Airtac SAILB Rear Lock Cylinder SAILB50X125
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X125 is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 125mm 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.
- BoreØ50 mm
- Stroke125 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X125
The AirTAC SAILB50X125 is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. It delivers 982N of push force and 825N of pull force at 0.5 MPa. The spring-applied, air-released lock engages automatically when the piston reaches the retracted stroke end, ensuring the load is held securely without requiring live air pressure. You can release the lock pneumatically or use the manual override lever.
This model features a 20mm carbon steel rod with an M16x1.5 thread and a 1/4 PT port. A notable design trait is the variable air cushion: the locker end uses a shorter 20mm cushion compared to the 30mm cushion on the free end. For position sensing, adding a magnet (-S) allows the use of AirTAC CMSE reed or DMSE solid-state sensors in the dual-side barrel grooves.
Airtac SAILB Rear Lock Cylinder SAILB50X125 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X125 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 125 mm |
| Acting type | Double acting, with lock |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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 – 800 mm/s |
| Cushion | Adjustable (30 mm free end / 20 mm lock end) |
| Max stroke | Up to 1200 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 (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 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 SAILB50X125 Is Used
Vertical Lift Hold
Maintains a lowered platform securely at the retracted stroke end during a power loss, preventing unintended descent.
Conveyor Arrest
Holds a stopped actuator firmly in place at the rod-in position to prevent product drift during processing.
Safety Gate Lock
Keeps a protective barrier closed and locked at the retracted end until the release air is actively supplied.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X125 the Right Lock Cylinder?
Choose this SAILB variant when your application requires the load to be held at the rod-in position. If you need higher force, stepping up to the 63mm bore yields 1559N push at 0.5 MPa; dropping to the 40mm bore provides 628N. If your machine requires locking at an arbitrary mid-stroke point rather than the stroke end, select the BSAI clamp-lock cylinder instead.
Remember that this lock is a static holding device, not a dynamic brake for a moving rod. Valve selection is critical: do not use a fast-exhaust valve, as back-pressure on the locker side can unintentionally release the lock. Always use an independent-exhaust solenoid valve, and add an independent safety measure if human safety depends on the load staying up. Replacement matches must mirror the 50mm bore, 125mm stroke, back locker position, PT port, and mounting style.
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 SAILB50X125 FAQ
At 0.5 MPa operating pressure, this 50mm bore cylinder provides 982N of push force and 825N of pull force. The maximum operating pressure is 1.0 MPa.
The lock is spring-applied and air-released, engaging only when the piston reaches the retracted stroke end in the back cover. It statically holds the load without live pressure; you unlock it by supplying release air or using the manual lever.
Related AirTAC Lock & Standard Cylinders
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