each said lock rod has {TAIL ~ a rib portion} extending across {HEAD ~ the upper end} thereof for engagement with said blocking device 
each said lock rod has { TAIL ~ a rib portion } extending across { HEAD ~ the upper end } thereof for engagement with said blocking device
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH