The adjustably displaceable frame member 17 is constituted by a flat bar member 38 having a flat support surface and {HEAD ~ a right angle rear plate} 39 spaced rearwardly of {TAIL ~ the forward edge} of the flat support bar 38 
The adjustably displaceable frame member 17 is constituted by a flat bar member 38 having a flat support surface and { HEAD ~ a right angle rear plate } 39 spaced rearwardly of { TAIL ~ the forward edge } of the flat support bar 38
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH