Airtac SAILB Rear Lock Cylinder SAILB125X75S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X75S is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 75mm 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
- Stroke75 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X75S
The AirTAC SAILB125X75-S is a double-acting ISO 15552 profile cylinder featuring a built-in spring-applied, air-released mechanical lock in the back cover. Because the lock engages when the piston reaches the retracted stroke end, it securely holds the load in place without requiring continuous live air pressure. In this 125mm bore size, the cylinder delivers a robust 6136N push force at 0.5 MPa, making it well-suited for heavy vertical load management.
This model includes a magnetic piston (-S) for use with AirTAC CMSE reed and DMSE electronic sensors, allowing precise end-of-stroke detection. A notable design detail is that the variable air cushion at the locker end is shorter (24mm) than at the free end (40mm). Remember that the lock is a static holding device and not a dynamic brake, meaning it engages only after the cylinder has come to a complete stop.
Airtac SAILB Rear Lock Cylinder SAILB125X75S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X75S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 75 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 SAILB125X75S Is Used
Vertical Load Safety
Holds heavy lifted loads securely at the retracted stroke end on the back cover side, preventing crashes during sudden air pressure loss.
Clamp and Hold
Maintains strong clamping force at the end of the stroke without consuming continuous air, ensuring stable positioning during machining.
Gate and Lift Locking
Provides a reliable mechanical lock for safety gates and lifting platforms, keeping equipment safely parked when inactive.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X75S the Right Lock Cylinder?
Choose this 125mm bore when a 100mm bore (providing 3927N push at 0.5 MPa) is insufficient for your load, or step down if a 100mm unit offers enough force. Select this SAILB configuration specifically when you need the load held securely at the retracted rod-in position; choose a SAILF variant instead if the extended rod-out position must be held. If your application requires locking at an arbitrary mid-stroke point rather than at the stroke end, the BSAI clamp-lock cylinder is the correct alternative.
When integrating this cylinder, strictly avoid using a fast-exhaust valve, as back-pressure on the locker side can unintentionally release the lock; always use an independent-exhaust solenoid valve. For any application where human safety depends on the load remaining elevated, always add an independent safety measure alongside the lock. Replacement requires matching the 125mm bore, 75mm stroke, PT tapered port thread, carbon steel rod, back locker position, 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 SAILB125X75S FAQ
At an operating pressure of 0.5 MPa, this 125mm bore cylinder provides a push force of 6136N and a pull force of 5734N. At 0.7 MPa, the push force increases to 8590N.
The lock is spring-applied and air-released, engaging automatically when the rod reaches the retracted stroke end in the back cover. It is a static hold that engages after stopping, not a mid-stroke clamp or dynamic brake. Unlocking is achieved by supplying air to the release port or by using the manual release lever.
Related AirTAC Lock & Standard Cylinders
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