The head is shaped to define a channel for receiving an exposed margin or flange of {HEAD ~ a hinge mount} to rigidly engage {TAIL ~ the hinge} 
The head is shaped to define a channel for receiving an exposed margin or flange of { HEAD ~ a hinge mount } to rigidly engage { TAIL ~ the hinge }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL