Air cushions for force application — no hydraulics, no friction.
Our air cushions — also known as flange cushions or short-stroke cylinders — stand out for their robustness and durability. Our TrustTube®s offer particularly good chemical resistance, which makes them attractive for force application, especially in industry.
Why air cushions?
Advantages of air cushions
- Excellent adaptability to different shapes
- Force is distributed evenly across a large area
- Low profile height
- Vibration-damping when operated with gaseous media
- Can also be operated hydraulically
- Reliable force application
- No friction, so no stick-slip effect
- Work reliably even at low pressures
- Air cushions are completely leak-proof
Air cushions in industry
Air cushions are frequently used in industry in place of conventional pneumatic cylinders. For a wide range of applications, we offer air cushions in various shapes, profile heights, mounting options and valve connections.
Our TrustTube®s and PowerCushion®s are made from an extremely robust yet highly flexible fibre-reinforced elastomer fabric. The standard material is NBR. On request, air cushions can also be supplied with an additional coating, e. g. aramid coatings for high-temperature applications.
Another advantage is force transmission across the entire contact area – where the elongated shape is particularly beneficial. Custom designs to customer specification are possible from a single unit.
Air cushions in various designs
We develop and manufacture air cushions in various shapes and designs.
TrustTube® air cushions – for force application
Our TrustTube®s are manufactured at our plant to customer specification, Made in Germany. Every TrustTube® that leaves our production facility is tested accordingly. A test certificate for our TrustTube®s is included.
TrustTube® air cushions are available in graduated widths. The length is freely selectable. The size and position of the valve connection can also be freely chosen.
We are happy to help you select the right air cushion and provide data sheets or CAD data, e. g. in STEP format. We also supply all the tailor-made pneumatic accessories you need – from connection parts to valves, including matching controls and circuit diagrams.
Custom designs to customer specification
Every air cushion is designed for its specific application – from valve position to the operating unit. Three typical configurations:
PowerCushion® air cushions
With our PowerCushion®s we have created a product group specifically for dealers and resellers, for which we can offer corresponding discounts. PowerCushion® air cushions are available in graduated widths, with freely selectable length.
PowerCushion® air cushions are manufactured with a vertical valve connection in G1/4" or horizontal valve connection in G1/8". We also manufacture the clamp plates in steel or stainless steel (1.4301). If you need custom designs or other materials, we offer these through our TrustTube® product line. We are happy to help you select the right air cushion.
If you are interested in becoming a dealer, please get in touch. We also manufacture our air cushions with private label.
Finding the right air cushion
Selecting the right air cushion is a matter of a few parameters:
Selection criteria
- Required stroke
- Required force
- Position of the valve connection
- Need for additional mounting options
- Further requirements, such as chemical resistance, heat resistance and more
Made-to-sample manufacturing
We also manufacture air cushions made to sample. Feel free to reach out and send us, for example, pictures of the air cushion you need.
Kowotec GmbH – Your solution with compressed air!
Technical data & pressure forces
All figures in mm or N, valid for TrustTube® and PowerCushion® air cushions. Custom designs and individual lengths are available on request.
Vertical valve connection
Available in thread sizes G 1/8, G 1/4, G 3/8, G 1/2 and G 1 [inch].
| Cushion width [mm] | 36 | 49 | 60 | 68 | 75 | 90 | 108 | 127 | 150 | 170 | 183 | 206 | 248 | 332 | 412 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clamp plate width (K) | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 25 | 25 | 30 | 30 | 35 | 40 | 40 | 40 |
| Profile height (H) | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 16 | 16 | 16 | 16 | 18 | 18 |
| Max. working stroke (A) | 3 | 7 | 12 | 15 | 20 | 25 | 27 | 30 | 35 | 50 | 55 | 60 | 75 | 100 | 125 |
| Height of effective stroke (F) | 18 | 22 | 37 | 30 | 35 | 40 | 42 | 45 | 50 | 66 | 71 | 76 | 91 | 118 | 143 |
| Non-load-bearing area (N) | 29 | 34 | 44 | 44 | 44 | 48 | 52 | 52 | 52 | 77 | 81 | 90 | 107 | 145 | 215 |
All dimensions in mm. Standard valve connection G1/4″ x 50 mm – for cushion width 36, standard valve connection G1/8″ x 50 mm.
The length of the air cushion as well as the position, size and number of valve connections are selectable. Custom designs are possible.
Installation note for adjacent components
| Thread size | G 1/8″ | G 1/4″ | G 3/8″ | G 1/2″ | G 1″ |
|---|---|---|---|---|---|
| Clearance D [mm] | 10 | 13.5 | 17 | 21.2 | 33.5 |
D = clearance required for adjacent components above the valve connection, depending on thread size.
