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