0.5 MPa thrust from 628N to 982N.
Because this is a 400mm stroke, fitting external guide rails is recommended to prevent side-load damage to the rod. The lock engages statically after the cylinder stops, so never use a fast-exhaust valve; an independent-exhaust solenoid valve is mandatory because back-pressure on the locker side can unintentionally release the lock. If human safety depends on the load remaining up, add an independent safety measure. Replacement matches: 40mm bore, 400mm stroke, back locker, PT ports, standard mounting, no magnet.
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 SAILB40X400 FAQ
At 0.7 MPa operating pressure, the 40mm bore provides 879N of push force and 528N of pull force. It operates at speeds between 30 and 800 mm/s.
The spring-applied, air-released lock engages statically when the rod reaches the retracted stroke end in the back cover. It does not clamp at mid-stroke. Unlocking is done automatically by supplying air to the release port or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
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