Airtac SAILB Rear Lock Cylinder SAILB125X200S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X200S 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 SAILB125X200S
The AirTAC SAILB125X200-S is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock housed in the back cover. It securely holds the rod at the retracted stroke end, delivering a robust 6136N push force at 0.5 MPa. This model includes a magnet for position sensing and uses a standard carbon steel rod.
The lock engages automatically via spring force when air is cut, ensuring the load stays put without live pressure, and releases by supplying air to the release port or using the manual lever. Note that the variable air cushion at the locker end is 24mm, which is shorter than the 40mm cushion on the free end, a specific design trait to accommodate the locking hardware.
Airtac SAILB Rear Lock Cylinder SAILB125X200S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X200S |
|---|---|
| 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 SAILB125X200S Is Used
Vertical Lift Power-Off Hold
Maintains heavy vertical loads safely in the retracted position during a sudden air pressure loss or supply shutdown.
Safety Gate Locking
Secures heavy machine safety gates in the closed position without consuming continuous live air pressure.
Clamp and Hold at End
Provides a reliable static hold on large workpieces at the retracted stroke end for extended machining cycles.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X200S the Right Lock Cylinder?
Choose this 125mm bore when an 80mm bore (2513N push at 0.5 MPa) lacks the lifting force, but a 160mm bore (10053N) is physically excessive. Select a back-locker (SAILB) configuration to hold the load safely at the rod-in retracted position; choose a front-locker (SAILF) if you need to hold the extended rod-out position. If your application requires clamping at an arbitrary mid-stroke point rather than the stroke end, use the AirTAC BSAI clamp-lock cylinder instead.
This SAIL lock is a static holding device that engages after the cylinder stops, 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 inadvertently release the lock—always use an independent-exhaust solenoid valve. For safety-critical lifting applications where human safety depends on the load staying up, add an independent mechanical safety measure. Replacement matches require 125mm bore, 200mm stroke, PT tapered port threads, and the -S magnet for CMSE reed and DMSE electronic sensors.
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 SAILB125X200S FAQ
At 0.5 MPa operating pressure, this 125mm bore cylinder provides 6136N of push force and 5734N of pull force. At 0.7 MPa, the push force increases to 8590N.
The lock is spring-applied and air-released, located in the back cover to hold the rod only at the retracted stroke end. It engages statically after the piston stops and is released automatically by supplying air to the release port or manually via a lever.
Related AirTAC Lock & Standard Cylinders
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