FIG 6 also depicts a frame top extension 126 having {HEAD ~ a hole} 128 positioned adjacent {TAIL ~ the pivoting ball support top extension hole} 130, such that a pin or lock can be inserted simultaneously through both holes 128,130, thus locking the pivoting ball support face 132 into its first position 
FIG 6 also depicts a frame top extension 126 having { HEAD ~ a hole } 128 positioned adjacent { TAIL ~ the pivoting ball support top extension hole } 130 , such that a pin or lock can be inserted simultaneously through both holes 128,130 , thus locking the pivoting ball support face 132 into its first position
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH