Airtac BSAI Locking Clamp Cylinder BSAI40X125
The AirTAC Airtac BSAI Locking Clamp Cylinder BSAI40X125 is a genuine double-acting ISO 15552 cylinder with a Ø40mm bore, 125mm 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 900 N.
- BoreØ40 mm
- Stroke125 mm
- Cylinder portG1/4
- TypeSingle rod (BSAI)
- Enclasp portG1/8
- Rod threadM12×1.25
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac BSAI Locking Clamp Cylinder BSAI40X125
The AirTAC BSAI40X125 is a double-acting ISO 15552 profile cylinder featuring a built-in spring-applied, air-released clamp-lock. It provides a static holding force of 900 N at any position along its 125 mm stroke. This bidirectional enclasp grips the 16 mm carbon steel rod directly, ensuring the load stays put without relying on continuous air pressure. The cylinder generates 628 N of thrust at 0.5 MPa, but remember that holding force and thrust are separate quantities; you must size the 900 N clamp capacity against your static load, not the pneumatic thrust.
This unit features PT tapered port threads and a separate G1/8 enclasp port to manage the locking mechanism. The clamp locks only after the cylinder has stopped, meaning it cannot brake a moving rod. To unlock safely, the air pressures on both sides of the piston must be balanced, otherwise the rod can jump abruptly. Additionally, the variable air cushion only decelerates the piston near the stroke end; the clamp is the actual holding device.
Airtac BSAI Locking Clamp Cylinder BSAI40X125 Technical Specifications
| Model | Airtac BSAI Locking Clamp Cylinder BSAI40X125 |
|---|---|
| Series | BSAI ISO 15552 clamp-lock cylinder |
| Bore size | Ø40 mm |
| Stroke | 125 mm |
| Type | Single rod (BSAI), double acting |
| Cylinder port | G1/4 |
| Rod thread | M12×1.25 |
| Lock type | Spring-applied, air-released clamp (any position) |
|---|---|
| Static holding force | 900 N |
| Enclasp / unlock port | G1/8 |
| Operating pressure | 0.15 – 0.7 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 800 mm/s |
| Max stroke | Up to 800 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 (Ø40 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 (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa (max) | 880 N | — |
Push/pull as tabulated. Rated to the 0.7 MPa operating maximum for this series. The clamp holding force (900 N) is separate from cylinder thrust. Size with a margin.
Where the Airtac BSAI Locking Clamp Cylinder BSAI40X125 Is Used
Vertical Axis Hold
Secures a lifted load at any point in the vertical travel path, preventing falls when pneumatic pressure is removed.
Emergency Drop Prevention
Engages instantly upon air loss to freeze the rod in place, protecting tools and workpieces from sudden crashes.
Machining Position Hold
Locks the rod firmly mid-stroke to withstand cutting forces during drilling or milling operations.
Is the Airtac BSAI Locking Clamp Cylinder BSAI40X125 the Right Clamp-Lock?
Choose this 40 mm bore when a 32 mm bore lacks sufficient holding capacity (the 32 mm offers 402 N thrust and 600 N holding force) or when a 50 mm bore is excessive (offering 982 N thrust and 1400 N holding force). Select BSAI over a SAIL model when you need the load held at an arbitrary mid-stroke position rather than just at the stroke end. If the application only requires standard movement without position holding, a plain SAI cylinder is sufficient.
For replacements, match the single-rod configuration, 40 mm bore, 125 mm stroke, PT port threads, and the correct mounting set (Basic, FA, FB, CA, CB, CR, LB, TC, TCM1, TCM2). Because this model lacks the -S magnet, it cannot use CMSE or DMSE sensors. Always ensure the rod has stopped before applying the clamp, and add an independent safety measure for human-safety-critical loads. The 16 mm rod thread handles side loads well, though long unsupported strokes still need an external guide.
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 BSAI40X125 FAQ
The BSAI40X125 provides a static holding force of 900 N. This bidirectional clamp locks the rod at any position along the stroke to hold the load securely without continuous air pressure.
The clamp locks only after the cylinder has stopped and cannot brake a moving rod. To release it safely, the air pressures on both sides of the piston must be balanced; otherwise, the rod can move abruptly upon unlocking.
Related AirTAC Lock & Standard Cylinders
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