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US 3,998,579 AGranted
Device for producing externally ribbed pipes of plastic
OwnerErik Gustav Wendel Nordstrominventor
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OwnerErik Gustav Wendel Nordstrominventor
Estimating the term…
A device for producing gilled pipes of plastic or other extrudable material, the device comprising two sets of mold jaw halves arranged on an endless line, one set running in a clockwise direction and the other set running in a counterclockwise direction, said mold jaw halves being brought to run close one to the other between a fixed groove shaped guiding rail and a parallel spring-biased guiding rail to define an entrance and an outlet, a nozzle is provided at the entrance and is capable of feeding material to be extruded thereto. A mandrel is positioned between the jaws concentric with the nozzle; the mandrel has an outer end shaped at least along a part of its length substantially as a truncated cone, the diameter of which increases in the direction away from the extrusion nozzle whereby to define with the mold jaws, a channel, the outer walls of the channel being formed by the mold jaws surrounding the mandrel and extending in the longitudinal direction of the mandrel, the inner sides of the mold jaws defining the outer shape of the pipe to be made and being provided with spaced substantially annular grooves. The angle between the generatrix and the longitudinal axis of the truncated cone is acute and less than 45.degree. so that the material by force will be pressed into the grooves by the conical portion of the mandrel head while jaws are passing the mandrel head so that the grooves of the mold jaws will be substantially filled at the same time as the pipe wall with an even inner wall in a longitudinal direction is being formed around the mandrel head.
A forming device for producing gilled pipes of extrudable material received from an extruder, said forming device comprising, a nozzle sleeve coupled to said extruder, a mandrel disposed in said nozzle sleeve and extending substantially therebeyond and defining therewith a tubular channel having an axially oriented orifice to enable passage of the extrudable material therepast, plural pairs of mould jaw halves arranged for transportation in an endless series, each mould jaw half having generally annular groove means formed in the inner wall surface thereof, guiding rail means coaxial with said nozzle sleeve and guiding said mould jaw halves so that they are brought together at the nozzle sleeve and at the mandrel, and that they separate after passing a distance coupled together to define a forming zone, said nozzle sleeve being coaxial with said mould jaw halves and being spaced inwardly from the inner walls thereof, and means forcing the extrudable material into a plurality of the grooves of said groove means within the forming zone substantially to fill same simultaneously with the formation of a smooth interior wall surface, said forcing means comprising an enlarged diameter head formed on the mandrel coaxial therewith and spaced from said orifice when said mandrel is within said forming zone, said head having a cylindrical, smooth surface external configuration for forming said interior wall surface and said mandrel having a conical portion integral and coaxial with said head and mandrel located adjacent said head, the generatrix of said conical portion forming an angle of less then 45.degree. with the axis of said conical portion and mandrel, the distance along said mandrel from said orifice to said head being about four to five times the mandrel diameter at said orifice.
Dependencies are inferred from the claim text.