Airtac SAILB Rear Lock Cylinder SAILB50X300
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB50X300 is a genuine double-acting ISO 15552 profile cylinder with a Ø50mm bore, 300mm 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
- Stroke300 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB50X300
The AirTAC SAILB50X300 is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. Because the lock is spring-applied and air-released, cutting the release air drives a lock pin into the carbon steel rod, securely holding the load at the retracted stroke end without consuming live pressure. In the 50mm bore class, it generates 982N of push force and 825N of pull force at 0.5 MPa, making it well-suited for moderate vertical holding tasks.
Unlike a plain SAI cylinder, this SAIL variant provides true power-failure safety, though it functions strictly as a static hold that engages after the piston stops, not as a dynamic brake. The variable air cushion at the locker end is notably shorter at 20mm compared to 30mm on the free end, ensuring the deceleration profile accommodates the lock mechanism. For position sensing, adding a magnet (-S) allows the use of AirTAC CMSE reed or DMSE solid-state sensors.
Airtac SAILB Rear Lock Cylinder SAILB50X300 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB50X300 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø50 mm |
| Stroke | 300 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 SAILB50X300 Is Used
Vertical Power-Failure Hold
Secures lifted loads in the retracted position instantly when air pressure drops, preventing sudden crashes.
Retracted Stroke Safety
Keeps gates or guards locked closed at the back stroke end without needing continuous air supply.
Clamp and Hold Station
Maintains a 982N clamping force at the retracted terminal for static machining or assembly processes.
Is the Airtac SAILB Rear Lock Cylinder SAILB50X300 the Right Lock Cylinder?
Select this 50mm bore model when an application requires 982N push force at 0.5 MPa, stepping up from a 40mm bore (628N) for heavier loads, or down from a 63mm bore (1559N) when space is constrained. Choose this SAILB configuration to hold the rod in the retracted position; if the extended position must be held instead, the SAILF variant is required. If the mechanism needs to lock at an arbitrary mid-stroke point rather than a stroke end, select the BSAI clamp-lock cylinder instead.
At 300mm stroke, lateral side-loads can damage the rod seals, so an external guide should be used to support the load. The lock holds statically at the stroke end, so avoid using a fast-exhaust valve; an independent-exhaust solenoid valve is mandatory because back-pressure on the locker side can accidentally release the lock. For human-safety critical overhead loads, always add an independent mechanical safety measure beyond the pneumatic lock. Replacement requires matching the 50mm bore, 300mm stroke, back locker position, PT port threads, and the desired mounting style from the full ISO 15552 set (Basic, FA, FB, CA, CB, CR, LB, TC, FTC, TCM1, 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 SAILB50X300 FAQ
At 0.5 MPa operating pressure, the 50mm bore provides 982N of push force and 825N of pull force. At the maximum 1.0 MPa, it delivers up to 200 kgf.
The lock is spring-applied and air-released, engaging only at the retracted stroke end after the rod stops. It unlocks automatically via air supply or manually via a lever, but it cannot clamp at mid-stroke.
Related AirTAC Lock & Standard Cylinders
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