When {TAIL ~ the knob} is pressed in a direction indicated by an arrow Pf, the press switch 8 makes {HEAD ~ a stroke} 
When { TAIL ~ the knob } is pressed in a direction indicated by an arrow Pf , the press switch 8 makes { HEAD ~ a stroke }
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD