An upper retaining member is linked to the upper ramp and is movable into and out of the sheet feed plane in alternating {HEAD ~ relation} to {TAIL ~ the upper ramp} 
to
An upper retaining member is linked to the upper ramp and is movable into and out of the sheet feed plane in alternating { HEAD ~ relation } to { TAIL ~ the upper ramp }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL