Dry sand core process for use with lost foam molding process

Claim 1

A method of forming metallic castings, comprising: a. prepare a pattern from material which is combustible substantially without residue upon contact with molten metal, define said pattern with a remote internal cavity and a plurality of openings passing through the walls of said pattern to communicate with said cavity, b. close off all except one of said openings substantially with refractory material either in the rigid form or loose particulate form supported by a thin consumable membrane, c. locate said pattern in a molding apparatus, d. fill said pattern with dry unbonded sand through said opening either simultaneously with filling of said apparatus with dry unbonded sand or prior to the filling of said apparatus with dry unbonded sand, compact said sanD both within and about said pattern to achieve a density of at least 50-70%, and e. introduce molten metal to pattern to displace said material.

Claim 2

A method of forming metallic castings, comprising: a. prepare a pattern from material which is combustible substantially without residue upon contact with molten metal, define said pattern with a remote internal cavity and a plurality of openings passing through the walls of said pattern to communicate with said cavity, b. close off all except one of said openings substantially with refractory material either in the rigid form or loose particulate form supported by a thin consumable membrane, c. locate said pattern in a molding apparatus, d. fill said pattern with dry unbonded sand through said opening either simultaneously with filling of said apparatus with dry unbonded sand or prior to the filling of said apparatus with dry unbonded sand, compact said sanD both within and about said pattern to achieve a density of at least 50-70%, and e. introduce molten metal to pattern to displace said material.

Claim 3

A method of forming metallic castings, comprising: a. preparing a plurality of consumable pattern parts substantially combustible without residue upon contact with molten metal, said parts cooperatively defining at least one cavity within a single pattern when assembled together, male and female means being respectively located on said parts effective to promote a press lock therebetween when mated, b. assembling said parts together with said male and female means interlocked so as to define said predetermined pattern and cavity therein, and restricting all openings through said pattern except for one passage, c. filling said pattern with sand through said limited passage, compacting said sand to form a core within the pattern while insuring a full filling of all voids therein, d. adjusting the assembled pattern to return into its original predetermined configuration if distorted by filling, and e. locating said filled pattern within a molding flask, introducing said sand about the exterior of said pattern while arranging sprues and risers in appropriate alignment therewith, and finally subjecting said sprues and pattern to a molten charge to displace said pattern for defining a completed casting.

Claim 4

A method of forming metallic castings, comprising: a. preparing a plurality of consumable pattern parts substantially combustible without residue upon contact with molten metal, said parts cooperatively defining at least one cavity within a single pattern when assembled together, male and female means being respectively located on said parts effective to promote a press lock therebetween when mated, b. assembling said parts together with said male and female means interlocked so as to define said predetermined pattern and cavity therein, and restricting all openings through said pattern except for one passage, c. filling said pattern with sand through said limited passage, compacting said sand to form a core within the pattern while insuring a full filling of all voids therein, d. adjusting the assembled pattern to return into its original predetermined configuration if distorted by filling, and e. locating said filled pattern within a molding flask, introducing said sand about the exterior of said pattern while arranging sprues and risers in appropriate alignment therewith, and finally subjecting said sprues and pattern to a molten charge to displace said pattern for defining a completed casting.