Airtac BSAI Locking Clamp Cylinder BSAI125X50
The AirTAC Airtac BSAI Locking Clamp Cylinder BSAI125X50 is a genuine double-acting ISO 15552 cylinder with a Ø125mm bore, 50mm stroke and a spring-applied, air-released clamp-lock that holds the rod at ANY position along its travel — with a static holding force of 8600 N.
- BoreØ125 mm
- Stroke50 mm
- Cylinder portG1/2
- TypeSingle rod (BSAI)
- Enclasp portG1/8
- Rod threadM27×2
About the Airtac BSAI Locking Clamp Cylinder BSAI125X50
The AirTAC BSAI125X50 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released clamp-lock mechanism. A defining trait of this series is its capacity to lock the rod at any position along its 50 mm travel, delivering a robust static holding force of 8600 N. The cylinder generates 6136 N of push thrust at 0.5 MPa, but the 8600 N holding force is a separate quantity entirely; you must size the clamp against the static load weight, not the cylinder thrust.
This bidirectional enclasp grips the rod whether it was extending or retracting, engaging only after the piston has come to a complete stop, meaning it cannot brake a moving load. Unlocking requires a separate G1/8 air port and balanced pressures on both piston sides to prevent the rod from jumping abruptly upon release. The integrated variable air cushions merely decelerate the piston near stroke ends, while the clamp itself does the actual holding.
Airtac BSAI Locking Clamp Cylinder BSAI125X50 Technical Specifications
| Model | Airtac BSAI Locking Clamp Cylinder BSAI125X50 |
|---|---|
| Series | BSAI ISO 15552 clamp-lock cylinder |
| Bore size | Ø125 mm |
| Stroke | 50 mm |
| Type | Single rod (BSAI), double acting |
| Cylinder port | G1/2 |
| Rod thread | M27×2 |
| Lock type | Spring-applied, air-released clamp (any position) |
|---|---|
| Static holding force | 8600 N |
| Enclasp / unlock port | G1/8 |
| Operating pressure | 0.15 – 0.7 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Max stroke | Up to 1000 mm |
Specifications follow the official AirTAC BSAI datasheet (ISO 15552). Operating pressure is 0.15–0.7 MPa (lower than a plain SAI). Port options: PT / G.
How the Clamp-Lock Holds
static holding force (Ø125 mm)
A spring-applied gripper clamps the rod and holds the load at any position in the stroke — not just at the stroke end (that is a SAIL) — and it is bidirectional: it holds whether the rod was extending or retracting.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa (max) | 8590 N | — |
Push/pull as tabulated. Rated to the 0.7 MPa operating maximum for this series. The clamp holding force (8600 N) is separate from cylinder thrust. Size with a margin.
Where the Airtac BSAI Locking Clamp Cylinder BSAI125X50 Is Used
Vertical Load Holding
Secures heavy elevated platens at any point in the 50 mm stroke, preventing gravity-driven drops when air pressure is removed.
Power Loss Safety
Engages instantly upon air loss to freeze a mid-stroke workpiece in place, protecting operators and tooling from sudden falls.
Machining Position Hold
Clamps the rod rigidly during secondary operations or inspection, ensuring the part does not shift despite cutting forces.
Is the Airtac BSAI Locking Clamp Cylinder BSAI125X50 the Right Clamp-Lock?
Choose this 125 mm bore when a heavy vertical load demands an 8600 N static hold anywhere in the travel, whereas a smaller neighbour like the BSAI80X50 offers 3600 N holding force and 2513 N thrust at 0.5 MPa. If you only need to hold the load at the stroke end, a plain SAIL end-lock cylinder suffices, but BSAI is required for mid-stroke clamping. For simple extension and retraction without any holding requirement, a standard SAI cylinder is the better fit.
When replacing this unit, match the single-rod configuration, 125 mm bore, 50 mm stroke, and PT-threaded 1/2 inch cylinder ports. It accepts Basic, FA, FB, CA, CB, CR, LB, TC, TCM1, and TCM2 mounts. The sturdy M27x2 rod thread handles high side loads, and since no magnet is specified, position sensing via CMSE or DMSE switches is not enabled out of the box. Remember that safety-critical loads need an independent mechanical measure, as this clamp cannot arrest dynamic motion.
Quick checklist
- ✓ Hold needed at any position?
- ✓ Or stroke-end only → use SAIL
- ✓ Holding force ≥ your load
- ✓ Balanced-pressure unlock circuit
- ✓ Extra safety measure for people
Airtac BSAI Locking Clamp Cylinder BSAI125X50 FAQ
The clamp-lock provides a static holding force of 8600 N and can secure the rod at any position along the 50 mm stroke, not just at the ends.
The spring-applied clamp engages only after the cylinder stops, so it cannot brake a moving rod. To unlock safely, you must apply air to the G1/8 enclasp port with balanced pressures on both sides of the piston, preventing abrupt rod movement.
Related AirTAC Lock & Standard Cylinders
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