The pieces are unloaded and fed into sorting machines.
( ( The pieces ) ( ( are ( ( ( unloaded and ) fed ) ( into ( sorting machines ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS pieces)) (VP (VBP are) (VP (VBN unloaded) (CC and) (VBN fed) (PP (IN into) (NP (VBG sorting) (NNS machines))))) (. .)))
Pieces are unloaded and fed into machines to sort 
( Pieces ( are ( ( ( unloaded and ) fed ) ( into ( machines ( to sort ) ) ) ) ) )
(ROOT (S (NP (NNP Pieces)) (VP (VBP are) (VP (VBN unloaded) (CC and) (VBN fed) (PP (IN into) (NP (NP (NNS machines)) (PP (TO to) (NP (NN sort)))))))))