The sliding frames are provided for movement at an angle of 120 in {HEAD ~ different directions} perpendicular to {TAIL ~ the pitch}, respectively 
perpendicular to
The sliding frames are provided for movement at an angle of 120 in { HEAD ~ different directions } perpendicular to { TAIL ~ the pitch } , respectively
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH