{HEAD ~ The tines} 38 are {TAIL ~ solid, rigid structures} in the embodiment shown in FIGS 2 and 4, but may be brushes or a similar, somewhat flexible structure which will effectively dislodge obstructions which blind the screen 30 
are
{ HEAD ~ The tines } 38 are { TAIL ~ solid , rigid structures } in the embodiment shown in FIGS 2 and 4 , but may be brushes or a similar , somewhat flexible structure which will effectively dislodge obstructions which blind the screen 30
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL 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 OTH OTH OTH OTH OTH