Pressure forces by stroke height and air cushion width
Achievable pressure force depending on installation width and stroke — as a sizing aid for force calculations.
| Installation width [mm] \ Stroke [mm] | 36 | 49 | 60 | 68 | 75 | 90 | 108 | 127 | 150 | 170 | 183 | 206 | 248 | 330 | 412 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3 | 56.5 | 113.0 | 179.0 | 235.5 | 273.2 | 367.4 | 480.4 | 584.0 | 725.3 | 838.4 | 913.7 | 1055.0 | 1309.4 | 1799.2 | 2232.5 |
| 7 | – | 94.2 | 160.1 | 216.7 | 254.3 | 348.5 | 461.6 | 565.2 | 706.5 | 819.5 | 894.9 | 1036.2 | 1290.5 | 1780.4 | 2213.7 |
| 15 | – | – | 65.9 | 122.5 | 160.1 | 254.3 | 367.4 | 471.0 | 612.3 | 725.3 | 800.7 | 942.0 | 1196.3 | 1686.2 | 2119.5 |
| 20 | – | – | – | – | 113.0 | 207.2 | 320.3 | 423.9 | 565.2 | 678.2 | 753.6 | 894.9 | 1149.2 | 1639.1 | 2072.4 |
| 25 | – | – | – | – | – | 160.1 | 273.2 | 376.8 | 518.1 | 631.1 | 706.5 | 847.8 | 1102.1 | 1592.0 | 2025.3 |
| 27 | – | – | – | – | – | – | 254.3 | 358.0 | 499.3 | 612.3 | 687.7 | 829.0 | 1083.3 | 1573.1 | 2006.5 |
| 30 | – | – | – | – | – | – | – | 329.7 | 471.0 | 584.0 | 659.4 | 800.7 | 1055.0 | 1544.9 | 1978.2 |
| 35 | – | – | – | – | – | – | – | – | 423.9 | 536.9 | 612.3 | 753.6 | 1007.9 | 1497.8 | 1931.1 |
| 40 | – | – | – | – | – | – | – | – | – | 489.8 | 565.2 | 706.5 | 960.8 | 1450.7 | 1884.0 |
| 50 | – | – | – | – | – | – | – | – | – | 395.6 | 471.0 | 612.3 | 866.6 | 1356.5 | 1789.8 |
| 55 | – | – | – | – | – | – | – | – | – | – | 423.9 | 565.2 | 819.5 | 1309.4 | 1742.7 |
| 60 | – | – | – | – | – | – | – | – | – | – | – | 518.1 | 772.4 | 1262.3 | 1695.6 |
| 75 | – | – | – | – | – | – | – | – | – | – | – | – | 631.1 | 1121.0 | 1554.3 |
| 100 | – | – | – | – | – | – | – | – | – | – | – | – | – | 885.5 | 1318.8 |
| 125 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | 1083.3 |
Values in N at 10 mm effective length and 6 bar pressure (figures may vary due to tolerances).
Important note
When determining the required lifting force by stroke height, the non-load-bearing area must be taken into account when calculating cushion length!
Questions & answers about air cushions
What is an air cushion?
An air cushion (also called a lifting cushion, pressure cushion, flange cushion or pneumatic lifting set) is a fibre-reinforced elastomer sealed at the edges with at least one valve connection. It is filled with compressed air or fluids and used to lift, clamp, grip, push or press loads.
Who manufactures air cushions?
Kowotec GmbH of Kirchhundem manufactures the TrustTube® and PowerCushion® air cushion systems, developed and produced in Germany. Kowotec also develops complete solutions together with its customers.
What are the advantages of air cushions over hydraulics?
Air cushions adapt well to different shapes, distribute force evenly over a large area, require only a low profile height and have a vibration-damping effect when operated with gaseous media. Since no friction occurs, there is no stick-slip effect, and they work reliably even at low pressures. They are also a hydraulic-free force solution and therefore often the more cost-efficient alternative.
What applications are Kowotec air cushions used for?
Kowotec's TrustTube® and PowerCushion® air cushions are used in five application areas: lifting, clamping, gripping, pushing and pressing. Among other things, they are used in mechanical engineering, e. g. as traverses for stripping rolling media or as bottle grippers.
Where do Kowotec's air cushions come from?
All TrustTube® and PowerCushion® air cushions are Made in Germany at the Kowotec plant in Kirchhundem. The company is also certified to ISO 9001:2015 and has more than 20 years of experience in air cushion and lifting bag technology.
Does Kowotec also offer custom-made products?
Yes. Kowotec develops custom air cushions from as little as a single unit and manufactures individual designs to customer specification, including special casings or multi-chamber air cushions with separately operable pressure chambers. CAD data, drawings and parts lists are provided for the collaboration.
What is the minimum profile height of Kowotec air cushions?
Kowotec manufactures air cushions with a profile height of just 7 mm, enabling very space-saving integration into existing designs.
How does Kowotec ensure the reliability of its air cushions?
Every air cushion undergoes a pressure test immediately before shipping to ensure its reliability. In addition to its own range, Kowotec also offers Vetter lifting bags with a lifting force of up to 171.8 tonnes.
Further information
Which air cushion fits your application?
Whether a standard design or a custom build from a single unit – we provide personal advice, supply CAD data and work with you to develop the right solution.
Get in touch now