Importance

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Abstract

Flowable molten plastic material is fed downwardly into an adjustable converging hopper mounted on a horizontal extruder barrel. This hopper is positioned around an opening feeding down into the barrel for guiding and deflecting a descending 'rope' of plastic material into engagement with screw flights of a rotating feed screw extending along the axis of the extruder barrel. The hopper comprises a box-like structure open at top and bottom and having two opposed side walls which slope inwardly downwardly toward each other for providing a downwardly converging configuration with a pair of vertical parallel end walls interconnecting the side walls. A larger of the two sloping side walls extends downwardly farther than the other and is inclined to vertical at a large angle than the shorter side wall. An adjustable extension of this larger sloping side wall comprises an adjustable converging deflector having a compound-angled surface 'X', and this deflector is adjustable downwardly and upwardly along the larger sloping side wall toward and away from the feed screw. Multiple deflection faces on surface X serve to follow approximately a spiral approach to the extruder screw for allowing and enabling molten plastic material to convey against surface X as the extruder screw is rotating into the material. Thus, the molten plastic material can slide over the rotating feed screw and create drag against adjustable surface X. The configuration of this surface provides an undercut for molten plastic material to become drawn into the screw flights and into the extruder.

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First Claim