Airtac SAILB Rear Lock Cylinder SAILB125X150S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X150S is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 150mm 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
- Stroke150 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X150S
The AirTAC SAILB125X150-S is a double-acting ISO 15552 profile cylinder equipped with a 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 relying on live pressure. In the 125mm bore class, it generates 6136N of push force and 5734N of pull force at 0.5 MPa, making it well-suited for heavy vertical lifting tasks.
This model includes a magnetic piston for position sensing with CMSE reed and DMSE electronic solid-state switches. A notable design trait is the shorter variable air cushion at the locker end (24mm) compared to the free end (40mm), which accommodates the locking hardware. The lock is a static holding device that engages after the piston stops, not a dynamic brake for a moving rod.
Airtac SAILB Rear Lock Cylinder SAILB125X150S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X150S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 150 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 SAILB125X150S Is Used
Vertical Lift Safety
Holds heavy elevated loads securely at the retracted stroke end during a power loss, preventing sudden drops in vertical lifting mechanisms.
End-of-Stroke Clamping
Maintains a rigid, pressure-free hold on the retracted rod for machining or clamping stations that require zero pneumatic energy to sustain force.
Gate and Door Hold
Secures heavy industrial gates or warehouse doors in the closed position mechanically, ensuring they remain shut until air is supplied to release.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X150S the Right Lock Cylinder?
Choose this 125mm bore when a 100mm bore (providing 3927N push at 0.5 MPa) is insufficient for your load, but a 160mm bore (10053N) would be excessive. Select the SAILB configuration specifically when the load must be secured in the retracted position; if you need to hold the extended position, the SAILF variant is required instead. If your application requires locking at an arbitrary mid-stroke point rather than a stroke end, the BSAI clamp-lock cylinder is the correct choice.
For safe operation, avoid using fast-exhaust valves, as back-pressure on the locker side can unintentionally release the lock; an independent-exhaust solenoid valve is required. The PT port thread is standard. For any safety-critical application where human safety depends on the load staying up, always add an independent safety measure. At a 150mm stroke, side loads are minimal, but ensure proper mounting alignment using the full range of ISO 15552 mounting options like TC or LB.
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 SAILB125X150S FAQ
At 0.5 MPa operating pressure, the 125mm bore provides 6136N of push force and 5734N of pull force. At the maximum 1.0 MPa, it delivers a push force of 1251 kgf.
The lock is spring-applied and air-released, meaning it engages automatically when the piston reaches the retracted stroke end in the back cover. It provides a static hold after the rod stops, not a dynamic brake. To unlock, you supply air to the release port or use the manual release lever.
Related AirTAC Lock & Standard Cylinders
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