Electroplating apparatus for simultaneously and uniformly electroplating inside surfaces of annular bodies

Claim 1

An electroplating apparatus for simultaneously and uniformly electroplating the inside surfaces of a plurality of annular bodies placed upon one another so that their central bores are registered comprising: an upright anode about which said annular bodies are to be placed with the inner surfaces equi-distantly spaced from the outer surface of said anode to thereby define therebetween an annular passage; a plurality of seats respectively separating adjacent ones of said annular bodies to electrically insulate the same from each other; means for forcing an electrolyte through said passage; an elongated cathode conductor for applying a negative potential to said annular bodies; said cathode conductor being substantially vertical and constituting a single member having a considerable intrinsic resistance, said cathode conductor having individual means along its length to apply a different negative potential to each of said annular bodies with the negative potential increasing in the direction of flow of the electrolyte, so that the effective electric current flowing between said anode and the respective annular body is substantially equal even though the electric conductivity of the electrolyte differs along said passage due to the generation of gases in the electrolyte.