The pins may be engaged into {HEAD ~ the notches} of the base for securing {TAIL ~ the plate} at the vertical position 
for securing
The pins may be engaged into { HEAD ~ the notches } of the base for securing { TAIL ~ the plate } at the vertical position
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH