Airtac SAILB Rear Lock Cylinder SAILB125X700
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB125X700 is a genuine double-acting ISO 15552 profile cylinder with a Ø125mm bore, 700mm stroke and a built-in spring-applied, air-released mechanical lock in the back cover — it holds the load at the retracted (rod-in) stroke end even when air is lost.
- BoreØ125 mm
- Stroke700 mm
- Port sizeG1/2
- Lock positionBack cover
- Rod threadM27×2
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB125X700
The AirTAC SAILB125X700 is a double-acting ISO 15552 profile cylinder featuring a spring-applied, air-released mechanical lock built into the back cover. This lock engages automatically when the piston reaches the retracted stroke end, securely holding a load in place without requiring continuous live air pressure. It delivers 6136N of push force and 5734N of pull force at 0.5 MPa, making it well-suited for heavy-load positioning.
Unlike a plain SAI cylinder, this model provides true static load holding upon power loss. The variable air cushion at the locker end is 24mm, intentionally shorter than the 40mm cushion at the free end, to accommodate the locking mechanism. The standard carbon steel rod provides robust durability, and the PT tapered port threads ensure a reliable, sealed connection.
Airtac SAILB Rear Lock Cylinder SAILB125X700 Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB125X700 |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø125 mm |
| Stroke | 700 mm |
| Acting type | Double acting, with lock |
| Port size | G1/2 |
| Rod thread | M27×2 |
| Lock type | Spring-applied, air-released (back cover) |
|---|---|
| Unlock | Automatic (air) & manual |
| Operating pressure | 0.15 – 1.0 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Cushion | Adjustable (40 mm free end / 24 mm lock end) |
| Max stroke | Up to 1500 mm |
Specifications follow the official AirTAC SAIL datasheet (ISO 15552). Confirm against the product label before installation. Port options: PT / G.
How the Lock Holds
The lock is spring-applied and air-released: a spring drives a lock pin into the rod when the release air is removed, so the load is held at the retracted (rod-in) stroke end without live pressure. Supply air to the release port to unlock automatically, or use the manual release lever.
The lock engages only when the piston reaches the stroke terminal on the back-cover side — it is a static end-of-stroke hold, not a mid-stroke clamp and not a moving-rod brake. For locking at any position along the stroke, choose a BSAI clamp-lock instead.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
Cylinder thrust is separate from the lock's holding capability. Actual usable force is lower than theoretical due to friction and back-pressure — size with a margin.
Where the Airtac SAILB Rear Lock Cylinder SAILB125X700 Is Used
Vertical Power-Loss Hold
Maintains the retracted position of heavy vertical lifts automatically if air pressure drops, preventing sudden load crashes.
Heavy Clamp Retention
Keeps a workpiece clamped securely at the end of the stroke during machining operations without consuming continuous compressed air.
Safety Gate Locking
Holds safety gates and heavy access panels firmly closed at the retracted stroke end until the release air is actively supplied.
Is the Airtac SAILB Rear Lock Cylinder SAILB125X700 the Right Lock Cylinder?
Choose this 125mm bore when a 100mm bore (providing 3927N push at 0.5 MPa) lacks sufficient thrust, or step up to a 160mm bore (10053N push at 0.5 MPa) if your load exceeds 6136N. Select the SAILB configuration when the load must be safely held at the rod-in retracted position; choose a SAILF model if the load must be held at the extended rod-out position. If your application requires locking at an arbitrary mid-stroke point rather than a stroke end, the BSAI clamp-lock cylinder is the correct choice instead.
Because this lock is a static holding device that engages only after the cylinder stops, it will not brake a moving rod. Avoid using fast-exhaust valves, as back-pressure on the locker side can unintentionally release the lock; always use an independent-exhaust solenoid valve. For any safety-critical load that could endanger human operators if it drops, add an independent mechanical safety measure. At 700mm stroke, use appropriate guiding mechanisms to prevent excessive side-load wear on the rod seals.
Quick checklist
- ✓ Hold needed at the retracted (rod-in) end?
- ✓ Or lock anywhere → use BSAI
- ✓ Independent-exhaust valve fitted
- ✓ Port/thread type (PT/G)
- ✓ Extra safety measure for people
Airtac SAILB Rear Lock Cylinder SAILB125X700 FAQ
At 0.5 MPa operating pressure, the 125mm bore provides 6136N of push force and 5734N of pull force. At the maximum 1.0 MPa pressure, it delivers a maximum push force of approximately 1251 kgf.
The lock is spring-applied and air-released, located in the back cover so it holds the rod only at the fully retracted stroke end. It is a static hold that engages after the cylinder stops, not a mid-stroke clamp or dynamic brake. Unlocking is achieved automatically by supplying release air or manually via the release lever.
Related AirTAC Lock & Standard Cylinders
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