Apparatus for molding plastic articles
US4496302A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 1982 |
| Grant date | Jan 29, 1985 |
| Priority date | — |
| Expiry date | Jun 4, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/058
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In order to mold tamperproof bottle closures or other plastic articles having a threaded cap frangibly connected with an adjoining skirt which has a number of internal projections or spurs inclined in a transverse plane at approximately identical acute angles to its inner peripheral surface, a male mold portion has a core in the form of a stepped cylinder with a small-diameter part rotatably enveloped by a sleeve flush with an adjoining large-diameter part jointly defining an annular gap with a surrounding shell. The sleeve has recesses in the shape of undercut slots forming the internal projections of a skirt molded in that gap; after sufficient hardening, the shell is rotated to extract these projections from their recesses with resulting radial expansion of the skirt into an adjoining space from which the shell has been axially withdrawn. A stripper then detaches the body of the molded article by an axial thrust from the large-diameter core part while axially entraining the shell which bears upon the expanded skirt to help eject the article from the mold; the skirt, still connected with the body by a rupturable link, thereafter elastically regains its original shape as do the sp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.