Airtac SAILB Rear Lock Cylinder SAILB40X400S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X400S 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 SAILB40X400S
The AirTAC SAILB40X400-S is a double-acting ISO 15552 profile cylinder equipped with a built-in mechanical lock in the back cover. Because the lock is spring-applied and air-released, cutting the release air drives a lock pin into the carbon steel rod, securely holding the load at the retracted stroke end without requiring live pressure. In the 40mm bore class, it generates 879N of push force at 0.7 MPa, making it highly effective for compact power-failure safety tasks.
This model includes a piston magnet for position sensing with CMSE reed or DMSE electronic switches. A critical mechanical detail is that the variable air cushion at the locker end is 20mm, deliberately shorter than the 27mm cushion on the front end, ensuring the locking mechanism fits properly without compromising end-of-stroke deceleration.
Airtac SAILB Rear Lock Cylinder SAILB40X400S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X400S |
|---|---|
| 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 SAILB40X400S Is Used
Vertical Lift Safety
Holds a retracted vertical load securely in place automatically during a sudden compressed air loss or power failure.
Clamp and Hold
Maintains constant clamping force at the rod-in stroke end without consuming continuous air pressure.
Gate Safety Locking
Prevents heavy safety gates from sliding open accidentally by mechanically locking the retracted piston.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X400S the Right Lock Cylinder?
Choose this 40mm bore lock cylinder when an application demands a reliable static hold at the retracted position during an air-pressure drop. If your project requires greater thrust, stepping up to the 50mm bore raises the 0.5 MPa push force from 628N to 982N. Select the SAILB configuration specifically when the rod-in state is the safe resting position; for holding a load at the extended rod-out end, the SAILF variant is required instead.
Because this unit features a 400mm stroke, using a side-load guide is strongly recommended to prevent rod bearing wear over extended travel distances. Remember that this lock engages statically only after the piston stops at the stroke terminal; it is not a dynamic brake for a moving rod, nor does it clamp at arbitrary mid-stroke points (which requires a BSAI clamp-lock cylinder). To maintain lock integrity, never use a fast-exhaust valve, as back-pressure on the locker side can unintentionally release the lock. For human-safety critical overhead loads, always add an independent mechanical safety measure. Replacement specifications require a 40mm bore, 400mm stroke, back locker position, PT port threads, and the -S magnet option.
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 SAILB40X400S FAQ
At 0.7 MPa operating pressure, the 40mm bore provides 879N of push force and 879N of pull force. At the maximum 1.0 MPa pressure, it delivers up to 128 kgf of push force.
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 cylinder stops, not a dynamic brake. You can unlock it automatically by supplying air to the release port or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
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