Method of hollow article casting

Abstract

An outer mold part is positionable over an inner mold part. Lever means are carried on opposite sides of the outer mold part and operable by a lifting force to exert a separating force between the outer and inner mold parts. Lever means are carried by the outer mold parts for locking the molded article to it. The outer mold part and the molded article are lifted upwardly together as an assembly and are removed entirely from the inner mold part. The assembly is then set down, the outer mold part is unlocked from the molded article, the outer mold part is then picked up and removed from the molded article, and then the bottom is poured in and is connected to the molded article.

What is claimed is: .[.1. A method of casting a septic tank comprising: 
     
        bottom to the side wall means..]. 2. A method .[.according to claim 1,.]. .Iadd.of casting a septic tank comprising: 1ocating an inner mold part having a top and side wall means at a pouring site;   inserting over said inner mold part an outer mold part having side wall means which when the two mold parts are assembled is spaced laterally outwardly from the side wall means of the inner mold part and also projects upwardly above the top of the inner mold part;   introducing a plastic or fluid substance of a type which sets into a solid into the space between the respective side wall means of the two mold parts and into the space above the top of the inner part which is bounded by the upwardly projecting portion of the side wall means of the outer mold part, so as to cast together integral tank top and side wall means;   forming at least one opening in the top of said tank;   allowing said substance to set up at least until the top and side walls of said tank are self-supporting;   applying a separating force between the inner and outer mold parts, and at the same time applying a lifting force on the outer mold part and the tank therein, as an assembly, so as to separate such assembly from the inner part;   1ifting said assembly upwardly completely free of said inner mold part;   setting said assembly down on a supporting surface;   1ifting upwardly on the outer mold part alone, to cause its separation from the tank;   1ifting said outer mold part upwardly and completely free of said tank and removing it from the site of said tank;   introducing an additional amount of said substance through said access opening and into said tank, and depositing such substance on said supporting surface, in the area between the tank side wall means, so as to form a bottom for said tank;   firmly connecting said bottom to the lower peripheral portion of said tank side wall means while forming said bottom;   1ifting the completed tank, including the bottom free of said supporting surface following sufficient hardening of the bottom and connection of the bottom to the side wall means; and .Iaddend.further comprising providing the inner mold part with a base for supporting the lower edge of the outer mold part, pivotally mounting lever arms on the side wall means of the outer mold part, with a first portion of each lever arm located on one side of the pivotal axis and a second portion thereof on the opposite side of such axis, and applying said separating force between the inner and outer mold parts by lifting upwardly on one of said portions of each .[.level.]. .Iadd.lever .Iaddend.arm so as to cause the opposite portion of the lever arm to swing downwardly into a force applying contact against   
     
     
        said base. 3. A method according to claim 2, further comprising using an overhead lifting device for exerting an upward force on said lever arms and for lifting the outer mold part and the tank therein upwardly through its connection with the lever arms. .[.4. A method according to claim 1, further comprising pivotally mounting at least one holding implement for the tank onto the outer mold part, for pivotal movement between a position of interference with removal of the tank from the outer mold part and a position of noninterference with removal of the tank from the outer mold part, initially locking said implement in its tank removal interfering position and maintaining it in said position during both casting of the tank and moving of the outer mold part and tank as an assembly, and then unlocking said implement and moving it into its position of noninterference with removal of the tank from the outer mold part at a time prior to separation of the outer mold part from the tank..]. .[.5. A method according to claim 4, comprising using an overhead lifting force for moving the implement from its interfering position into its noninterfering position, and continuing to apply the upwardly lifting force on the implement after it is in its position of noninterference for lifting the outer mold part upwardly alone through its connection with 
     
     
        said implement..]. 6. A method according to claim .[.1.]. .Iadd.10.Iaddend., comprising introducing steam into the inner part for the purpose of heating the plastic or fluid substance as it is setting. 
     
