Bonding objects together

A connector for being secured to a first object that comprises a thermoplastic liquefiable material in a solid state, the connector comprising:

• a connector body defining a distal end face and a proximal end face;
• the connector body defining a proximally facing coupling-in structure for being contacted by a tool that couples mechanical vibration energy into the connector body;
• the distal end face extending laterally with respect to a proximodistal anchoring axis, the distal end face being equipped to be pressed against the first object for the connector to be secure thereto while the mechanical vibration energy impinges on the connector body for causing a flow portion of the thermoplastic material of the first object to become liquefied and to flow relative to the connector body;
• wherein the distal end face comprises a plurality of laterally spaced openings, the openings being shaped to receive a flow of the thermoplastic material;
• wherein the laterally spaced openings each define an undercut structure with respect to proximodistal directions, whereby the thermoplastic material, after resolidification, secures the connector to the first object by a positive-fit connection between the undercut structure and the thermoplastic material;
• the connector further comprising a mounting structure for securing a further object to the first object.