Airtac BSAI Locking Clamp Cylinder BSAI125X900S
The AirTAC Airtac BSAI Locking Clamp Cylinder BSAI125X900S is a genuine double-acting ISO 15552 cylinder with a Ø125mm bore, 900mm 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
- Stroke900 mm
- Cylinder portG1/2
- TypeSingle rod (BSAI)
- Enclasp portG1/8
- Rod threadM27×2
About the Airtac BSAI Locking Clamp Cylinder BSAI125X900S
The AirTAC BSAI125X900-S is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released clamp-lock mechanism. It secures the carbon steel piston rod at ANY position along its 900mm travel, delivering a robust static holding force of 8600 N. Because this is the single-rod variant, it generates 6136 N of push thrust and 5734 N of pull thrust at 0.5 MPa. It is crucial to distinguish holding force from thrust: the 8600 N clamp rating is the static load capacity of the brake, entirely separate from the pneumatic thrust that moves the load.
This 125mm bore model operates within a 0.15-0.7 MPa pressure range and includes a -S magnet for CMSE reed and DMSE solid-state sensors. The enclasp mechanism requires a third G1/8 pneumatic port to release the brake, ensuring the clamp stays engaged even if air pressure is lost. Remember that the variable air cushions only decelerate the piston near stroke ends; they do not hold the load. Furthermore, the clamp locks only after the rod stops and cannot brake a moving load.
Airtac BSAI Locking Clamp Cylinder BSAI125X900S Technical Specifications
| Model | Airtac BSAI Locking Clamp Cylinder BSAI125X900S |
|---|---|
| Series | BSAI ISO 15552 clamp-lock cylinder |
| Bore size | Ø125 mm |
| Stroke | 900 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 BSAI125X900S Is Used
Vertical Load Holding
Suspends heavy vertical platens securely at any point in the 900mm travel, relying on the 8600 N clamp rather than constant air pressure.
Power Loss Safety
Engages the spring-applied brake instantly if compressed air supply drops, freezing the rod in place to prevent gravity-driven crashes.
Machining Position Hold
Locks the extended rod rigidly during secondary milling or inspection processes, ensuring the workpiece remains entirely immobile.
Is the Airtac BSAI Locking Clamp Cylinder BSAI125X900S the Right Clamp-Lock?
Select this 125mm bore model when an application requires massive mid-stroke holding capacity, stepping up from the 100mm bore which offers 3927 N push at 0.5 MPa and a 5500 N hold. Choose BSAI over a SAIL cylinder when you need to secure a load anywhere in the 900mm travel, rather than just at stroke ends. If the machine only needs end-of-stroke holding, a plain SAI cylinder suffices. For this non-standard 900mm stroke, the 32mm rod thread and large bore provide excellent side-load resistance, but an external guide is still recommended for the long unsupported span.
Replacement matching requires a single-rod configuration, 125mm bore, 900mm stroke, and PT tapered ports (1/2 cylinder ports, G1/8 enclasp port). It supports BSAI mountings (Basic, FA, FB, CA, CB, CR, LB, TC, TCM1, TCM2). For safety, the clamp unlocks only when cylinder pressures are balanced, preventing abrupt rod jumps. Human-safety-critical loads must use an independent external safety measure.
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 BSAI125X900S FAQ
It provides a static holding force of 8600 N. The clamp is bidirectional and spring-applied, meaning it secures the rod at any position along the 900mm stroke without needing continuous air pressure.
The clamp only locks after the cylinder has stopped and cannot brake a moving rod. To release it safely, air pressure on both sides of the piston must be balanced via the G1/8 enclasp port; otherwise, the rod can jump abruptly.
Related AirTAC Lock & Standard Cylinders
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