the extension member is pivotably attached about {HEAD ~ the rotary shaft} between {TAIL ~ the first position} and the second position, 
between
the extension member is pivotably attached about { HEAD ~ the rotary shaft } between { TAIL ~ the first position } and the second position ,
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH