The retaining elements engage {HEAD ~ adjacent and undercut channels} formed by the webs and are tightened against two adjacent webs of the support shaped section by a rotationally actuated, transverse tightening system crossing the three retaining elements through {TAIL ~ mutually flush clearances} 
The retaining elements engage { HEAD ~ adjacent and undercut channels } formed by the webs and are tightened against two adjacent webs of the support shaped section by a rotationally actuated , transverse tightening system crossing the three retaining elements through { TAIL ~ mutually flush clearances }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL