Airtac SAILB Rear Lock Cylinder SAILB63X125S
The AirTAC Airtac SAILB Rear Lock Cylinder SAILB63X125S is a genuine double-acting ISO 15552 profile cylinder with a Ø63mm bore, 125mm 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.
- BoreØ63 mm
- Stroke125 mm
- Port sizeG3/8
- Lock positionBack cover
- Rod threadM16×1.5
- UnlockAir + manual
About the Airtac SAILB Rear Lock Cylinder SAILB63X125S
The AirTAC SAILB63X125-S is a double-acting ISO 15552 profile cylinder featuring a built-in mechanical lock in the back cover. Because the lock is spring-applied and air-released, cutting the release air forces a lock pin into the carbon steel rod, securely holding the load at the retracted stroke end without consuming live pressure. In this 63mm bore class, the cylinder generates 1559N of push thrust and 1402N of pull thrust at 0.5 MPa, making it highly capable for medium-duty holding tasks.
Unlocking is achieved automatically by supplying air to the release port or by using the manual release lever for maintenance. The integrated magnet (-S) allows for precise end-of-stroke detection using AirTAC CMSE reed switches or DMSE solid-state electronic sensors. A notable design feature is the variable air cushion: the locker end utilizes a shorter 21mm cushion stroke compared to the 30mm cushion at the free end, ensuring compact deceleration without interfering with the locking mechanism.
Airtac SAILB Rear Lock Cylinder SAILB63X125S Technical Specifications
| Model | Airtac SAILB Rear Lock Cylinder SAILB63X125S |
|---|---|
| Series | SAIL ISO 15552 cylinder with lock |
| Bore size | Ø63 mm |
| Stroke | 125 mm |
| Acting type | Double acting, with lock |
| Port size | G3/8 |
| Rod thread | M16×1.5 |
| 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 – 800 mm/s |
| Cushion | Adjustable (30 mm free end / 21 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 (Ø63mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 1559 N | 1402 N |
| 0.7 MPa | 2182 N | — |
| Max (@1.0 MPa) | 318 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 SAILB63X125S Is Used
Vertical Lift Safety
Secures a raised vertical load in the retracted position instantly upon air pressure loss, preventing sudden drops on lifting platforms.
Clamp and Hold
Maintains firm clamping force on a machined workpiece at the end of the stroke without continuously consuming compressed air.
Gate Positioning
Locks heavy safety gates or machine guards in the closed position mechanically, requiring an active air signal to release.
Is the Airtac SAILB Rear Lock Cylinder SAILB63X125S the Right Lock Cylinder?
Select this 63mm bore model when an application requires safely holding a load at the fully retracted position during a power or air loss event. If your setup demands higher force, stepping up to the 80mm bore yields 2513N of push force at 0.5 MPa; conversely, dropping to the 50mm bore reduces the push force to 982N. Choose this SAILB configuration specifically when the rod-in state must be secured, whereas the SAILF variant is necessary for holding the extended rod-out position.
It is critical to understand that this unit functions as a static holding lock that engages only after the piston stops at the stroke terminal, not as a dynamic brake for a moving rod. If your process requires clamping at an arbitrary mid-stroke point, the AirTAC BSAI clamp-lock cylinder is the correct choice instead. For valve selection, avoid fast-exhaust valves and use an independent-exhaust solenoid valve, as back-pressure on the locker side can inadvertently release the lock. When matching replacements, verify the 125mm stroke, back locker position, PT tapered port threads, and the -S magnet. Always add an independent safety measure if human safety relies on the suspended load.
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 SAILB63X125S FAQ
At an operating pressure of 0.5 MPa, the 63mm bore generates 1559N of push force and 1402N of pull force. At the maximum operating pressure of 1.0 MPa, the maximum push force reaches 318 kgf.
The lock is spring-applied and air-released, meaning it engages automatically to hold the rod at the retracted stroke end when release air is cut off. It is a static hold that engages after the cylinder stops, not a mid-stroke clamp or dynamic brake. It can be unlocked via an automatic air signal or a manual release lever.
Related AirTAC Lock & Standard Cylinders
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