a securing plate having {HEAD ~ plurality} of notches, mounted to {TAIL ~ said second free end} of said second arm 
mounted to
a securing plate having { HEAD ~ plurality } of notches , mounted to { TAIL ~ said second free end } of said second arm
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH