{TAIL ~ The cavity} of the rotary button 1 serves for accommodating the bearing for displacing the rotary button 1 in a plane perpendicular to its axis of {HEAD ~ rotation}, which approximately lies in the plane of the page of FIG 1 
{ TAIL ~ The cavity } of the rotary button 1 serves for accommodating the bearing for displacing the rotary button 1 in a plane perpendicular to its axis of { HEAD ~ rotation } , which approximately lies in the plane of the page of FIG 1
TAIL TAIL TAIL TAIL TAIL TAIL OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH