Molding apparatus having a tunnel gated movable mold member

Claim 1

Apparatus for molding an article, which comprises: first die means having a first die cavity formed in a front surface thereof; second die means having a second die cavity formed in a front surface thereof; means movably mounting said second die means with the first and second die cavities positioned on opposite sides of a first parting line to define a portion of a molding cavity; a first mold member slidably mounted on the front of said second die means, said first mold member having a front die surface defining another portion of the molding cavity and located on one side of a second parting line which is perpendicular to the first parTing line; a second mold member slidably mounted on the front of said second die means, said second mold member having a front die surface positioned opposite to said first mold member die surface, to define another portion of the molding cavity; said second mold member having a front surface located on the opposite side of the second parting line and having a molding cavity wall extending substantially perpendicular to both of the parting lines, and said second mold member having a tunnel gate extending from the front surface of said second mold member substantially parallel to the first parting line, through said second mold member, and terminating at an acute angle with the perpendicular molding cavity wall in said second mold member to form a relatively sharp shearing edge; at least one of said first and second die means having a runner channel formed in the front surface thereof at the first parting line and extending to said tunnel gate when said second mold member is in a closed molding position; means for injecting molding material through said runner channel and said tunnel gate into the molding cavity; means for moving said second die means away from said first die means to pull the molded article from the first die cavity; means for positively retaining said first and second mold members against movement away from the article during an initial movement of said second die means away from said first die means; and means rendered effective after the initial movement of said second die means, for sliding said first and second mold members away from each other and away from the article being held fixed in the second die cavity; said movement of said second mold member moving the shearing edge thereon to sever the molded article from the molding material in the runnel gate.