Plastic and nonmetallic article shaping or treating: processes – Direct application of fluid pressure differential to... – With internal application of fluid pressure
Patent
1979-09-11
1983-10-04
Pavelko, Thomas P.
Plastic and nonmetallic article shaping or treating: processes
Direct application of fluid pressure differential to...
With internal application of fluid pressure
264318, 264335, 264336, 425DIG218, B29D 2300
Patent
active
RE0314048
ABSTRACT:
Undercut tubular synthetic plastic articles, such as fittings, are formed in the mold cavity of an injection molding machine on a two-piece core a tubular component of which is surrounded by the undercut portion of the article and a first smaller-diameter portion at one side of the undercut portion. A cylindrical component of the core slidably guides the tubular component and is surrounded by a second smaller-diameter portion of the article at the other side of the undercut portion. When the injection of plasticized material is completed, the housing of the mold is opened to expose the undercut portion and the first smaller-diameter portion of the article on the core, the first smaller-diameter portion and the undercut portion are heated to or maintained at a temperature at which they can undergo elastic deformation, and the tubular component is moved axially of the article and of the cylindrical component so that the first smaller-diameter portion of the article is expanded by an external ring-shaped projection which forms part of the tubular component and was surrounded by the undercut portion. The first smaller-diameter portion of the article thereupon contracts so that its inner diameter is again less than the inner diameter of the undercut portion. The article is allowed to harden prior to complete separation from the core, and the first smaller-diameter portion is held against excessive contraction during hardening of the article.
REFERENCES:
patent: 3008181 (1961-11-01), Fitz
patent: 3064310 (1962-11-01), Cooprider
patent: 3183292 (1965-05-01), Dvoracek
patent: 3325576 (1967-06-01), Kessler
patent: 3402713 (1968-09-01), Senkowski
patent: 3749543 (1973-07-01), Stansbury
patent: 4005101 (1977-01-01), Ruch
patent: 4113829 (1978-09-01), Bowker
Osterreichische Schiffswerften Aktiengesellschaft Linz-Korneubur
Pavelko Thomas P.
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