| 摘要 |
At least one elastic component (13, 14) is fitted between the layers (2,4) and arranged in a curve around a number of the welding areas. It is firmly locked between adjoining welding areas without being connected to any of the layers (2,4). The pattern of welding areas comprises a two-dimensional system of straight or curved columns and rows of welding areas and the at least one elastic component (13, 14) in the stretched state describes a zigzag-type curve around the welding areas in the columns and/or rows in the two-dimensional system. - The curve described by the elastic component has an amplitude which is essentially constant along the whole of its length but is greater at its end parts than in the section between the end parts. The elastic component consists of a non-weldable elastic material. |
