Apparatus and method for producing a gathered or gatherable material

Apparatus for producing a gathered or gatherable material, wherein the material consists of at least two material web portions and at least one thread positioned between the material web portions,

• wherein the two material web portions are connected to one another at at least two connecting surfaces, wherein the thread is disposed between the two connecting surfaces such that the thread is connected to the material web portions in such a way that there is a form-locking connection between the thread and the material web portions in a first and a second direction, wherein the two directions are oriented perpendicular to one another, 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 first cylinder axis, the second sealing surface is disposed on the lateral surface and is rotatable about the cylinder axis, 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,
• characterised in that the sonotrode comprises at least one groove which is oriented in the feed direction, and wherein the second sealing surface does not comprise a groove for partially receiving the at least one thread.