Airtac SAILB Rear Lock Cylinder SAILB125X450S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X450S is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 450mm 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
- Stroke450 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X450S
The AirTAC SAILB125X450-S is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock housed in the back cover. Because it is a SAILB variant, the spring-applied, air-released lock engages precisely when the piston reaches the retracted stroke end, securely holding the rod and load in place without requiring continuous live air pressure. With a robust 125mm bore, it generates a substantial 5734N pull force at 0.5MPa, making it well-suited for heavy-duty vertical lifting and rigid positioning tasks.
This model includes a magnetic piston (-S) for use with CMSE reed and DMSE electronic sensors, and utilizes standard carbon steel rod material. To accommodate the locking hardware, the variable air cushion at the locker end is 24mm, which is intentionally shorter than the 40mm cushion found at the free end. The lock releases automatically via air supply to the release port or manually via a lever, providing reliable fail-safe load holding during power loss.
Airtac SAILB Rear Lock Cylinder SAILB125X450S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X450S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 450 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 SAILB125X450S Is Used
Vertical Lift Safety
Holds heavy elevated loads securely at the retracted stroke end during power loss, preventing sudden drops on lifting platforms.
Press Clamping
Maintains high-force clamping pressure at the stroke terminal without consuming continuous compressed air.
Gate Positioning
Locks heavy industrial gates or machinery guards in the closed position securely until an air signal releases the pin.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X450S the Right Lock Cylinder?
Choose this 125mm bore when substantial force is required; stepping down to a 100mm bore reduces the pull force to 3681N at 0.5MPa, while stepping up to a 160mm bore increases it to 9425N. Select the SAILB configuration when your application requires the load to be safely held at the rod-in position, whereas the SAILF variant holds at the extended rod-out position. If your application demands clamping at an arbitrary mid-stroke point rather than a stroke-end terminal, the BSAI clamp-lock cylinder is the correct alternative.
The lock is a static holding device that engages only after the cylinder has stopped, not a dynamic brake for a moving rod. It is critical to avoid using fast-exhaust valves with this cylinder; instead, use an independent-exhaust solenoid valve, as back-pressure on the locker side can unintentionally release the lock. For any safety-critical load suspension, always add an independent mechanical safety measure. At a 450mm stroke, use appropriate guide rails to prevent excessive side-loading on the rod. Replacement requires matching the 125mm bore, 450mm 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 SAILB125X450S FAQ
At a 0.5MPa operating pressure, this 125mm bore cylinder provides 6136N of push force and 5734N of pull force. At the maximum 1.0MPa pressure, it delivers up to 1251kgf.
The SAILB125X450-S features a spring-applied, air-released lock in the back cover that engages statically at the retracted stroke end. It unlocks automatically when air is supplied to the release port or manually via the release lever; it does not clamp at mid-stroke.
Related AirTAC Lock & Standard Cylinders
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