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