Airtac BSAI Locking Clamp Cylinder BSAI125X250
The AirTAC Airtac BSAI Locking Clamp Cylinder BSAI125X250 is a genuine double-acting ISO 15552 cylinder with a Ø125mm bore, 250mm 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
- Stroke250 mm
- Cylinder portG1/2
- TypeSingle rod (BSAI)
- Enclasp portG1/8
- Rod threadM27×2
About the Airtac BSAI Locking Clamp Cylinder BSAI125X250
The AirTAC BSAI125X250 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released clamp-lock mechanism. It provides a robust static holding force of 8600 N, gripping the 32 mm carbon steel piston rod securely at any position along its 250 mm stroke. The cylinder delivers a practical push thrust of 8590 N at 0.7 MPa, but the 8600 N clamp holding force is a distinct mechanical specification separate from pneumatic thrust—buyers must size the holding capacity against the static load weight, not the cylinder's motive thrust.
This enclasp unit requires a third G1/8 pneumatic port to release the brake, operating within a balanced pressure range of 0.15-0.7 MPa. Unlike the variable air cushions at the stroke ends which only decelerate the piston near travel limits, the clamp mechanism is what actually secures the load. For position feedback, the extruded aluminum barrel features sensor grooves compatible with AirTAC CMSE reed and DMSE electronic switches, though this specific configuration is supplied without a magnet.
Airtac BSAI Locking Clamp Cylinder BSAI125X250 Technical Specifications
| Model | Airtac BSAI Locking Clamp Cylinder BSAI125X250 |
|---|---|
| Series | BSAI ISO 15552 clamp-lock cylinder |
| Bore size | Ø125 mm |
| Stroke | 250 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 BSAI125X250 Is Used
Vertical Z-Axis Holding
Prevents heavy platens from dropping on air loss by clamping the rod at any intermediate height along the vertical travel.
Machining Position Lock
Freezes the workpiece carriage at a precise intermediate point for drilling or inspection without relying on continuous pneumatic pressure.
Emergency Drop Safety
Acts as a fail-safe gripper that engages instantly when the cylinder stops, securing the load independently of the air supply.
Is the Airtac BSAI Locking Clamp Cylinder BSAI125X250 the Right Clamp-Lock?
Step down to the 100 mm bore if your payload is lighter; it yields 3927 N push thrust at 0.5 MPa and a 5500 N holding force, which may better suit standard handling. Choose this BSAI125X250 over a SAIL model when you need the rod gripped mid-stroke rather than only at the end caps. If the application just requires moving a load without intermediate holding, a plain SAI cylinder is sufficient. This model features PT tapered ports and accepts Basic, FA, FB, CA, CB, CR, LB, TC, TCM1, and TCM2 mounts.
Remember that the clamp locks only after the rod has completely stopped; it cannot brake a moving load. Unlocking requires balanced air pressure on both sides of the piston, or the rod may jump abruptly. For safety-critical human-adjacent operations, an additional independent mechanical safety measure is mandatory. The robust M27x2 rod thread handles high side-loading, but for any stroke exceeding 300 mm, always use an external guide rail to prevent rod binding.
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 BSAI125X250 FAQ
The built-in enclasp clamp provides a static holding force of 8600 N. It is bidirectional, meaning it grips the rod securely whether the cylinder was extending or retracting, and it can hold the load at any position along the 250 mm stroke.
No. The clamp locks only after the cylinder has stopped; it is not a dynamic brake. Additionally, it must be unlocked with balanced air pressures on both sides of the piston to prevent the rod from jumping abruptly upon release.
Related AirTAC Lock & Standard Cylinders
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