Method and apparatus for making helical plastic members, and the members produced
AssigneeNortene
InventorsMichel Pavy, Rene Casaert
Life of this patent
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Abstract
Helical plastic members are formed by rotating an extrusion die while extruding a filament in a generally horizontal direction just above a tank of liquid. The plastic helix so formed is cooled and solidified in the liquid. A mandrel in the liquid can be used to guide the helix downwardly, and the helix is removed from the tank with extraction rollers. As a variation, the tank can rotate relative to a fixed extrusion nozzle which extrudes the plastic horizontally just above the rotating liquid in the tank.
Claims10
A method of making a plastic material helical member comprising the steps of, continuously extruding into a liquid, hot plastic material generally horizontally from an extrusion orifice located near the surface of the liquid, while simultaneously rotating the extrusion orifice relative to the liquid about a generally vertical axis spaced from the extrusion orifice to form a helical plastic material shape about said axis, causing said helical shape to stabilize in the liquid, and removing the so formed helical member from the liquid.
Apparatus for forming a helical plastic member comprising an extruder having an extrusion orifice rotatable about a generally vertical axis spaced from the orifice while plastic material is extruded through the orifice;
- means to rotate said orifice;
- a tank containing liquid below the extrusion orifice;
- said extrusion orifice comprising means for extruding the plastic material generally horizontally about said axis and into said liquid while said orifice is rotating, to form a helical plastic shape, and means in said tank for extracting the helical shaped member.
Dependencies are inferred from the claim text.