Apparatus improvements in a rotary blow molding machine

Claim 2

A rotary blow molding machine comprising a wheel having a plurality of arms, each arm carrying a partible mold which includes an inner and an outer mold section, said outer mold section being radially movable along said arm for closing said mold on a portion of a continuous tubular parison fed to said machine and for opening said mold to release an article formed therein, first cam means including a cam having an outwardly increasing mold-opening portion and a mold-closing portion and including followers carried with each outer mold section for periodic rolling engagement with said cam, second cam means for holding said mold sections closed during a portion of a rotary path of travel thereof, and spring means between the axis of said wheel and each inner mold section to permit one section of each partible mold to move incrementally substantially perpendicular to the axis of said wheel as said followers traverse segments of the mold-opening and mold-closing portions of said cam, whereby plastic is severed between an opening mold and a next adjacent still-closed mold because of outward differential movement of the inner mold section of the opening mold with respect to said next adjacent mold still held closed by the second cam means.

Claim 3

The machine of claim 1 wherein (a.) the mold-opening and mold-closing portions of said cam comprise rib sections having a width which varies in a direction substantially perpendicular to the axis of the rotary machine and (b.) each outer mold section includes two followers cooperating with said rib sections.

Claim 4

In a multi-station rotary blow molding machine which includes a number of partible blow molds arranged in angularly equispaced configuration about a main shaft, first cam means for moving one section of each partible mold toward and away from another section of each mold and second cam means for holding said mold sections closed during a portion of a rotary path of travel thereof, the improvement wherein said first cam means comprises a cam including mold-opening and mold-closing portions, each of said mold-opening and mold-closing portions having outer and inner surfaces, outer and inner followers associated with each outer mold section for cooperation with said mold-opening and mold-closing portions, said outer follower adapted to cammingly rotate in one direction along the outer surface of the mold-opening portion of said cam during movement of said one mold section away from the other mold section, and said inner follower adapted to continuously rotate in the opposite direction along the inner surface of the mold-closing portion of said cam during movement of said one mold section toward the other mold section, the distance between said roller followers defining a centerline, the angular position of said centerline changing with respect to a tangent to the mold-opening and mold-closing portions of said cam during movement of said one mold section toward and away from the other mold section, said tangent taken at a point on the intersection of said centerline and said surfaces of the mold-opening and mold-closing portions.

Claim 5

In a multi-station rotary blow molding machine which includes a number of partible blow molds arranged in angularly equispaced configuration about a main shaft, first cam means for moving one section of each partible mold toward and away from another section of each mold and second cam means for holding said mold sections closed during a portion of a rotary path of travel thereof, the improvement wherein said first cam means comprises a cam including mold-opening and mold-closing portions, each of said mold-opening and mold-closing portions having outer and inner surfaces, outer and inner followers associated with each outer mold section for cooperation with said mold-opening and mold-closing portions, said outer follower adapted to cammingly rotate in one direction along the outer surface of the mold-opening portion of said cam during movement of said one mold section away from the other mold section, and said inner follower adapted to continuously rotate in the opposite direction along the inner surface of the mold-closing portion of said cam during movement of said one mold section toward the other mold section, the distance between said roller followers defining a centerline, the angular position of said centerline changing with respect to a tangent to the mold-opening and mold-closing portions of said cam during movement of said one mold section toward and away from the other mold section, said tangent taken at a point on the intersection of said centerline and said surfaces of the mold-opening and mold-closing portions.

Claim 6

The machine of claim 3 wherein (a.) the mold-opening and mold-closing portions of said cam comprise rib sections each having a width which varies in a direction substantially perpendicular to the axis of the rotary machine and (b.) said centerline is fixed.