The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X250 is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 250mm 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.
The AirTAC SAILB50X250 is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. This spring-applied, air-released lock engages automatically when the piston reaches the retracted stroke end, securing the load without requiring live air pressure. You can release it pneumatically or via the manual override lever. Delivering 982N of push force at 0.5 MPa, it provides reliable holding power for vertical or suspended loads.
Unlike a plain SAI cylinder, this model safely holds the rod at the retracted terminal. The variable air cushion at the locker end is 20mm, which is shorter than the 30mm cushion on the free end, ensuring compact deceleration near the locked position. The standard carbon steel rod handles dynamic loads, and the extruded aluminum barrel is dimensionally interchangeable per ISO 15552 mounting interfaces.
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X250 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 250 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.
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.
| 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.
Secures raised loads at the top retracted stroke end instantly upon pneumatic pressure loss, preventing sudden drops in lifting jigs.
Locks the rod in the retracted position during an emergency stop or power loss to hold a diverter arm safely out of the product flow.
Holds a heavy pallet-gate mechanism firmly at the retracted stroke terminal while operators load inventory, ensuring the gate cannot drift.
Choose this 50mm bore when an application requires 982N push force at 0.5 MPa, stepping up from the 40mm bore (628N) for heavier vertical lifts, or down from the 63mm bore (1559N) when space is constrained. Select SAILB to hold the rod in the retracted position; choose SAILF if your load must remain extended. If you need to lock the rod at an arbitrary mid-stroke point rather than a stroke end, use the BSAI clamp-lock cylinder instead. Because the stroke is 250mm, use a guide rail to prevent excessive side-load wear on the rod seals. The lock is a static holding device that engages after the cylinder stops, not a dynamic brake. Avoid fast-exhaust valves, as back-pressure on the locker side can unintentionally release the lock; use an independent-exhaust solenoid valve. For human-safety critical suspended loads, add an independent mechanical safety measure. Replacement parts must match the 50mm bore, 250mm stroke, PT 1/4 port, and your required mounting.
Quick checklist
The 50mm bore provides 982N of push force and 825N of pull force at 0.5 MPa. At 0.7 MPa, the push force increases to 1374N.
The lock is spring-applied and air-released, engaging only at the retracted stroke end to provide a static hold. It unlocks automatically via air supply or manually via a lever. It does not clamp at mid-stroke; use BSAI for any-position locking.
Send us the quantity and destination. We confirm price, stock and lead time — usually within 7-8 hours.