Airtac SAILB Rear Lock Cylinder SAILB125X200
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X200 is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 200mm 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
- Stroke200 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X200
The AirTAC SAILB125X200 is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock housed 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. In the 125mm bore class, this actuator generates a push force of 6136N and a pull force of 5734N at 0.5MPa, making it well-suited for heavy vertical lifting tasks.
Unlike a standard SAI cylinder, this unit provides true static load-holding upon power loss. To manage deceleration, it features variable air cushions at both ends, though the locker-end cushion is notably shorter at 24mm compared to the 40mm free-end cushion. The lock disengages automatically via air supply or manually via a release lever, but you must avoid fast-exhaust valves; back-pressure on the locker side can unintentionally lift the lock, so an independent-exhaust solenoid valve is required.
Airtac SAILB Rear Lock Cylinder SAILB125X200 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X200 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 200 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 SAILB125X200 Is Used
Vertical Lift Power-Off Hold
Secures heavy elevated platforms in the retracted position instantly when air pressure drops, preventing uncontrolled descent.
Heavy Clamp End-Stop
Maintains high-force clamping pressure at the retracted stroke end without continuously consuming compressed air.
Gate Safety Locking
Keeps heavy industrial safety gates firmly closed and locked at the end of stroke until an intentional air release signal is sent.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X200 the Right Lock Cylinder?
Choose this 125mm bore model when an application demands substantial thrust, stepping up from the 80mm bore which provides 2513N push at 0.5MPa. Select the SAILB configuration specifically when the machinery must hold a load safely in the retracted position during a power failure. If your process requires the rod to be clamped at an arbitrary mid-stroke point rather than at the stroke terminal, the BSAI clamp-lock cylinder is the correct alternative. For any safety-critical lifting scenario where human safety depends on the load staying up, always add an independent mechanical safety measure alongside this pneumatic lock.
When ordering a replacement, verify the 125mm bore, 200mm stroke, back locker position, 1/2 PT port thread, and the standard carbon steel rod. This cylinder accepts the full AirTAC mounting set including Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, and TCM2 brackets. Since sensors are not built-in, add a magnet (-S) if you need to integrate CMSE reed or DMSE electronic solid-state switches into the dual-side sensor grooves.
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 SAILB125X200 FAQ
At an operating pressure of 0.5MPa, this 125mm bore cylinder provides a push (extension) force of 6136N and a pull (retraction) force of 5734N. The maximum operating pressure is 1.0MPa.
The SAILB125X200 features a spring-applied, air-released lock in the back cover that engages only when the piston reaches the retracted stroke end. It provides a static hold after the cylinder stops, not a dynamic brake, and can be unlocked automatically via air supply or manually via a lever.
Related AirTAC Lock & Standard Cylinders
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