Patent ID: 7402231
Filing Date: 2008-07-22
Classification: C25D

Abstract:
1. A method for partially plating a work for a piston, said work having sliding portions on a skirt portion under a lidded piston crown portion with annular circumferential grooves therearound, and having a boss portion to receive a piston pin, said method comprising the steps of: providing a plating bath filled with an electrolyte and having two anode plates set in position within said plating bath; directly supporting said work on a hanger adapted to immerse said work in said plating bath, said piston crown portion positioned above said skirt portion; providing an electrically insulated shield member directly supported on said hanger, wherein said work is supported on said hanger in such a way as to close said annular circumferential grooves of said piston crown portion while retaining small gap relation with said piston crown portion, wherein the piston crown and the shield member do not contact one another, and said shield member being provided with openings to expose the sliding surfaces of said skirt portion; immersing said work in said plating bath; and depositing a plating metal on said sliding surface on said skirt portion, said hanger supporting said work and said shield member at a position between said two anode plates in said plating bath and in a tilted posture parallel with said anode plates while conducting current between said work serving as a cathode and said anode plates, wherein said work and said shield member are supported by the hanger in a tilted posture before being immersed in the plating bath, during the depositing of the plating metal and after being removed from the plating bath.