Airtac SAILB Rear Lock Cylinder SAILB125X900
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X900 is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm 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.
- BoreØ125 mm
- Stroke900 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X900
The AirTAC SAILB125X900 is a double-acting ISO 15552 profile cylinder equipped with a spring-applied, air-released mechanical lock housed in the back cover. Because the lock engages when the piston reaches the retracted stroke end, it secures your load safely without requiring continuous live air pressure. In the 125 mm bore class, this actuator generates 6136 N of push thrust and 5734 N of pull thrust at 0.5 MPa, making it well suited for heavy vertical lifting tasks.
This model features a 32 mm carbon steel rod and a 1/2 inch PT port, operating at speeds between 30 and 500 mm/s. The variable air cushion at the locker end is specifically machined shorter at 24 mm compared to the free end at 40 mm to accommodate the locking mechanism. You can release the lock automatically by supplying air to the release port, or manually via the lever, and the extruded aluminum barrel includes sensor grooves for adding CMSE or DMSE position switches.
Airtac SAILB Rear Lock Cylinder SAILB125X900 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X900 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 900 mm |
| Acting type | Double acting, with lock |
| Port size | G1/2 |
| Rod thread | M27×2 |
| 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 – 500 mm/s |
| Cushion | Adjustable (40 mm free end / 24 mm lock end) |
| Max stroke | Up to 1500 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 (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 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 SAILB125X900 Is Used
Vertical Lift Safety
Holds heavy elevated loads securely in the retracted position during a sudden air pressure loss, preventing crashes on heavy lifting rigs.
Pallet Stopper
Locks a 900 mm extended stopper blade in place at the end of stroke to halt heavy pallets without consuming continuous pneumatic air.
Machine Guard Hold
Maintains a safety guard fully retracted during maintenance, ensuring the barrier stays open even if the main air supply is disconnected.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X900 the Right Lock Cylinder?
Select this 125 mm bore when a smaller 100 mm cylinder lacks sufficient force, as the 100 mm bore provides 3927 N of push at 0.5 MPa compared to the 6136 N offered here. Choose the SAILB configuration when the load must be held securely in the retracted position; if you need to secure the rod while extended, select the SAILF variant instead. Because this is a static holding lock that engages only at the stroke terminal, you must choose the BSAI clamp-lock cylinder if your application requires locking at an arbitrary mid-stroke position.
For reliable operation, avoid using fast-exhaust valves with this actuator, as back-pressure on the locker side can inadvertently release the lock; always use an independent-exhaust solenoid valve. If human safety depends on the load remaining elevated, implement an additional independent safety measure. With a 900 mm stroke, ensure adequate side-load guidance to prevent rod bending. Replacement parts must match the 125 mm bore, 900 mm stroke, back locker position, PT port thread, and mounting style (such as FA, FB, LB, or TC).
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 SAILB125X900 FAQ
At 0.5 MPa operating pressure, this 125 mm bore cylinder provides 6136 N of push force and 5734 N of pull force. At 0.7 MPa, the push force increases to 8590 N.
The spring-applied, air-released lock engages statically at the retracted stroke end to hold the load without live pressure. You can unlock it automatically by supplying air to the release port, or use the manual release lever.
Related AirTAC Lock & Standard Cylinders
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