Nozzle structure for injection molding machine

Claim 1

In combination in an injection molding machine, a tubular heating cylinder body including an inlet end and an exit end, an axial bore of constant diameter adjacent the exit end open at each end extending through said cylinder, said exit end having an abutment surface at the extremity of and surrounding said bore, a nozzle for said exit end comprising a generally tubular body extending within said heating cylinder and having: a. an axially extending bore open at each end; b. a probe portion having a distal extremity and a proximal end; c. a cylindrical plug portion of constant diameter joined with said probe portion at its proximal end, and including a flared opening diverging from said axially extending bore toward the outer surface of said cylindrical plug portion; and d. a radially extending abutment flange disposed adjacent the proximal end of said probe portion and having a diameter greater than said cylindrical plug portion for abutting engagement with said abutment surface; and means for securing the abutment flange in abutting engagement with said abutment surface, the axial length of said plug portion being from 50 to 100 percent of the diameter of said axial bore in said cylinder, and the clearance between said axial bore and said plug portion being no more than 0.003 inch, whereby an axially extending circumferential seal between the plug portion and the axial bore of said heating cylinder is formed.