Method and tool for producing a plastic container, particularly a fuel container, by internal pressure forming

Patent metadata

Field	Value
Publication number	US-2023191686-A1
Application number	US-201916982382-A
Country	US
Kind code	A1
Filing date	Mar 12, 2019
Priority date	Mar 19, 2018
Publication date	Jun 22, 2023
Grant date	—

Abstract

A method for producing a plastic container by internal pressure forming including arranging a hose-shaped preform between the molding dies of a mold, formed having a mold cavity; closing the mold and forming or preforming a container from the preform by internal pressure, wherein a circumferential section of the preform is pressed through a mold gap into a chamber surrounding the mold cavity and is pressed in the chamber against claw pairs having stationary inner retaining claws and movable outer tear-away claws; and laterally moving the outer tear-away claws, causing the circumferential section between the outer tear-away claws and the inner retaining claws to be torn open and the container to be split into two container halves. Also disclosed is a mold suitable for performing the method.

First claim

1 . A method for producing a plastic container by internal pressure forming, the method comprising:
disposing a tubular preform between mold parts of a molding tool configured to have a mold cavity; closing the molding tool and molding or premolding from the preform a container by internal pressure, wherein an encircling portion of the preform is pushed through a mold gap into a chamber that surrounds the mold cavity and in this chamber is pressed against claw pairs having stationary inner holding claws and movable outer tearing claws; and laterally displacing the outer tearing claws, on account of which the encircling portion is torn between the outer tearing claws and the inner holding claws, and the container is divided into two container halves.

2 . The method of claim 1 , wherein the molding tool between the inner holding claws and the outer tearing claws is cooled or heated by temperature-control elements.

3 . The method of claim 1 , further comprising:
opening the molding tool, wherein each container half remains in the corresponding mold part; fastening at least one built-in part to at least one of the container halves; closing the molding tool, wherein the container halves are joined, and blow-molding the joined container which herein is completely molded; and opening the molding tool and demolding the completed container.

4 . The method of claim 3 , wherein the mold parts when closing the molding tool for fully molding the container are converged more tightly than when closing for premolding the container.

5 . A molding tool for producing a plastic container by internal pressure forming a tubular preform, the molding tool comprising:
two mold parts configured to have a mold cavity and are movable relative to one another; at least one chamber which surrounds the mold cavity; and claw pairs which in the chamber are disposed about the mold cavity and which have stationary inner holding claws and movable outer tearing claws, wherein the tubular preform is disposed between the two mold parts, the molding tool is closed to perform molding or premolding from the preform to form a container by internal pressure, wherein an encircling portion of the preform is pushed through a mold gap into the chamber that surrounds the mold cavity and, in this chamber, is pressed against the claw pairs, and wherein the outer tearing claws are laterally displaced, and on account of which the encircling portion is torn between the outer tearing claws and the inner holding claws, and the container is divided into two container halves.

6 . The molding tool of claim 5 , wherein claw pairs having stationary inner holding claws and movable outer tearing claws are disposed on each of the two mold parts.

7 . The molding tool of claim 5 , wherein temperature-control elements are disposed between the inner tearing claws and the outer tearing claws.

8 . The molding tool of claim 5 , wherein the outer tearing claws are fastened to slides which simultaneously laterally delimit the chamber.

9 . The molding tool of claim 5 , wherein said molding tool has a first closing position and a second closing position.

10 . The molding tool of claim 8 , wherein the first closing position and the second closing position are enabled by dissimilar displacement paths of the slides.

Assignees

• Volkswagen Ag

Inventors

• Berlin Ralf
• Mientkewitz Claudia &

Classifications

• B29C49/4817 Primary

  with means for closing off parison ends · CPC title

• B29L2031/7172

  Fuel tanks, jerry cans · CPC title

• B29C2049/4825

  for cooling moulds or mould parts (B29C2049/5889 takes precedence) · CPC title

• B29C49/4823

  with incorporated heating or cooling means · CPC title

• B29C2049/4805

  by closing the mould halves · CPC title