Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X20SR
The AirTAC Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X20SR 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, 20mm stroke; the return spring resets the rod when air is released.
- BoreØ8 mm
- Stroke20 mm
- Port sizeM5×0.8
- Front-mount threadM4×0.7
- Acting typePull, single acting
- ReturnSpring
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X20SR
The AirTAC PTBR8X20SR is a JIS pen-size single-acting pull cylinder with a 20mm stroke. Air entering the M5x0.8 port retracts the rod, while an internal spring pushes it back out, ensuring a fail-safe extended state upon air loss. It delivers 12.4N of net pull at 0.5MPa and 19.9N at 0.7MPa. Because pulling acts on the smaller rod-side area, this force is lower than the equivalent push cylinder.
You mount it directly via the front-cover M4x0.7 thread, saving space in tight jigs. The SUS316L stainless barrel and Ø4mm rod provide corrosion resistance, while a fixed TPU bumper cushions the stroke ends. The built-in magnet (-S) supports reed or electronic switches, and the R axial inlet keeps plumbing in line.
Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X20SR Technical Specifications
| Model | Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X20SR |
|---|---|
| Series | PTBR JIS pen-size front-mount cylinder |
| Bore size | Ø8 mm |
| Rod diameter | Ø4 mm |
| Stroke | 20 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 PTBR8X20SR
| PTBR | JIS pen-size front-mount single acting, pull type (spring extend) series. |
|---|---|
| 8 | Bore size in mm. |
| ×20 | 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 PTBR8X20SR Is Used
Hold-Down Clamping
Uses spring pressure to keep a delicate workpiece extended and clamped, retracting only when air is applied to release the part.
Wire Tensioner
Maintains constant tension on a filament or wire line with the rod extended, pulling back to slacken the line during machine indexing.
Retract-to-Open Gate
Spring holds a diverter gate open by default for safe product passage, pulling it closed only when the line needs to sort items.
Is the Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X20SR the Right Cylinder?
This 8mm bore provides 12.4N net pull at 0.5MPa. If you need less force, the 6mm bore offers 7.1N; if you need more, the 10mm bore provides 23.5N. Plan for a safe working load of about 7N (roughly 60% of the 0.5MPa rating) to account for seal friction and smooth travel. For vertical lifting, this equates to holding or pulling about 0.6kg with a sane 2:1 safety margin.
Remember the spring requires a minimum 0.2MPa to function. The Ø4mm rod is built for coaxial thrust, so over this 20mm stroke or under off-axis loads, add an external guide to prevent side load. Confirm your front-mount thread matches the M4x0.7 specification, and note the separate M5x0.8 air port.
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 PTBR8X20SR FAQ
The net pull force is 12.4N at 0.5MPa and 19.9N at 0.7MPa (maximum operating pressure). Because it is single-acting pull, the spring requires a minimum of 0.2MPa to move the rod, and the cylinder fails safe to the extended position on air loss.
It mounts directly via the front-cover M4x0.7 thread, separate from the M5x0.8 air port. The -S suffix denotes a built-in piston magnet compatible with AirTAC reed or electronic solid-state switches mounted along the SUS316L barrel.
Authorized Export Seller
Genuine AirTAC parts produced by AirTAC factory.
1-Year Warranty
Covers non-human-caused product damage.
Fast Dispatch
Standard models are processed and dispatched in 3-5 business days.
Fast Reply
Most inquiries answered within 7-8 hours.
Related AirTAC PTBR Pen-Size Cylinders
Request a Quote for Airtac PTBR Single Acting Square Head Compact Cylinder PTBR8X20SR
Send us the quantity and destination. We confirm price, stock and lead time — usually within 7-8 hours.