{HEAD ~ A third improvement} comprises {TAIL ~ a sweepable member} having a chamfered edge in a sweep direction, the edge making an angle of between about 5 8 degrees with the plane of the path 
comprises
{ HEAD ~ A third improvement } comprises { TAIL ~ a sweepable member } having a chamfered edge in a sweep direction , the edge making an angle of between about 5 8 degrees with the plane of the path
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL 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 OTH OTH