The sensor assembly preferably includes a U shaped support bracket centered about the elongated opening and {HEAD ~ a pair} of {TAIL ~ sensor block members} secured to the support bracket in facing relation 
of
The sensor assembly preferably includes a U shaped support bracket centered about the elongated opening and { HEAD ~ a pair } of { TAIL ~ sensor block members } secured to the support bracket in facing relation
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH