a securing rod inserting through {HEAD ~ said bores} into {TAIL ~ said support bars} and being capable of screwing into one notch on said securing plate, thereby locking said supporting shank into one position; and 
a securing rod inserting through { HEAD ~ said bores } into { TAIL ~ said support bars } and being capable of screwing into one notch on said securing plate , thereby locking said supporting shank into one position ; and
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH 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