A method for manufacturing a hub ring provided on at least one of inner and outer circumferences of a disc-type filter including: forming a plurality of slits on an annular plate having a central opening at a position on one of inner and outer circumferential edge portions of the annular plate, the...http://www.google.ca/patents/US5755034?utm_source=gb-gplus-sharePatent US5755034 - Method for manufacturing a hub ring for a filter