     
           A method .[.according to claim 1,.]. .Iadd.of casting a septic tank comprising: 1ocating an inner mold part having a top and side wall means at a pouring site;   inserting over said inner mold part an outer mold part having side wall means which when the two mold parts are assembled is spaced laterally outwardly from the side wall means of the inner mold part and also projects upwardly above the top of the inner mold part;   introducing a plastic or fluid substance of a type which sets into a solid into the space between the respective side wall means of the two mold parts and into the space above the top of the inner mold part which is bounded by the upwardly projecting portion of the side wall means of the outer mold part, so as to cast together integral tank top and side wall means;   forming at least one opening in the top of said tank;   allowing said substance to set up at least until the top and side walls of said tank are self-supporting;   applying a separating force between the inner and outer mold parts, and at the same time applying a lifting force on the outer mold part and the tank therein, as an assembly, so as to separate such assembly from the inner part;   1ifting said assembly upwardly completely free of said inner mold part;   setting said assembly down on a supporting surface; lifting upwardly on the outer mold part alone, to cause its separation from the tank;   1ifting said outer mold part upwardly and completely free of said tank and removing it from the site of said tank;   introducing an additional amount of said substance through said access opening and into said tank, and depositing such substance on said supporting surface, in the area between the tank side wall means, so as to form a bottom for said tank;   firmly connecting said bottom to the lower peripheral portion of said tank side wall means while forming said bottom;   1ifting the completed tank, including the bottom free of said supporting surface following sufficient hardening of the bottom and connection of the bottom to the side wall means; and .Iaddend.further comprising during casting of the tank top and side wall means forming a plurality of voids in the lower inner wall portions of said tank, at locations spaced about said tank, and during formation of the bottom for the tank introducing some of the substance used for the bottom into said voids, so as to key   
     
     
        the bottom to the lower wall portion of the tank. 8. A method according to claim 7, comprising forming the voids by projecting elements from within the inner mold part outwardly through openings in the side wall means of the inner mold part and into the wall space formed between the respective side wall means of the two mold parts, and withdrawing such elements into the interior of the inner mold part after casting of the tank top and side wall means and prior to exerting the upward force on the outer mold part for the purpose of lifting it and the tank as an assembly free from the 
     
     
        inner mold part. 9. A method according to claim .[.1.]. .Iadd.10, .Iaddend.further comprising employing an inner mold part which includes substantially opposed recesses in the side wall means thereof, which recesses extend downwardly from the top of said inner mold a substantial distance but less than the full height of said side wall means; inserting a filler body into each recess following assembly of said inner and outer mold parts, which filler bodies are each smaller in cross-sectional dimension than their respective recesses, so that a space exists all around said filler bodies, and are of a height to extend upwardly substantially above the top of the inner mold part so that their upper ends are above the level of the tank top; during formation of the top and sied wall means of said tank introducing some of the plastic or fluid substance into the spaces surrounding the filler bodies; and following setup of said substance removing said filler bodies. .Iadd.10. A method of upright casting of a full height septic tank, comprising: 1ocating an inner mold part having a top and upwardly tapering side wall means at a pouring site;   inserting over said inner mold part an outer mold part having upwardly tapering side wall means which when the two mold parts are assembled is spaced laterally outwardly from the side wall means of the inner mold part and also projects upwardly above the top of the inner mold part;   introducing a plastic or fluid substance of a type which sets into a solid into the space between the respective side wall means of the two mold parts and into the space above the top of the inner mold part which is bounded by the upwardly projecting portion of the side wall means of the outer mold part, so as to cast together integral tank top and side wall means;   forming at least one opening in the top of said tank;   establishing bottom keying components in the lower portions of the tank side walls while forming the tank top and side wall means;   allowing said substance to set up at least until the top and side walls of said tank are self-supporting;   applying a separating force between the inner and outer mold parts, and at the same time applying a lifting force on the outer mold part and the tank therein, as an assembly, so as to separate such assembly from the inner part;   1ifting said assembly upwardly completely free of said inner mold part;   setting said assembly down on a supporting surface in a curing site spaced from the pouring site;   1ifting upwardly on the outer mold part alone, to cause its separation from the tank;   1ifting said outer mold part upwardly and completely free of said tank and removing it from the site of said tank;   returning said outer mold part to the pouring site, for reinsertion over an inner mold part;   introducing an additional amount of said substance through said access opening and into said tank, and depositing such substance on said supporting surface, in the area between the tank side wall means, so as to form a bottom for said tank;   firmly connecting said bottom to the lower peripheral portion of said tank side wall means while forming said bottom, including using said keying components for mechanically keying the bottom to the tank side wall means;   1ifting the completed tank, including the bottom free of said supporting surface following sufficient hardening of the bottom and connection of the bottom to the side wall means..Iaddend. .Iadd.11. A method according to claim 10, further including casting into the tank side wall means a fillet inside the tank which extends between the tank top and the tank side wall   
     
     
        means..Iaddend. .Iadd.12.  A method according to claim 10, comprising applying the separating and lifting forces by means including a plurality of fluid motors..Iaddend. .Iadd.13. A method according to claim 10, further comprising introducing a heated fluid into the interior of the inner mold part for the purpose of providing heat for accelerating set of the plastic or fluid substance..Iaddend. .Iadd.14. A method according to claim 7, wherein the inner mold part includes upwardly tapering side wall means and the outer mold part includes upwardly tapering side wall means, resulting in a septic tank which tapers upwardly both on the inside and the outside..Iaddend. .Iadd.15. A method according to claim 14, further including casting into the tank side wall means a fillet inside the tank which extends between the tank top and the tank side wall means..Iaddend. .Iadd.16. A method according to claim 7, comprising applying the separating and lifting forces by means including a plurality of fluid motors..Iaddend. .Iadd.17. A method according to claim 14, comprising applying the separating and lifting forces by means including a plurality of fluid motors..Iaddend. .Iadd.18. A method according to claim 17, further comprising introducing a heated fluid to the interior of the inner mold part for the purpose of providing heat for accelerating set of the 
     
