Patent ID: 7296991

Claim:
An annular thermoplastic foam extrusion die assembly, comprising: an annular die having a first die body with a first die lip and a second die body with a second die lip, the second die body positioned adjacent the first die body with the second die lip configured relative to the first die lip to form an annular die gap therebetween, the first die body including a trench having an undercut, sloped back wall and the first die lip having a circumferential groove opposite the back wall; a plurality of die lip paddles spaced apart about the annular die gap, each having a tip and a heel, the tip configured to be received for pivotal movement in the groove and the heel configured to engage with the back wall as the heel is raised to drive the first die lip toward the second die lip to adjust a local portion of the annular die gap formed therebetween; a lifting mechanism configured to independently raise and lower each of the paddles; and a guide member configured to guide each of the die lip paddles for positioning in a radial direction as each of the paddles is independently pivotally positioned about the annular groove.