Nontrepanning nonrotary electrode for electroerosion of metals

Claim 2

An electrode for forming holes in metal workpieces by electroerosion comprising an elongated member having an inactive end adapted for connection to electroerosion apparatus and an opposed active end and at least one internal through passage for dielectric fluid in said member from the inactive to the active end, said passage at least at the active end being helical and generating a segmental area when a cross section is taken through the entire member whose maximum transverse depth extends up to the central axis of said member as a maximum so that substantially no buildup of a central plug due to trepanning will occur as the active end of the electrode is consumed.

Claim 3

The electrode of claim 1 wherein said elongated member comprises an outer tubular member and an inner solid helical core member having diametrically opposed edge portions contacting the inner surface of said tubular member and sides spaced from the inner surface of said tubular member thereby forming at least two internal helical dielectric fluid passages.

Claim 4

The electrode of claim 2 wherein said inner helical core member is coextensive with said outer member.

Claim 5

The electrode of claim 2 wherein said inner helical core member is an elongated helical bar which extends diametrically of the outer member in a transverse direction so that a pair of said segmental areas are generated on both sides of said bar when a cross section is taken through said bar and outer tubular member.

Claim 6

The electrode of claim 4 wherein the thickness of said bar and that of said outer tubular member are substantially the same to produce a substantially cylindrical hole in said workpieces.

Claim 7

The electrode of claim 4 wherein said bar is polygonal in cross section whereby as many helical passages as there are sides to the polygon are formed which generate a multiplicity of said segmental areas when a cross section is taken through said polygonal bar and outer tubular member.

Claim 8

The electrode of claim 4 wherein said bar is triangular in cross section whereby three helical passages are formed which generate three of said segmental areas when a cross section is taken through said triangular bar and said outer tubular member.

Claim 9

The electrode of claim 4 wherein said bar is rectangular in cross section whereby four helical passages are formed which generate four of said segmental areas when a cross section is taken through said rectangular bar and said outer tubular member.

Claim 10

The electrode of claim 4 wherein said bar is square in cross section whereby four helical passages are formed which generate four of said segmental areas when a cross section is taken through said square bar and said outer tubular member.

Claim 11

Electroerosion apparatus comprising a hollow spindle, means to circulate dielectric fluid through said spindle, an electrode, means to removably secure said electrode to said spindle, a workpiece holder, and means applying a direct current between said electrode securing means and said workpiece holder to provide an erosion spark between the active end of said electrode and the workpiece, said electrode being an elonGated member having at least one internal through passage therein for the dielectric fluid, said passage at least at the active end being helical and generating a segmental area when a cross section is taken through the entire member whose maximum transverse depth extends up to the central axis of said member as a maximum so that substantially no buildup of a central plug due to trepanning will occur as the active end of the electrode is consumed.

Claim 12

Electroerosion apparatus comprising a hollow spindle, means to circulate dielectric fluid through said spindle, an electrode, means to removably secure said electrode to said spindle, a workpiece holder, and means applying a direct current between said electrode securing means and said workpiece holder to provide an erosion spark between the active end of said electrode and the workpiece, said electrode being an elonGated member having at least one internal through passage therein for the dielectric fluid, said passage at least at the active end being helical and generating a segmental area when a cross section is taken through the entire member whose maximum transverse depth extends up to the central axis of said member as a maximum so that substantially no buildup of a central plug due to trepanning will occur as the active end of the electrode is consumed.

Claim 13

The combination of claim 10 wherein said elongated member comprises an outer tubular member and an inner solid helical core member having diametrically opposed portions contacting the inner surface of said tubular member and sides spaced from the inner surface of said tubular member thereby forming at least two internal helical dielectric fluid passages.

Claim 14

The combination of claim 10 wherein said inner helical core member is an elongated helical bar which extends diametrically of the outer member in a transverse direction so that a pair of said segmental areas are generated on both sides of said bar when a cross section is taken through said bar and outer tubular member.

Claim 15

The combination of claim 12 wherein said bar is polygonal in cross section whereby as many helical passages as there are sides to the polygon are formed which generate a multiplicity of said segmental areas when a cross section is taken through said polygonal bar and outer tubular member.