Patent ID: 8756790

Claim:
A method for joining a plurality of objects, the method comprising the steps of: providing a plurality of joining elements, each joining element comprising a proximal end of a thermoplastic material and a distal end of a thermoplastic material; arranging the objects and the joining elements relative to one another so that the distal end of each joining element is positioned in a recess of one of the objects to be joined and the proximal end of each joining element is positioned in a recess of another one of the objects to be joined, wherein portions of each of the joining elements that are positioned in the recess are chosen to have a smaller diameter than the recess and wherein the distal end and the proximal end each are in contact with a recess bottom end face simultaneously, with a gap between these objects; while the proximal and distal ends are in contact with the recess bottom end faces, forcing the objects to be joined against each other while coupling mechanical vibrations into at least one of the objects to be joined and thereby simultaneously liquefying at least a part of the thermoplastic material of the proximal end and of the distal end of each joining element and allowing the liquefied material to infiltrate into pores or surface unevennesses or openings of surfaces of the recesses; continuing the steps of forcing and of coupling the mechanical vibrations into at least one of the objects until the gap is closed; and stopping the mechanical vibrations and allowing the liquefied material to re-solidify; thereby anchoring the joining element ends in the respective recesses of the objects.