Patent ID: 8113807
Filing Date: 2012-02-14
Classification: B29C,B29L,E04B,E04G

Abstract:
1. A thermoplastic extrusion unit for extruding a strip of thermoplastic material onto a preexisting strip of material, the preexisting strip having an upper surface and two opposed side surfaces, the upper and side surfaces defining a profile, the extrusion unit comprising: a source of pressurized heat-softened thermoplastic material; an extrusion head comprising a guide slot and an extrusion die, the guide slot having an edge adjacent the extrusion die, the extrusion die including a first opening having a guide portion and an extrusion portion, wherein: the guide portion of the first opening comprises a first open distal end and first and second opposed sidewalls extending from the edge down to the first open distal end, the extrusion portion of the first opening comprises a first proximal end wall and third and fourth opposed sidewalls extending from the first proximal end wall down to the edge, wherein the guide slot, the edge, and the guide portion of the opening are shaped and aligned to receive the profile of the preexisting strip; a drive mechanism including an engagement mechanism configured to engage the preexisting strip and to advance the extrusion head along the preexisting strip of material, wherein: the preexisting strip of material is received in the guide slot and the guide portion of the first opening as the extrusion head is advanced along the preexisting strip of material with the edge of the extrusion head resting on the upper surface of the preexisting strip of material, and the upper surface of the preexisting strip of material provides a first distal end wall for the extrusion portion of the first opening; and a feed mechanism to deliver the pressurized heat-softened thermoplastic material to the second portion, wherein the extrusion portion extrudes the strip of thermoplastic material as the extrusion head is advanced along the preexisting strip of material, wherein: the strip of thermoplastic material is fused to the upper surface on the preexisting strip of material.