The entrainment means 19 is thus secured to {HEAD ~ the cross plate} 20, which constitutes {TAIL ~ an oscillating member} 
constitutes
The entrainment means 19 is thus secured to { HEAD ~ the cross plate } 20 , which constitutes { TAIL ~ an oscillating member }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL