Airtac SAILB Rear Lock Cylinder SAILB40X900S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X900S is a genuine double-acting ISO 15552 profile cylinder with a Ø40mm bore, 900mm 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
- Stroke900 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM12×1.25
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB40X900S
The AirTAC SAILB40X900-S is a double-acting ISO 15552 profile cylinder featuring 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. It delivers a 0.7 MPa thrust of 879N and includes a magnet for precise position detection using CMSE reed or DMSE electronic sensors.
Unlike a plain SAI cylinder, this unit provides true power-failure safety, though the lock engages only after the piston stops at the stroke terminal, functioning as a static hold rather than a dynamic brake. The variable air cushion at the locker end is notably shorter at 20 mm compared to the 27 mm cushion on the free end. For pneumatic routing, the PT ported design requires careful valve selection to prevent back-pressure from unintentionally releasing the lock.
Airtac SAILB Rear Lock Cylinder SAILB40X900S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X900S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø40 mm |
| Stroke | 900 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 SAILB40X900S Is Used
Vertical Lift Hold
Maintains a raised load in the retracted position during sudden air pressure loss, preventing sudden drops on vertical lifting jigs.
Conveyor Snub
Locks a pneumatic stopper pin in the retracted terminal state to hold workpieces securely on a packaging conveyor line.
Safety Gate Lock
Keeps a machine safety gate retracted and locked open without consuming compressed air during operator load cycles.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X900S the Right Lock Cylinder?
Choose this specific SAILB configuration when a machine must safely hold a retracted vertical load during a power loss, stepping down from a 50 mm bore if the 1374N push force at 0.7 MPa is unnecessary, or stepping up if 879N is insufficient. If your application requires clamping at an arbitrary mid-stroke position rather than a stroke-end hold, select the BSAI clamp-lock cylinder instead. Because this is a 900 mm non-standard stroke exceeding the 800 mm standard maximum for a 40 mm bore, adding an external guide is highly recommended to manage side loads and prevent rod binding over the extended length.
When specifying a replacement, verify the 40 mm bore, 900 mm stroke, back locker position, PT tapered ports, and the -S magnet option. Always pair this cylinder with an independent-exhaust solenoid valve and avoid fast-exhaust valves, as locker-side back-pressure can lift the lock. For any safety-critical lifting application, always add an independent mechanical safety measure alongside the lock.
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 SAILB40X900S FAQ
At a 0.7 MPa operating pressure, this 40 mm bore cylinder provides a push force of 879N and a pull force of 528N. The maximum operating pressure is 1.0 MPa.
The lock is spring-applied and air-released, engaging only when the piston reaches the retracted stroke end in the back cover. Supplying air to the release port unlocks it automatically, or a manual lever can override it. It provides a static hold, not a dynamic brake.
Related AirTAC Lock & Standard Cylinders
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