Reference numeral 47 denotes {HEAD ~ an adjusting knob} adapted to adjust {TAIL ~ the downward pressure} applied to the upper feed dog 40 
adapted to adjust
Reference numeral 47 denotes { HEAD ~ an adjusting knob } adapted to adjust { TAIL ~ the downward pressure } applied to the upper feed dog 40
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH