DuckCorp Dico

Found one definition

1.                 From English - German Ding/FreeDict dictionary ver. 1.9-fd1:
                   
   
   
                   
                     
   riddlers /ɹˈɪdləz/
   Rüttelsiebe <pl>, Schüttelsiebe <pl>, Rättersiebe <pl>, Rätter <pl>, Durchwurfsiebe <pl>, Durchwurfgitter <pl>
      Synonyms: shaking screens, riddle screens, riddle sieves, riddle sifters
    see: shaking screen, riddle screen, riddle sieve, riddle sifter, riddler