Each recess includes a hole in an inner bottom thereof so that {HEAD ~ the two pawls} are pivotably inserted in {TAIL ~ the two holes} by their respective shafts 
are pivotably inserted in
Each recess includes a hole in an inner bottom thereof so that { HEAD ~ the two pawls } are pivotably inserted in { TAIL ~ the two holes } by their respective shafts
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH