Abstract A method and apparatus for vacuum casting metal includes a furnace for forming a bath of molten metal in situ. A vertical sprue has its lower end immersed in the bath of molten metal in the furnace, with its upper end extending above the surface level of the bath and into a vacuum chamber. Within the vacuum chamber, a metal stripper plate having an aperture in fluid communication with the top of the sprue forms a fixed casting station. A plurality of vacuum casting molds are conveyed in seriatim into register with the casting station within the vacuum chamber, with an entry port in the bottom of each mold being brought into fluid communication with the aperture in the stripper plate. Each time a mold enters the vacuum chamber, the chamber is sealed and evacuated to draw molten metal up through the sprue and the stripper plate into the mold. Downward pressure is applied to the mold during the casting operation to prevent the leakage of molten metal from the path of fluid communication between the mold and the stripper plate. After the cast metal has solidified in the entry port of the mold and in the stripper plate, the solidified metal is broken between the mold and the stripper plate and any solidified metal remaining in the stripper plate and the sprue is ejected into the bath of molten metal at the lower end of the sprue. The vacuum chamber is then opened, the full mold is removed therefrom, and a new mold is transferred into the vacuum chamber.
Inventors
👤 Donald J Weiler
👤 John H Fritz
👤 B Frank Lewis
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-04 17:54
CPC Classifications
B; B22; B22D; B22D18/00; B22D18/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
230 words
A method of vacuum casting metal comprising the steps of: a. forming a bath of molten metal; b. immersing the lower end of a vertical sprue in said bath with the upper end of the sprue extending above the surface level of the bath; c. providing a metal stripper plate having an aperture extending therethrough in fluid communication with the top of said sprue; d. bringing a vacuum casting mold having an enlarged chill plate on the bottom thereof into fluid communication with said stripper plate; e. pressing said mold toward said stripper plate to prevent the leakage of molten metal from the path of fluid communication between said mold, chill plate and stripper plate; f. forming a vacuum chamber around said mold and withdrawing air therefrom to draw molten metal upwardly from said bath through said sprue, stripper plate and chill plate into said mold until said mold is filled; g. solidifying the metal in the path of fluid communication through said stripper plate, chill plate and mold; h. releasing the pressure of said mold and breaking the solidified metal between said chill plate and said stripper plate by vertically separating said mold and chill plate from said stripper plate; i. opening said vacuum chamber and removing said mold therefrom; j. and ejecting any solidifiEd metal remaining in said stripper plate and sprue into said bath of molten metal.
Claim 2
Independent Claim
230 words
A method of vacuum casting metal comprising the steps of: a. forming a bath of molten metal; b. immersing the lower end of a vertical sprue in said bath with the upper end of the sprue extending above the surface level of the bath; c. providing a metal stripper plate having an aperture extending therethrough in fluid communication with the top of said sprue; d. bringing a vacuum casting mold having an enlarged chill plate on the bottom thereof into fluid communication with said stripper plate; e. pressing said mold toward said stripper plate to prevent the leakage of molten metal from the path of fluid communication between said mold, chill plate and stripper plate; f. forming a vacuum chamber around said mold and withdrawing air therefrom to draw molten metal upwardly from said bath through said sprue, stripper plate and chill plate into said mold until said mold is filled; g. solidifying the metal in the path of fluid communication through said stripper plate, chill plate and mold; h. releasing the pressure of said mold and breaking the solidified metal between said chill plate and said stripper plate by vertically separating said mold and chill plate from said stripper plate; i. opening said vacuum chamber and removing said mold therefrom; j. and ejecting any solidifiEd metal remaining in said stripper plate and sprue into said bath of molten metal.
Claim 3
Dependent Claim
29 words
A method as set forth in claim 1 wherein the surface of said bath of molten metal is maintained in an atmosphere which is inert to said molten metal.
Claim 4
Dependent Claim
47 words
A method as set forth in claim 1 wherein steps (d) through (j) are cyclically repeated with a plurality of molds advanced in seriatim into register with said stripper plate, and said bath of molten metal is replenished as metal is withdrawn therefrom to fill said molds.
Claim 5
Dependent Claim
38 words
A method as set forth in claim 3 wherein said bath of molten metal is maintained in an atmosphere which is inert to said molten metal, and said bath is replenished with metal passed through said inert atmosphere.
Claim 6
Dependent Claim
47 words
A method as set forth in claim 1 wherein each of said molds and chill plates is carried on a carriage, and the vertical separation of said mold and chill plate from said stripper plate is effected by raising tracks for said carriage within said vacuum chamber.