A system for pre-tensioning a joint comprising a number of threaded elements

A system for pre-tensioning a joint (13) including two or more threaded fasteners (11a-c) by a synchronized tightening of the threaded fasteners. The system comprises two or more torque delivering power wrenches (10a-c) and at least one operation control unit (18) communicating with the power wrenches for control of the operation of each one of the power wrenches, wherein the power wrenches are manually supported battery powered power wrenches each having a wireless communication module, and the operation control unit comprises a wireless communication module (24) for communicating with the wireless communication modules (16a-c) of the power wrenches to thereby receive actual operation data from each power wrench and to deliver relevant operation data to each power wenches to adapt the tightening operation of each power wrench to the actual tightening status of the other power wrench or wrenches to achieve synchronous tightening of the fasteners and even pre-tensioning of the joint. 种用于通过同步拧紧螺纹紧固件而预紧包括两个或更多个螺