Abstract: An apparatus for simultaneously pulling and twisting a cylindrical extrudate as a whole into a helical configuration, that is, a cylindrical configuration that, as a whole, has longitudinal and circumferential vector components. The apparatus is adapted to act on a solidified extrudate by causing it to be pulled downstream in the direction of its longitudinal axis while simultaneously being rotated about its axis. A circumferential twisting and a downstream pulling are simultaneously applied to a cooled and solidified extrudate. This is accomplished with a single piece of apparatus as shown. Thus, by twisting the solidified extrudate downstream both a circumferential and an axial component are imparted to the solidified extrudate. This, in turn, imparts a longitudinal and a circumferential movement to the molten extrudate as it emerges from an extruder die before it is fully solidified. The thus twisted molten extrudate is the cooled and solidified in its twisted condition.

Abstract: This specification describes an apparatus for carrying out a method of making a multi-walled pipe in the shape of a tube having a helical configuration. The apparatus is made up of an extruder with multiple dies. These multiple dies include at least two concentric arcuate dies that are radially spaced apart and a plurality of relatively straight dies that radially connect the concentric arcuate dies. The apparatus includes means for cooling the extrudate to solidify it into a usable condition. Means are provided to cause the multi-wall pipe to have a helical configuration, that is, apparatus is provided that arranges the pipe as a whole into a structure that has a circumferential component and a longitudinal component to its orientation; e.g. a helix. The longitudinal orientation is accomplished by providing apparatus that causes the pipe to proceed downstream in the direction of its longitudinal axis. In one embodiment of this invention, the extrudate is pulled longitudinally down stream.

Abstract: A method for providing an end-stop for a slider on a resealable thermoplastic bag is provided. The resealable thermoplastic bag includes a profile track having a first side panel and a second side panel. A clip having first and second legs is made to straddle the profile track such that the first leg of the clip being proximate to the first side panel and the second leg of the clip being proximate to the second side panel. One of the legs has an inward-facing protrusion for engaging a corresponding recess on the panel proximate thereto, such that the clip resists vertical motion on the profile track. The other of the legs of the clip is sealed to the panel proximate thereto.