At the same time, {HEAD ~ the tightening system} affixes {TAIL ~ the clamping lock} inside the beam 
affixes
At the same time , { HEAD ~ the tightening system } affixes { TAIL ~ the clamping lock } inside the beam
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH