Rotary blow molding machine
AssigneeGraham Engineering Corporation
InventorsPaul M. Oles, Frederick J. Shepps
Life of this patent
Estimating the term…
Abstract
A rotary blow molding machine includes a base, a turntable on the base rotatable about a vertical axis and a number of mold units spaced around the turntable. Each mold unit includes a pair of mold halves which close on and capture a growing vertical parison at an extrusion station and then fall away from the parison as the parison is severed. The captured parison is blow molded and cooled as the blow unit is rotated around the turntable. The finished article, commonly a bottle, is ejected from between the mold halves before the mold halves return to the extrusion station.
Claims30
A rotary blow molding machine comprising:
- (a) A base;
- (b) A turntable rotatably mounted on the base;
- (c) A plurality of mold units mounted on and spaced around the turntable, each mold unit including a pair of mold halves defining a blow mold cavity when closed, and mold clamp drive means for opening the closed mold halves to permit removal of a blow molded article at an ejection station and for closing the open mold halves at an extrusion station to capture a parison within the mold cavities;
- (d) A turntable drive for moving the turntable around the base in steps to index the mold halves between stations spaced around the machine, the stations including an extrusion station and an ejection station;
- (e) An extrusion die head mounted relative to the base above the extrusion station in a fixed circumferential location and operable to extrude a continuously growing resin parison down into the extrusion station;
- (f) Vertical positioning means at the extrusion station for holding each mold unit indexed to the extrusion station in an elevated position so that the open mold halves move to either side of a parison growing down from the extrusion die head prior to closing of the mold halves and capture of the parison, and for lowering the mold units and closed mold halves vertically down from the elevated position faster than the rate of downward parison growth;
- (g) Parison separation means at the extrusion station for severing the captured parison from a new parison growing from the extrusion die head;
- (h) Blow means for expanding the captured parison against the mold cavity;
- and
- (i) Mold unit rise means for raising each mold unit to the elevated position prior to return of the mold unit to the extrusion station;
- whereby a parison is captured between closed mold halves, separated from the new parison and blow molded against the cavity as each mold unit is rotated around the base.
A rotary blow molding machine comprising:
- (a) A base,
- (b) A turntable mounted on the base for rotation about a vertical axis, the turntable including a horizontal support plate,
- (c) A plurality of mold units mounted on and spaced around the support plate, each mold unit including a mounting plate above the support plate, a vertical slide connection joining the plates, whereby the mounting plate is vertically movable between elevated and lowered positions, a lift member joined to the mounting plate, a pair of mold halves defining a mold cavity when closed, a slide connection securing the mold halves to the upper surface of the mounting plate so that the mold halves may be moved between opened and closed positions, and mold clamp means for opening the closed mold halves to permit removal of a blow molded article at an ejection station and for closing the open mold halves at an extrusion station to capture a parison within the mold cavities;
- (d) A turntable drive for moving the turntable around the base in steps to index the mold units between stations spaced around the machine including an extrusion station and an ejection station;
- (e) An extrusion head die mounted relative to the base above the extrusion station in a fixed circumferential location and operable to extrude a continuously growing resin parison down into the extrusion station;
- (f) A lift cam on the base extending partially around the circumference of the machine beneath the mounting plate, the lift cam including an end at the extrusion station and a rise surface engagable with the lift member remote from the extrusion station for lifting the mold unit from the lowered position to the elevated position prior to movement to the extrusion station;
- (g) A support pad beneath the mounting plate at the extrusion station;
- (h) Support pad drive means for moving the pad vertically between an upper position adjacent the end of the lift cam for supporting mold unit at the extrusion station in the elevated position so that lowering of the support pad lowers the mold unit at the extrusion station vertically away from the extrusion head;
- (i) Parison separation means operable so that a parison captured between the mold halves at the extrusion station is separated from a new parison growing from the extrusion die head above the closed mold halves as a mold unit is vertically lowered;
- and
- (j) Blow means for expanding a captured parison against the mold cavity;
- whereby a parison is captured between the closed mold halves of each mold unit at the extrusion station, separated from the new parison and blow molded against the cavity as the mold units are rotated around the base.
A blow molding machine comprising:
- (a) A mold unit including a pair of mold halves defining a mold cavity when closed,
- (b) A drive for moving the mold unit horizontally to a number of stations including an extrusion station and an ejection station,
- (c) A fixed extrusion die head located above the extrusion station and operable to extrude a continuously growing resin parison vertically down into the extrusion station,
- (d) Mold clamp means for opening the mold halves to permit removal of a blow article at the ejection station and for closing the open mold halves at the extrusion station to capture a parison within the mold cavity,
- (e) Vertical positioning means for both (1) holding the mold unit in an elevated position when moved to the extrusion station so that the open mold halves move to either side of the parison growing down from the extrusion die head prior to closing of the mold halves and capture of the parison and (2) releasing the mold unit so that it gravity falls vertically down from the elevated position faster than the rate of parison growth,
- (f) Parison separation means operable so that the captured parison is separated from the new parison growing from the extrusion head above the mold halves,
- (g) Blow means for expanding the captured parison against the mold cavity, and
- (h) Mold unit rise means located away from the extrusion station for raising the mold unit to the elevated position prior to return of the mold unit to the extrusion station, whereby the parison is captured between the closed mold halves, separated from the new parison and then blow molded against the cavity as the mold unit is moved between the stations.
A mold unit for a blow molding machine comprising a plate, a pair of mold halves on one side of the plate, the mold halves defining a blow mold cavity when closed, a slide connection mounting the mold halves on the plate while allowing movement of the mold halves toward and away from each other, an actuator on the plate to one side of the mold halves, a pivot bar on the plate to the other side of the mold halves having a pivot connection at the level of the side connection and two ends, a first connection joining the actuator to an adjacent mold half at a first distance above the slide connection, a second connection located a second distance below the side connection joining the actuator to one end of the pivot bar, and a third connection joining the other end of the pivot bar to the other mold half at a third distance above the slide connection, all of said distances being approximately equal, whereby upon movement of the actuator toward the pivot bar the first connection moves said one mold half toward the other mold half, said second connection moves the lower end of the pivot bar outwardly to pivot the bar about the pivot connection and move the upper end of the pivot inwardly, and the third connection moves the other mold half toward said one mold half so that the mold halves are closed without subjecting the slide connection to substantial torsional loading.
Dependencies are inferred from the claim text.