Apparatus for making multiduct conduit

Claim 2

Mold apparatus for fabricating multiduct conduit having smooth inside bores, said mold apparatus comprising: a mold structure, mandrel means extending longitudinaLly within said mold wall structure, said mold wall structure having a top bell section and a lower section, lower pressure platen means for applying pressure to the material within the mold at the lower section, an upper pressure applying assembly for applying pressure to said material at the top bell section, and said upper pressure applying assembly comprising means for selectively mechanically changing the force exerted on the material within the mold with the same pressure being applied.

Claim 3

The apparatus of claim 1 wherein said upper pressure assembly comprises a bell pressure platen and a cooperating bell pressure head.

Claim 4

The apparatus of claim 2 wherein said bell pressure platen comprises a peripheral frame, and flexible body means attached to said peripheral frame.

Claim 5

Mold apparatus for fabricating multiduct conduit having smooth inside bores, said mold apparatus comprising: a mold wall structure, mandrel means extending longitudinally within said mold wall structure, said mold wall structure having a top bell section and a lower section, lower pressure platen means for applying pressure to the material within the mold at the lower section, an upper pressure applying assembly for applying pressure to said material at the top bell section, said upper pressure assembly comprising a bell pressure platen and a cooperating bell pressure head, said bell pressure platen comprising a peripheral frame, flexible body means attached to said peripheral frame, said flexible body means comprising molded rubber, said molded rubber means having apertures therein conforming to the shape of said mandrel means, and said upper pressure applying assembly further comprising means for mechanically varying the force due to the pressure applied.

Claim 6

Mold apparatus for fabricating multiduct conduit having smooth inside bores, said mold apparatus comprising: a mold wall structure, mandrel means extending longitudinally within said mold wall structure, said mold wall structure having a top bell section and a lower section, lower pressure platen means for applying pressure to the material within the mold at the lower section, an upper pressure applying assembly for applying pressure to said material at the top bell section, said upper pressure assembly comprising a bell pressure platen and a cooperating bell pressure head, said bell pressure platen comprising a peripheral frame, flexible body means attached to said peripheral frame, said flexible body means comprising molded rubber, said molded rubber means having apertures therein conforming to the shape of said mandrel means, and said upper pressure applying assembly further comprising means for mechanically varying the force due to the pressure applied.

Claim 7

The apparatus of claim 4 wherein said peripheral frame comprises a horizontal section and a vertical section and means for extending said flexible body along the outside of said vertical section.

Claim 8

Mold apparatus for fabricating multiduct conduit having smooth inside bores, said mold comprising: a mold wall structure, mandrel means extending longitudinally within said mold wall structure, said mold wall structure having a top bell section and a lower section, lower pressure plate means for applying pressure to the material within the mold at the lower section, an upper pressure applying assembly for applying pressure to said material at the top bell section, said upper pressure assembly comprising a bell pressure platen and a cooperating bell pressure head, said bell pressure platen comprising a peripheral frame, flexible body means attached to said peripheral frame, said bell pressure head comprising a top plate, pressure piston means attached to said top plate for applying pressure thereto, a bottom plate movably attached to said top plate, resilient means for maintaining said top and bottom plates spaced-apart but enabling said space to vary under pressure, said bottom plate shaped to fit contiguously within said flexible body means for applying pressure thereto, and locking means for selectively maintaining a fixed minimum distance between said top and bottom plates even under pressure.

Claim 9

Mold apparatus for fabricating multiduct conduit having smooth inside bores, said mold comprising: a mold wall structure, mandrel means extending longitudinally within said mold wall structure, said mold wall structure having a top bell section and a lower section, lower pressure plate means for applying pressure to the material within the mold at the lower section, an upper pressure applying assembly for applying pressure to said material at the top bell section, said upper pressure assembly comprising a bell pressure platen and a cooperating bell pressure head, said bell pressure platen comprising a peripheral frame, flexible body means attached to said peripheral frame, said bell pressure head comprising a top plate, pressure piston means attached to said top plate for applying pressure thereto, a bottom plate movably attached to said top plate, resilient means for maintaining said top and bottom plates spaced-apart but enabling said space to vary under pressure, said bottom plate shaped to fit contiguously within said flexible body means for applying pressure thereto, and locking means for selectively maintaining a fixed minimum distance between said top and bottom plates even under pressure.

Claim 10

The apparatus of claim 6 wherein said locking means comprises at least one locking member normally situated between said top and bottom plates, means for causing said at least one locking member to be jammed between said top and bottom plates when pressure is applied to said top plate, and handle means attached to said at least one locking member to remove said at least one locking means from said jammed condition to thereby enable said flexible body means to force said bottom plate closer to said top plate than said fixed minimum distance.

Claim 11

The apparatus of claim 7 wherein said at least one locking member is an L-shaped member, aperture means in said top plate, said L-shaped member normally aligned with said aperture means, and wherein said handle means can be operated to move said L-shaped members out of alignment with said aperture means whereby the horizontal part of said L-shaped member jams between said top and bottom plates when pressure is applied through said piston thereby forcing said flexible body means to assume a substantially horizontal contour.

Claim 12

The apparatus of claim 8 wherein said lower surface of said bottom plate is slightly convex, and the flexible body means is forced to a slightly concave contour.

Claim 13

Mold apparatus for fabricating multiduct conduit having smooth inside bores, said mold apparatus comprising: a mold wall structure, mandrel means extending longitudinally within said mold wall structure, said mold wall structure having a top bell section and a lower section, lower pressure plate means for applying pressure to the material within the mold at the lower section, an upper pressure applying assembly for applying pressure to said material at the top bell section, said upper pressure applying section comprising means for mechanically varying the force due to the pressure applied, said lower pressure plate comprising a metallic disc-shaped plate having apertures therein to enable said mandrel to fit therethrough, rubber pad means fixedly attached within said disc-shaped plate, aperture in said rubber pads coaxial with said plate apertures, and said pad apertures designed to press fit around said mandrels.

Claim 14

Mold apparatus for fabricating multiduct conduit having smooth inside bores, said mold apparatus comprising: a mold wall structure, mandrel means extending longitudinally within said mold wall structure, said mold wall structure having a top bell section and a lower section, lower pressure plate means for applying pressure to the material within the mold at the lower section, an upper pressure applying assembly for applying pressure to said material at the top bell section, said upper pressure applying section comprising means for mechanically varying the force due to the pressure applied, said lower pressure plate comprising a metallic disc-shaped plate having apertures therein to enable said mandrel to fit therethrough, rubber pad means fixedly attached within said disc-shaped plate, aperture in said rubber pads coaxial with said plate apertures, and said pad apertures designed to press fit around said mandrels.

Claim 15

The apparatus of claim 10 wherein said pad apertures are designed to provide bevels at the openings of said ducts.