Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R
The AirTAC Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R is a single acting, pull type (spring extend) pen-size mini cylinder with direct front-cover mounting (M4×0.7 thread). A single air port drives the pull stroke on a Ø8mm bore, 40mm stroke; the return spring resets the rod when air is released.
- BoreØ8 mm
- Stroke40 mm
- Port sizeM5×0.8
- Front-mount threadM4×0.7
- Acting typePull, single acting
- ReturnSpring
About the Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R
The AirTAC PTBR8X40R is a JIS pen-size single-acting pull cylinder with a 40 mm stroke. Air entering the M5x0.8 port retracts the rod, while an internal spring pushes it back out. If air pressure drops, the spring forces the rod to its extended position, providing a fail-safe extended state for tensioning or return-to-home tasks. It yields about 12.4 N of net pull at 0.5 MPa.
This compact actuator features a SUS316L stainless barrel and a slim body suited for tight jigs. You bolt it directly to a fixture via the M4x0.7 front-cover thread, keeping a single inline plumbing line through the R axial inlet. A fixed TPU bumper cushions the stroke ends. Because pull acts on the smaller rod-side area, this 8 mm bore generates lower force than a matching push cylinder.
Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R Technical Specifications
| Model | Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R |
|---|---|
| Series | PTBR JIS pen-size front-mount cylinder |
| Bore size | Ø8 mm |
| Rod diameter | Ø4 mm |
| Stroke | 40 mm |
| Acting type | Single acting, pull type (spring extend) |
| Front-mount thread | M4×0.7 |
| Port size | M5×0.8 |
|---|---|
| Operating pressure | 0.2 – 0.7 MPa |
| Proof pressure | 1.2 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 50 – 800 mm/s |
| Return | Return spring (pull by air) |
| Max standard stroke | Up to 60 mm |
The spring holds the rod extended; applying air retracts it, and removing air lets the spring push the rod back out. Front cover carries the mounting thread (M4×0.7); barrel is SUS316L. Forces below are NET spring-deducted values. Confirm against the product label.
Net Pull Force (Ø8mm)
| Pressure | Net pull force |
|---|---|
| 0.5 MPa | 12.4 N |
| 0.7 MPa (max) | 19.9 N |
These are usable pull forces after the return spring is subtracted, from the AirTAC single-acting thrust table. Minimum operating pressure is set by the spring, so this model needs at least the lower pressure shown to move.
Model Code: Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R
| PTBR | JIS pen-size front-mount single acting, pull type (spring extend) series. |
|---|---|
| 8 | Bore size in mm. |
| ×40 | Stroke length in mm. |
| S | Built-in magnet for magnetic-switch position sensing (omit = no magnet). |
| R | Back cover: R axial inlet (bore-dependent). |
Mounting: direct front-cover thread (M4×0.7). Related PBR-family variants: PBR (double acting), PSBR (single-acting push).
Where the Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R Is Used
Tensioning Jig
Applies a steady pull on light materials during assembly. The spring keeps the part taut and safely extended if the air supply stops.
Retract-to-Open Gate
Uses the direct M4x0.7 front thread to mount a small diverter. Air pulls the gate closed, and loss of pressure lets the spring push it open.
Hold-Down Clamp
Pulls a lightweight workpiece against a fixture. The fail-safe extended state lifts the clamp automatically on air loss for safe loading.
Is the Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R the Right Cylinder?
When sizing this model, plan for a safe working load of roughly 7 N, which is about 60 percent of the 12.4 N net pull at 0.5 MPa, to account for seal friction. Stepping down to a 6 mm bore gives 7.1 N, while moving up to a 10 mm bore provides 23.5 N. This 8 mm bore offers a balanced middle ground for light tooling.
The spring requires a minimum 0.2 MPa pressure before motion begins. Remember the thin 4 mm rod is built for coaxial thrust, so over this 40 mm stroke you should add an external guide to prevent side load. Confirm your ordering code includes the R axial inlet and the M4x0.7 direct front mount.
Quick checklist
- ✓ Net pull force at your working pressure
- ✓ Bolt directly through the front cover (M4×0.7)
- ✓ Only one air line / solenoid needed
- ✓ Fail-safe extend on air loss
- ✓ Magnet (S) for sensors?
- ✓ Stroke ≤ 60 mm (single-acting limit)
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.2 – 0.7 MPa operating pressure.
- check Allow for spring force in the stroke direction.
- check Match bolt size and engagement to the front thread.
- check Do not add an external return mechanism.
- check Keep the load coaxial; avoid side load on the thin rod.
Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X40R FAQ
It provides 12.4 N of net pull at 0.5 MPa and 19.9 N at the 0.7 MPa maximum. Because it is spring-extended, a minimum 0.2 MPa is required to overcome the spring and retract the rod. The spring holds the rod extended on air loss.
It mounts directly via the M4x0.7 thread on the front cover, requiring no separate bracket. Air plumbing enters inline through the R axial back cover inlet. The SUS316L stainless barrel provides corrosion resistance in tight spaces.
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Related AirTAC PTBR Pen-Size Cylinders
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