Folding bellows
At our site in Ostermünchen near Rosenheim, tools and components are being produced under one roof. Our own toolmaking department manufactures the molds in-house, from CAD design to the production tooling. From there, we produce your folding bellows to size, precisely tailored to the lift, space requirements, and load of your application.
- Customised production
- Batch sizes 1 to 1 million units.
- Express production from 2 weeks
- 100% Reliability & proactivity
Possible variants for Your folding bellows
A custom-made folding bellows accommodates short overhangs with just one fold. Therefore, it is significantly more compact than a bellows with multiple folds at the same diameter. It is particularly suitable for applications with limited space where components must still be reliably protected from dirt, dust, and liquids.
The upper and lower ends have the same diameter, while the fold curves outward in a round or pointed manner.
Cylindrical folding bellows
The two bushings have different diameters and connect housings with a shaft or ball stud. The applied bend can also compensate for tilt angles in addition to the lifting movement.
Conical folding bellows
One end of the folding bellows is closed and can serve as an operating surface in the sense of a button or as a protective surface.
Folding bellows with base
The height of the fold is very flat in relation to the diameter and is uniform in terms of radial offset and vibration.
Flat folding bellows
Properties of Folding bellows
With small lifting and tilting movements in confined space, individual folds have advantages over a design with multiple folds.
- Short installation length: The working distance is contained in just one fold, which means that the bellows is only slightly longer in its compressed state than its two connecting loops.
- No folding contact during tilting movement: Without subsequent folds that contact each other on the inside of the sheet, no wear occurs on the bellows wall.
- Foldable without guide rail: A low build height does not shift to the left or right under axial load and therefore requires neither support rings nor a guide rail.
- Simplified tool construction: A single cut-out simplifies the demolding of the core, which also makes a folding bellows economical as a custom-made product in smaller batches.
made to measure or drawing
- In-house toolmaking: moulds are created internally, with no external waiting times
- Express production possible: first samples already available in 2–3 weeks
- Flexible sizes and quantities
- Custom production from single items to large-scale series
Materials
for folding bellows
The raw material of the custom-made folding bag not only influences the mechanical properties, but also the chemical and thermal properties. Therefore, we assist you in selecting the appropriate material for your application.
Chloroprene withstands lubricants as well as ozone and weathering, and is used outdoors between -40 °C and +100 °C.
NBR rubber is used for applications at temperatures from -30 °C to +110 °C and is resistant to mineral oil-based fats and hydraulic oils.
An in-folding bellows made of HNBR combines the oil resistance of NBR with a wide temperature range up to +150 °C.
Due to its ozone and hot water resistance up to +130 °C, EPDM is used for compensators on ventilation and water pipes as well as outdoor covers.
VMQ is applicable in temperatures ranging from -50 °C to +220 °C and is also easy to manufacture in compliance with FDA regulations and is biocompatible for applications in medical and food technology.
Infill bellows made of fluoroplastic rubber can also be installed when exposed to fuels or chemicals at high temperatures up to +220 °C.
With large quantities, TPE shrink tubes can also be used economically, but only if no special resistances are required.
Natural rubber has high elasticity and is resistant to tearing, but is not suitable for applications in oily or greasy environments.
You have questions about
Folding bellows?
We have answers!
When is a folding bellows useful compared to multiple folds?
A folding bellows is useful when limited movements occur between two connection points and the area in between needs to be protected from dirt, dust, or moisture. The individual folds form the moving zone. Although the folding bellows only offers a limited range of movement and lift, it requires comparatively little space. A bellows with multiple folds is especially useful when larger lifts are required, as the movement can be distributed over several folds.
What movements can an inflatable mattress compensate for?
Depending on its geometry, a folding bellows can accommodate axial movements caused by stretching and bending, as well as limited lateral displacements between the connections. A lateral displacement occurs, for example, when the two connection points are no longer on the same axis. Angular movements can also be realized with a correspondingly designed geometry of the folding bellows. If several directions of movement occur simultaneously, they must be evaluated together, since a axially stretched bellows has different deformation conditions than a bellows in its initial position.
How is the potential lift of a folding bellows determined?
The usable axial stroke results from the difference between the maximum and minimum installation length or the distance between the connection surfaces. Therefore, the shortest and longest positions in operation as well as the connection diameters are required for the design. Subsequently, it is checked whether the fold can accommodate this distance within the available space. In the extended position, it must not be stretched beyond its limits, and in the contracted position, an unacceptable deformation and high friction must be avoided. Additionally, lateral movements, installation tolerances, and the load caused by repeated folding must be taken into account.
How do the fold geometry and the wall thickness affect flexibility?
The fold geometry determines how the folding bellows deforms when being compressed, stretched or laterally deflected. Fold depth, flank shape and transition radii influence the available path of movement and the distribution of deformation. Brute transitions can increase local stress, especially at the transitions between the movable fold and the rigid connection area. For the wall thickness, it applies that thinner wall areas usually deform more easily, while thicker wall thicknesses increase the deformation resistance. However, a very thin wall is not a general design goal, since the manufacturing effort is technically demanding at wall thicknesses below 1 mm and is associated with higher costs.
How can the connections of an accordion bellows be fastened and sealed?
Depending on the installation situation, the connection areas can be designed, for example, as bundles for securing with a hook, as suitable contours for a groove recess or as flange connections for screw-on connections. Furthermore, connections on metal or plastic can be directly bonded together during vulcanization.
