Hermetic closure seal
AssigneeMedtronic, Inc.
InventorRobert E. Kraska
Life of this patent
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Abstract
A closed container is filled through a metal fill port which is then sealed with a rigid metal ball press fitted into the port passageway.
Claims5
A battery having a fill port with a hermetic seal, the hermetic seal comprising in combination a container having a cylindrical passageway defined by a wall made from a material selected from the group consisting of ¼ hard stainless steel and annealed stainless steel, a smooth, rigid ball of slightly larger diameter than that of the passageway, the smooth ball having a surface finish of less than about 5 micro inches, the ball having a hardness of greater than about 55Rc provided by a material selected from the group consisting of a transition metal carbide and an iron base alloy hardened by martensitic phase transformation, the ball being press fit into the passageway causing the passageway metal to flow about the ball forming a seal therewith.
A method for making a battery comprising the steps of:
- providing a stainless steel case;
- making a cylindrical passageway of uniform diameter in the case;
- annealing the stainless steel of the case at the passageway;
- providing a smooth, rigid metal carbide ball having a spherical shape and a uniform diameter greater than the diameter of the circular passageway and a surface having a hardness greater than about 55Rc, the smooth ball having a surface finish of less than about 5 micro inches;
- pressing the metal ball into the passageway causing the passageway metal to flow about the ball and form a seal therewith.
Dependencies are inferred from the claim text.