Airtac SAILB Rear Lock Cylinder SAILB125X150
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X150 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 SAILB125X150
The AirTAC SAILB125X150 is a double-acting ISO 15552 profile cylinder featuring 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 securely holds the rod-in position without requiring live air pressure. This bore size delivers a robust 6136N push force at 0.5 MPa, making it well suited for heavy lifting tasks.
The lock releases automatically via an air signal or by using the manual release lever. For precise end-of-stroke deceleration, the variable air cushion at the locker end is notably shorter at 24mm compared to the 40mm cushion on the free end. The carbon steel rod provides high tensile strength, and position sensing is available by specifying the -S magnet option to pair with CMSE reed or DMSE electronic switches.
Airtac SAILB Rear Lock Cylinder SAILB125X150 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X150 |
|---|---|
| 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 SAILB125X150 Is Used
Vertical Lift Safety
Holds heavy lifted loads securely in the retracted position instantly if air pressure drops, preventing sudden falls on vertical actuators.
Power-Off Clamping
Maintains solid clamping force against a workpiece at the rod-in stroke end during facility power loss or emergency stop events.
Gate and Guard Holding
Secures heavy safety gates or machine guards in the closed position mechanically, requiring an active air signal to unlock.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X150 the Right Lock Cylinder?
Select this 125mm bore model when a 100mm bore (providing 3927N push at 0.5 MPa) lacks the thrust for your load, but you want to avoid stepping up to a 160mm bore. Choose the SAILB configuration specifically when the load must be secured in the retracted position; select a SAILF variant instead if the extended rod-out end requires holding. If your application demands clamping at an arbitrary mid-stroke point rather than a stroke-end static hold, the BSAI clamp-lock cylinder is the correct choice.
Remember that this lock is a static holding device that engages after the cylinder stops, not a dynamic brake for a moving rod. Avoid using fast-exhaust valves, as back-pressure on the locker side can unintentionally release the lock; always use an independent-exhaust solenoid valve. For safety-critical loads that could endanger personnel if they drop, add an independent mechanical safety measure. Replacement specifications: 125mm bore, 150mm stroke, back locker, PT tapered ports, and standard mounting options including Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, and TCM2.
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 SAILB125X150 FAQ
At 0.5 MPa operating pressure, the 125mm bore provides 6136N of push force and 5734N of pull force. At 0.7 MPa, the push force increases to 8590N.
The spring-applied lock engages automatically when the rod reaches the retracted stroke end in the back cover, holding the load without live air. It releases via an air signal or manual lever, but it only holds at this specific end position, not mid-stroke.
Related AirTAC Lock & Standard Cylinders
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