Abstract: A counter-element for processing a material by means of ultrasound, the counter-element having a sealing surface, the sealing surface having a welding portion which is at least partially concavely curved. The sealing surface has a feed-in portion which is arranged adjoining the weld portion and is either not curved or is concavely curved with a radius of curvature that is larger than the radius of curvature of the welding portion.

Abstract: The cutting of fibrous material which does not melt easily is effected to avoid the unravelling of cut edges, using ultrasonic or laser beam techniques. The method includes (a) applying a thermoplastic powder material to the cutting region, and (b) applying thermal shock to the localised area, sufficient to destroy the fibres of the material, and melt the powder on either side of the cut, and (c) pressing the cut edges while the fused thermoplastic powder is still soft. Woven or non-woven fabrics have tendency to unravel, after cutting, and normally require a sewn hem. The method of the invention disposes of the sewn hem, and provides a thermo-cutting technique applicable to non-fusible or non-thermoplastic fibres.

Abstract: The present invention relates to an apparatus for producing a gathered material, wherein the material consists of two material web portions and a thread positioned between the material web portions and the two material web portions are connected to one another at two connecting surfaces, wherein the thread is disposed between the two connecting surfaces such that the thread is connected to the material web portions, wherein the apparatus comprises a sonotrode having a first sealing surface and a counter tool having a second sealing surface, wherein the counter tool is cylindrical with a lateral surface and a cylinder axis and the second sealing surface is disposed on the lateral surface, wherein the sonotrode and the counter tool are disposed with respect to one another in a processing position such that the material web portions and the thread can be guided through a gap formed by the first and the second sealing surface in a feed direction tangential to the lateral surface of the counter tool.