     
        plastic or fluid substance..Iaddend. .Iadd.19.  A method of upright casting of a full height septic tank, comprising: 1ocating an inner mold part having a top and upwardly tapering side wall means at a pouring site;   inserting over said inner mold part an outer mold part having upwardly tapering side wall means which when the two mold parts are assembled is spaced laterally outwardly from the side wall means of the inner mold part and also projects upwardly above the top of the inner mold part;   introducing a plastic or fluid substance of a type which sets into a solid into the space between the respective side wall means of the two mold parts and into the space above the top of the inner mold part which is bounded by the upwardly projecting portion of the side wall means of the outer mold part, so as to cast together integral tank top and side walls means;   forming at least one opening in the top of said tank;   allowing said substance to set up at least until the top and side walls of said tank are self-supporting;   applying a separating force between the inner and outer mold parts, and at the same time applying a lifting force on the outer mold part and the tank therein, as an assembly, so as to separate such assembly from the inner part;   1ifting said assembly upwardly completely free of said inner mold part;   setting said assembly down on a supporting surface in a curing site spaced from the pouring site;   1ifting upwardly on the outer mold part alone, to cause its separation from the tank;   1ifting said outer mold part upwardly and completely free of said tank and removing it from the site of said tank;   returning said outer mold part to the pouring site, for reinsertion over an inner mold part;   introducing an additional amount of said substance through said access opening and into said tank, and depositing such substance on said supporting surface, in the area between the tank side wall means, so as to form a bottom for said tank;   firmly connecting said bottom to the lower peripheral portion of said tank side wall means while forming said bottom, including mechanically keying the bottom to the tank side walls means;   1ifting the completed tank, including the bottom free of said supporting surface following sufficient hardening of the bottom and connection of the bottom to the side wall means..Iaddend. .Iadd.20. A method according to claim 19, further including casting into the tank side wall means a fillet inside the tank which extends between the tank top and the tank side wall   
     
     
        means..Iaddend. .Iadd.21.  A method of casting a septic tank comprising: 1ocating an inner mold part having a top and side wall means at a pouring site;   inserting over said inner mold part an outer mold part having side wall means which when the two mold parts are assembled is spaced laterally outwardly from the side wall means of the inner mold part and also projects upwardly above the top of the inner mold part;   introducing a plastic or fluid substance of a type which sets into a solid into the space between the respective side wall means of the two mold parts and into the space above the top of the inner mold part which is bounded by the upwardly projecting portion of the side wall means of the outer mold part, so as cast together integral tank top and side wall means;   forming at least one opening in the top of said tank;   allowing said substance to set up at least until the top and side walls of said tank are self-supporting;   applying a separating force between the inner and outer mold parts, and at the same time applying a lifting force on the outer mold part and the tank therein, as an assembly, so as to separate such assembly from the inner part;   1ifting said assembly upwardly completely free of said inner mold part;   setting said assembly down on a supporting surface;   1ifting upwardly on the outer mold part alone, to cause its separating from the tank;   1ifting said outer mold part upwardly and completely free of said tank and removing it from the site of said tank;   introducing an additional amount of said substance through said access opening and into said tank, and depositing such substance on said supporting surface, in the area between the tank side wall means, so as to form a bottom for said tank;   firmly connecting said bottom to the lower peripheral portion of said tank side wall means while forming said bottom;   1ifting the completed tank, including the bottom free of said supporting surface following sufficient hardening of the bottom and connection of the bottom to the side wall means;   pivotally mounting at least one holding implement for the tank onto the outer mold part, for pivotal movement between a position of interference with removal of the tank from the outer mold part and a position of noninterference with removal of the tank from the outermold part, initially locking said implement in its tank removal interfering position and maintaining it in said position during both casting of the tank and moving of the outer mold part and and tank as an assembly, and then unlocking said implement and moving it into its position of noninterference with removal of the tank from the outer mold part from the tank, and further comprising using an overhead lifting force for moving the implement from its interfering position into its noninterfering position, and continuing to apply the upwardly lifting force on the implement after it is in its position of noninterference for lifting the outer mold part upwardly alone through its connection with said implement..Iaddend.