Airtac BSAI Locking Clamp Cylinder BSAI125X300S
The AirTAC Airtac BSAI Locking Clamp Cylinder BSAI125X300S is a genuine double-acting ISO 15552 cylinder with a Ø125mm bore, 300mm 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
- Stroke300 mm
- Cylinder portG1/2
- TypeSingle rod (BSAI)
- Enclasp portG1/8
- Rod threadM27×2
About the Airtac BSAI Locking Clamp Cylinder BSAI125X300S
The AirTAC BSAI125X300-S is a double-acting ISO 15552 profile cylinder equipped with a spring-applied, air-released clamp-lock. It delivers a robust 6136 N of thrust at 0.5 MPa and securely holds the piston rod at any position along its 300 mm travel with a static holding force of 8600 N. You must size the clamp's holding capacity against your static load, not the cylinder thrust, because these are two separate quantities. The integrated bidirectional gripper engages only after the rod has stopped, meaning it cannot brake a moving load.
This 125 mm bore model uses a 1/2 inch PT cylinder port and a separate G1/8 enclasp port to release the lock. The variable air cushion at the stroke ends only decelerates the piston and is not a holding device. Fitted with a magnet (-S), it supports AirTAC CMSE reed and DMSE solid-state sensors for position feedback. Because the stroke is 300 mm, the 32 mm rod and M27x2 thread provide substantial side-load resistance, though an external guide is recommended for heavy loads.
Airtac BSAI Locking Clamp Cylinder BSAI125X300S Technical Specifications
| Model | Airtac BSAI Locking Clamp Cylinder BSAI125X300S |
|---|---|
| Series | BSAI ISO 15552 clamp-lock cylinder |
| Bore size | Ø125 mm |
| Stroke | 300 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 BSAI125X300S Is Used
Vertical Load Holding
Prevents heavy vertical loads from dropping when air pressure is lost, clamping the rod securely at any height along the 300 mm stroke.
Machining Position Lock
Holds a workpiece rigidly at a specific intermediate travel point for machining or inspection, ensuring no deflection during the process.
Power Failure Safety
Acts as an emergency brake by engaging the spring-applied clamp instantly upon air loss, stopping the rod exactly where it stopped.
Is the Airtac BSAI Locking Clamp Cylinder BSAI125X300S the Right Clamp-Lock?
Select this 125 mm bore model when a load needs to be held mid-stroke with high force, stepping up from the 100 mm bore which offers 3927 N thrust at 0.5 MPa and a 5500 N holding force. Choose BSAI over SAIL when you need to lock at any position rather than just at the stroke end, or choose a plain SAI if no clamping is required. Remember that the clamp locks only after the cylinder stops and must be unlocked with balanced air pressures to prevent the rod from jumping abruptly; safety-critical applications require an independent external safety measure.
This model is a direct replacement for a single-rod, 125 mm bore, 300 mm stroke cylinder with PT port threads. It accepts Basic, FA, FB, CA, CB, CR, LB, TC, TCM1, and TCM2 mounts. The included -S magnet works with AirTAC CMSE and DMSE switches.
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 BSAI125X300S FAQ
The clamp-lock provides a static holding force of 8600 N. It engages a spring-applied gripper on the rod to hold the load at any position bidirectionally, but only after the cylinder has come to a complete stop.
The lock is released by applying 0.15-0.7 MPa of air pressure to the G1/8 enclasp port, but only after the air pressures on both sides of the piston are balanced. If pressures are not balanced, the rod can jump abruptly upon release.
Related AirTAC Lock & Standard Cylinders
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