The pivoting ball support movement prevention means can include a slot in {HEAD ~ the top} of {TAIL ~ the frame}, through which the pivoting ball support top extension protrudes 
of
The pivoting ball support movement prevention means can include a slot in { HEAD ~ the top } of { TAIL ~ the frame } , through which the pivoting ball support top extension protrudes
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH