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US 4,287,749 AGranted
Tapered extrusion die and method of forming the same
AssigneeFord Motor Company
InventorsBenjamin I. Bachrach, William J. Fuhrman
Life of this patent
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AssigneeFord Motor Company
InventorsBenjamin I. Bachrach, William J. Fuhrman
Estimating the term…
A sleeve having a tapered outer surface is shrink or interference fitted over the outer surface of a die blank in which is formed a central bore, a larger diameter bore and a transition bore therebetween. The diametrical interference between the sleeve and the die blank is effective in producing an elastic deformation of the smaller diameter bore causing it to assume a conical shape. The die blank and sleeve are restrained within a casing and the inner surface of the die is formed by electrical discharge machining, electrical chemical machining or by other known methods. The die casing and sleeve are removed from the die, allowing the release of the stored strain energy of deformation which causes the smaller bore of the die to assume a conical shape tapering radially outwardly from its inner extremity. The sharp corner that results at the innermost end of the smaller bore is removed by lapping a straight-sided tool through the central opening of the die.
A die adapted to form an extrusion made by the method comprising the steps of:
A die blank adapted to form an extrusion made by the method comprising the steps of:
A method of making a die adapted to form an extrusion comprising the steps of:
A method of making a die adapted to form an extrusion comprising the steps of
Dependencies are inferred from the claim text.