Injection molding of a thin-walled elongated tubular product such as a catheter

Claim 1

A molding assembly designed for high speed injection of melt for molding an elongated thin-walled tubular product, said molding assembly comprising: (a) a mold cavity including an interior surface configured to define the exterior surface of the tubular product and positioned to receive an in-flow of melt into an open end of the mold cavity, (b) a core pin disposed on the interior of said mold cavity and having an elongated, straight-line configuration and being disposed within said mold cavity in spaced relation to said interior surface of said mold cavity along a major portion of its length, (c) a support member having a central bore and being positioned between an upper and a lower platen, said central bore being structured to receive and support said mold cavity therein, (d) a tensioning means mounted exteriorly of said mold cavity adjacent an end thereof opposite to said open end and attachable to an exterior portion of said core pin for placing axially applied tension thereon, (e) distribution means disposed adjacent said open end of said mold cavity in receiving relation to the in-flow of the injected melt and structured for distributing the melt axially in surrounding relation to the core pin, (f) said distribution means further comprising a spider element mounted adjacent said open end of said mold cavity and supportingly engaging said core pin, so as to be movable therewith, said spider element disposed in receiving relation to the in-flow of melt, and comprising a plurality of apertures disposed in communicating relation with the interior of said mold cavity at said open end and collectively arranged for the direction of the flow of melt about said core pin into said mold cavity, (g) said distribution means further comprising a deflector pin mounted on said spider element and disposed in aligned, receiving relation to the in-flow of melt prior to entering said mold cavity, (h) vent means disposed and structured for the exiting of air from said mold cavity upon the filing of melt therein, said vent means being defined by a plurality of spaces formed between said core pin in the interior surface of the mold cavity, wherein the exterior portion of said core pin extends outwardly from the interior of the mold cavity and engages said interior surface thereof at a plurality of spaced apart points adjacent the location of exiting, (i) adjusting means for regulating in-flow imbalance characteristics of the plastic melt between said mold cavity and said core pin, said adjusting means disposed and structured to selectively adjust the relative transverse positions of the core pin and said interior surface of said mold cavity, whereby a preferred alignment between said mold cavity and said core pin can be established.