Airtac BSAI Locking Clamp Cylinder BSAI125X400S
The AirTAC Airtac BSAI Locking Clamp Cylinder BSAI125X400S is a genuine double-acting ISO 15552 cylinder with a Ø125mm bore, 400mm 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
- Stroke400 mm
- Cylinder portG1/2
- TypeSingle rod (BSAI)
- Enclasp portG1/8
- Rod threadM27×2
About the Airtac BSAI Locking Clamp Cylinder BSAI125X400S
The AirTAC BSAI125X400-S is a double-acting ISO 15552 profile cylinder equipped with a spring-applied, air-released clamp-lock. It delivers a massive 8590 N of thrust at 0.7 MPa and uses a bidirectional enclasp mechanism to hold the load at any position along its 400 mm travel. The clamp provides a static holding force of 8600 N. You must size the holding force against your static load, as the 8600 N clamp capacity is a distinct quantity from the 8590 N cylinder thrust.
This model includes a -S magnet for CMSE reed and DMSE solid-state sensors. The lock engages only after the piston stops; it cannot brake a moving rod. The variable air cushion decelerates the piston near stroke ends, but the clamp is the true holding mechanism. Unlocking requires balanced air pressure via the G1/8 enclasp port to prevent abrupt rod movement.
Airtac BSAI Locking Clamp Cylinder BSAI125X400S Technical Specifications
| Model | Airtac BSAI Locking Clamp Cylinder BSAI125X400S |
|---|---|
| Series | BSAI ISO 15552 clamp-lock cylinder |
| Bore size | Ø125 mm |
| Stroke | 400 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 BSAI125X400S Is Used
Vertical Load Holding
Secures heavy vertical payloads at any point in the 400 mm travel, preventing gravity-driven drops during power loss.
Machining Position Lock
Clamps the 32 mm rod rigidly with 8600 N to hold a workpiece steady for mid-stroke machining or inspection tasks.
Emergency Safety Hold
Acts as a fail-safe enclasp that engages upon air loss to freeze the piston instantly once motion ceases.
Is the Airtac BSAI Locking Clamp Cylinder BSAI125X400S the Right Clamp-Lock?
Choose this 125 mm bore if your application requires exceptional thrust and holding power, stepping up from the 100 mm bore which offers 5497 N thrust at 0.7 MPa and a 5500 N holding force. Select a plain SAI cylinder if you only need end-of-stroke positioning without mid-stroke clamping. Choose BSAI over SAIL when you need to lock at any position rather than just at the stroke end.
This 400 mm stroke exceeds 300 mm, so an external guide is recommended to handle side loads despite the robust 32 mm carbon steel rod and M27x2 thread. The clamp locks after the cylinder stops and is not a dynamic brake; safety-critical applications need an independent measure. Replacement requires a single-rod 125x400 configuration, PT port threads, and mounting from the BSAI set: Basic, FA, FB, CA, CB, CR, LB, TC, TCM1, or TCM2.
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 BSAI125X400S FAQ
The clamp-lock provides a static holding force of 8600 N. It engages via a spring-applied mechanism to hold the rod bidirectionally at any position, but only after the piston has stopped moving.
The clamp is released by supplying air to the G1/8 enclasp port. You must balance the air pressures on both sides of the piston before unlocking, otherwise the rod can jump abruptly. The lock is not a dynamic brake.
Related AirTAC Lock & Standard Cylinders
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