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