A pin is mounted downwardly on the flatbed unit, such that {HEAD ~ the pin} can be received in {TAIL ~ the slot} for connecting and disconnecting the flatbed unit from the tractor unit 
received in
A pin is mounted downwardly on the flatbed unit , such that { HEAD ~ the pin } can be received in { TAIL ~ the slot } for connecting and disconnecting the flatbed unit from the tractor unit
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH