The frame 20 is provided with {TAIL ~ a pair} of {HEAD ~ transverse flanges} 51 which are adapted to overlie a pair of flanges 52 which project from the plate 48 
The frame 20 is provided with { TAIL ~ a pair } of { HEAD ~ transverse flanges } 51 which are adapted to overlie a pair of flanges 52 which project from the plate 48
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH