Airtac SAILB Rear Lock Cylinder SAILB40X900
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X900 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 SAILB40X900
The AirTAC SAILB40X900 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock housed in the back cover. This lock safely holds the rod at the retracted stroke end without requiring live air pressure. In the 40mm bore class, it delivers 628N of push force and 528N of pull force at 0.5 MPa, making it well-suited for compact load-holding tasks.
Because the stroke is 900mm, this is a non-standard configuration exceeding the 800mm standard maximum. At this length, external guide rails are strongly recommended to prevent excessive side-loading on the carbon steel rod. The locker-end air cushion is shorter (20mm versus 27mm at the free end) to accommodate the locking mechanism, and the unit uses PT tapered ports.
Airtac SAILB Rear Lock Cylinder SAILB40X900 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X900 |
|---|---|
| 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 SAILB40X900 Is Used
Vertical Lift Hold
Secures vertical lifts in the retracted position during a power loss, preventing gravity-driven drops.
Conveyor Diverter
Holds a diverter arm safely retracted at the stroke end when the pneumatic system is depressurized.
Safety Gate Lock
Keeps a machine safety gate locked shut in the retracted position until the release air is supplied.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X900 the Right Lock Cylinder?
Choose this specific model when a compact pneumatic cylinder must secure a load safely in the retracted position upon power loss. If your application requires a higher holding capacity, stepping up to a 50mm bore provides 982N of push force at 0.5 MPa. Select SAILB for back-cover retracted holding; if the load must be held extended, choose a SAILF front-cover variant instead.
The lock engages only at the stroke terminal, meaning it cannot clamp the rod at an arbitrary mid-stroke position; for intermediate locking, a BSAI clamp-lock cylinder is required. Crucially, avoid using fast-exhaust valves with this cylinder, as back-pressure on the locker side can inadvertently release the spring lock; utilize an independent-exhaust solenoid valve instead. Always add an independent mechanical safety measure if human safety depends on the suspended load.
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 SAILB40X900 FAQ
At 0.5 MPa, the 40mm bore 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. It provides a static hold, not a dynamic brake, and is released automatically via air pressure or manually via a lever.
Related AirTAC Lock & Standard Cylinders
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