Method for molding a plastic washing machine basket

A method for manufacturing a one-piece plastic washing machine tub including a bottom wall and a cylindrical sidewall extending transversely from the bottom wall and including therein a plurality of holes, the holes being recessed from the interior surface of the cylindrical sidewall by depressions, said method employing a mold assembly including opposed first and second mold dies, a central mold core extending from the first mold die, the mold core including a plurality of teardrop-shaped projections each converging toward the narrowed end thereof in the same direction, and a plurality of side mold dies around the mold core, each of the side mold dies including a plurality of core pins, said method comprising the steps of:

• moving the first and second mold dies and the side mold dies to a mold closed position wherein each of the core pins engages the enlarged end portion of one of the teardrop-shaped projections on the mold core and wherein the first and second mold dies and the side mold dies define a mold cavity conforming to the dimensions of the tub,
• injecting plastic into the mold cavity to form the molded tub,
• displacing the second mold die to an open position relative to the first mold die,
• displacing the mold side dies outwardly to withdraw the core pins from the holes formed thereby in the molded tub, and
• displacing the molded tub from the mold core in a direction opposite the direction in which the teardrop-shaped projections converge.

An apparatus for molding a plastic washing machine basket having inner and outer sidewall surfaces with spaced apertures extending therethrough and teardrop-shaped grooves formed in the inner sidewall surface of the basket extending about the apertures, said apparatus comprising:

• a mold core having a first fixed end, a second end, and a plurality of teardrop-shaped projections spaced about an outer periphery thereof;
• a plurality of cavity sidewall members extending about the outer periphery of said mold core, each cavity sidewall member including a plurality of core pins having terminal ends which project toward said mold core from an inner surface of said cavity sidewall member, said cavity sidewall members being movable between open and closed mold positions such that when said cavity sidewall members are in a closed mold position, a first space is formed between the inner surfaces of the cavity sidewall members and the outer periphery of said mold core and the terminal ends of said core pins abut said teardrop-shaped projections, and when said cavity sidewall members are in an open mold position, the terminal ends of said core pins are spaced from the teardrop-shaped projections;
• a cavity cover member extending about the second end of said mold core with a second space therebetween and abutting said cavity sidewall members when said apparatus is in a closed mold position and being spaced from said cavity sidewall members when said apparatus is in an open mold position;
• and
• means for injecting a plastic material into said first and second spaces to form a plastic washing machine basket.

A mold assembly for use in the manufacture of an article, said mold apparatus comprising:

• a mold plate,
• a mold core projecting from said mold plate, said mold core including an outer surface portion adapted to form at least part of an interior surface of the article, said outer surface portion including a generally teardrop-shaped projection,
• a plurality of mold sidewall assemblies, each of said mold sidewall assemblies including an inwardly facing molding surface adapted to form a portion of an exterior surface of the article,
• means for supporting said mold sidewall assemblies for movement relative to said mold core and between a mold closed position wherein said inwardly facing molding surfaces and said mold core cooperate to define at least part of a mold cavity which conforms to the desired dimensions of the article, and a mold open position wherein each of said mold sidewall assemblies is displaced outwardly of its mold closed position, and
• a core pin supported on one of said mold sidewall assemblies, said core pin engaging said teardrop-shaped projection when said one mold sidewall assembly is in its mold closed position, and said core pin being adapted to form a hole in the article.

A mold assembly for use in the manufacture of an article having an annular interior surface, said mold apparatus comprising:

• a first mold plate,
• a second mold plate opposing said first mold plate,
• means for supporting said first and second mold plates for movement toward and away from each other between a mold open position and a mold closed position,
• a mold core projecting from said first mold plate in a direction parallel to the direction of movement of said first and second mold plates relative to one another, said mold core including a free end and an annular outer mold surface portion tapering inwardly in said direction and toward said free end and being adapted to form the annular interior surface of the article, said outer mold surface portion including a generally teardrop-shaped projection, said teardrop-shaped projection being adapted to form a teardrop-shaped depression in the annular interior surface of the article,
• a plurality of mold sidewall assemblies, each of said mold sidewall assemblies including an inwardly facing molding surface adapted to form a portion of the exterior surface of the article,
• means for supporting said mold sidewall assemblies for movement relative to said mold core and between a mold closed position wherein said inwardly facing molding surfaces and said mold core cooperate to define at least part of a mold cavity which conforms to the desired dimensions of the article, and a mold open position wherein each of said mold sidewall assemblies is displaced outwardly of its mold closed position, and
• a core pin supported on one of said mold sidewall assemblies, said core pin engaging said teardrop-shaped projection when said one mold sidewall assembly is in its mold closed position, and said core pin being adapted to form a hole in the article.

A mold assembly for use in an injection molding process to mold a one-piece article including a cylindrical sidewall extending transversely from a bottom wall, said mold assembly comprising:

• a first mold plate,
• a second mold plate opposing said first mold plate and including an inwardly facing molding surface adapted to form the exterior side of the bottom wall of the article,
• means for supporting said first and second mold plates for movement toward and away from each other between a mold open position and a mold closed position,
• a mold core projecting from said first mold plate in a direction parallel to the direction of movement of said first and second mold plates relative to one another, said mold core including a free end and an annular outer mold surface portion tapering inwardly in said direction and toward said free end and being adapted to form the interior surface of the cylindrical sidewall of the article, said annular outer mold surface portion including a plurality of generally teardrop-shaped projections, each of said teardrop-shaped projections being adapted to form a teardrop-shaped depression in the interior surface of the cylindrical sidewall of the article, each of said teardrop-shaped projections including a narrowed end portion and an enlarged end portion converging toward said narrowed end portion thereof in said direction and toward said first mold plate,
• a plurality of mold sidewall assemblies, each of said mold sidewall assemblies including an inwardly facing molding surface adapted to form a portion of the exterior surface of the cylindrical sidewall of the article,
• means for supporting said mold sidewall assemblies for movement between a mold closed position wherein said inwardly facing molding surfaces of said mold sidewall assemblies, said inwardly facing molding surface of said second mold plate, and said mold core cooperate to define at least part of a mold cavity which conforms to the desired dimensions of the article, and a mold open position wherein each of said mold sidewall assemblies is displaced outwardly of its mold closed position, and
• a plurality of core pins, each of said core pins being mounted on one of said mold sidewall assemblies and projecting from said inwardly facing molding surface thereof, each of said core pins engaging the enlarged end portion of one of said teardrop-shaped projections of said mold core when said mold sidewall assemblies are in their mold closed positions, and each of said core pins being adapted to form a hole in the cylindrical sidewall of the article, the hole being recessed in one of the teardrop-shaped depressions from the surrounding portion of the annular interior surface of the article.