Molding of powdered or granular material

Claim 1

Apparatus for molding a shaped article from a moldable granular mix, comprising 1. an upper male die; 2. a lower female die, the area between the upper and lower dies defining a molding position; 3. a rubber sheet in the form of a conveyor belt, arranged to travel through the molding position, the rubber sheet being held in tension to avoid creasing of the rubber sheet when the dies are later brought together; 4. means for distributing the moldable granular mix on the rubber sheet, outside the molding position, in predetermined quantities and at spaced intervals; 5. a vacuum forming unit, provided under the rubber sheet opposite the mix distributing means, outside the molding position, said vacuum forming unit being provided with a. a shaped lower surface, said shaped lower surface corresponding to a desired nonuniform disposition of the mix on the rubber sheet; b. means for forming a vacuum in the vacuum forming unit to shape and hold the rubber sheet on the shaped surface, prior to distributing granular mix on the rubber sheet; and c. means for releasing the vacuum within the vacuum forming unit, after the distribution of granular mix thereon, allowing the rubber to assume it normal flat position; 6. means for moving the sheet, whereby a. to carry the mix in the desired nonuniform disposition into the molding position for molding, and b. to carry the molded article out of the molding position after molding; and 7. means for bringing the male die and female die together, whereby the mold the moldable granular mix into a shaped article having a predetermined nonuniform thickness.