The step ladder 3 further comprising {HEAD ~ a bar} slidably attached to at least one of said lower back leg, said upper back leg, and said lock plate, said bar slidable between a first position interfering with {TAIL ~ pivoting} of said lock plate and a second non interfering position 
The step ladder 3 further comprising { HEAD ~ a bar } slidably attached to at least one of said lower back leg , said upper back leg , and said lock plate , said bar slidable between a first position interfering with { TAIL ~ pivoting } of said lock plate and a second non interfering position
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD 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 OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH