Airtac SAILB Rear Lock Cylinder SAILB40X800
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB40X800 is a genuine double-acting ISO 15552 profile cylinder with a Ø40mm bore, 800mm 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.
- BoreØ40 mm
- Stroke800 mm
- Port sizeG1/4
- Lock positionBack cover
- Rod threadM12×1.25
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB40X800
The AirTAC SAILB40X800 is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. Because it is a SAILB variant, the spring-applied, air-released lock engages only when the piston reaches the fully retracted stroke end, holding the carbon steel rod safely in place without requiring live air pressure. At 0.7 MPa it provides 879N of push force, making it well-suited for compact power-failure safety applications.
This model features a 1/4 PT tapered port and a variable air cushion on both ends, though the locker-end cushion is notably shorter at 20 mm compared to the 27 mm cushion on the free end. To ensure proper lock engagement, avoid using fast-exhaust valves; an independent-exhaust solenoid valve is required to prevent back-pressure from accidentally releasing the lock.
Airtac SAILB Rear Lock Cylinder SAILB40X800 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB40X800 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø40 mm |
| Stroke | 800 mm |
| Acting type | Double acting, with lock |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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 (27 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 (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 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 SAILB40X800 Is Used
Vertical Power-Failure Hold
Secures a lifted vertical load in the fully retracted position automatically when air pressure drops, preventing sudden crashes.
Retracted Safety Interlock
Keeps a guard door or clamp pulled back and safely locked at the stroke end during machine downtime.
End-of-Stroke Stop Block
Holds a conveyor diverter firmly in the home position without consuming continuous air, unlocking only when release air is supplied.
Is the Airtac SAILB Rear Lock Cylinder SAILB40X800 the Right Lock Cylinder?
Choose this 40 mm bore when you need static load-holding at the retracted position and a moderate thrust around 879N at 0.7 MPa. If your application requires less force, stepping down is not an option since SAIL has no 32 mm bore, so you must look outside the series; if you need significantly more holding power, step up to the 50 mm bore which offers 1374N at 0.7 MPa. Select SAILB specifically when the load must be secured in the rod-in position, whereas SAILF secures the extended rod-out position.
If the mechanism requires locking at an arbitrary mid-stroke point rather than the stroke end, bypass this model entirely and choose the BSAI clamp-lock cylinder instead. Remember that this lock is a static hold that engages after the cylinder stops, not a dynamic brake for a moving rod. For any human-safety-critical load, add an independent safety measure. Because this unit has an 800 mm stroke, integrating a linear guide is strongly recommended to prevent excessive side-load wear on the rod seals.
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 SAILB40X800 FAQ
The 40 mm bore provides 628N of push force at 0.5 MPa and 879N at 0.7 MPa. The pull force is 528N at 0.5 MPa, with a maximum operating pressure of 1.0 MPa.
The lock is spring-applied and air-released, engaging statically only when the rod reaches the fully retracted stroke end. It unlocks automatically via air supply or manually via a lever, but it cannot clamp at a mid-stroke position.
Related AirTAC Lock & Standard Cylinders
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