Molding of elongate plastic cylinders

A method of molding in one piece an elongate cylindrical body including an end nozzle, having walls of generally uniform thickness including an end wall comprising said nozzle, and a cylindrical side wall, said end wall being joined substantially in transverse to an end of said cylindrical wall, comprising the steps of:

• inserting a male mold structure into a female mold structure having a cavity extending from an entrance to thereby form a clearance space between the female mold structure and the male mold structure, said clearance space providing a linear flow portion for forming said cylindrical side wall and a nonlinear portion for forming said end wall joined substantially in transverse to said cylindrical side wall;
• and
• injecting plastic into said linear flow portion in an area intermediate the ends of said linear flow portion and in close proximity to said nonlinear flow portion to supply plastic in one direction towards said nonlinear flow portion and in a generally opposite direction toward said female mold cavity entrance.

Apparatus for molding in one piece an elongate cylindrical hollow body having walls of substantially uniform thickness, requiring a linear and a nonlinear flow of plastic material to mold the cylindrical body, comprising a female mold structure providing a cavity that is shaped to define the exterior of said body, and extending inwardly from an entrance, a male mold member insertable into the cavity through said entrance and providing a clearance space of substantially uniform thickness between the male mold member and the female mold structure to define said body, said clearance space including a portion for said nonlinear plastic flow remote from said entrance, and a portion for said linear plastic flow, and means disposed intermediate the ends of said linear flow portion for injecting plastic material into said linear flow portion in an area adjacent said nonlinear flow portion of the clearance space to fill the clearance space, said injecting means supplying plastic into said clearance space in one direction towards the female mold cavity entrance and in a generally opposite direction to said nonlinear flow portion without causing substantial deflection of the male mold member.

Apparatus for molding in one piece an elongate cylindrical hollow body requiring a nonlinear flow of plastic material at one end of the cylindrical body, comprising female mold structure providing a cavity that is shaped to define the exterior of said body, the cavity extending inwardly from an entrance, a male mold member insertable into the entrance and providing a clearance space between the male mold member and the female mold structure to define said body, said clearance space including a portion for said nonlinear plastic flow remote from said entrance, and means for injecting plastic material into the cavity at a location along a cylindrical portion of said clearance space and adjacent and nonlinear flow portion of the clearance space such that, upon entering the clearance space, some of the plastic material flows in a first direction lengthwise of said cylindrical body towards said entrance and the remainder of the material flow in a different direction towards said nonlinear flow portion.