Multi-cavity melt distribution manifold

• US 5,227,181 A
• Filed: 05/15/1992
• Issued: 07/13/1993
• Est. Priority Date: 12/19/1990
• Status: Expired due to Term

• Current Assignee: 4457528 Canada Incorporated
• Original Assignee: Mold-Masters Limited
• Inventors: Knudsen, Jerry A.
• Primary Examiner(s): HEITBRINK, TIMOTHY W
• Application Number:
  US07/884,601
• Time in Patent Office: 424 Days
• Field of Search: 425/549, 425/570, 425/571, 425/572, 425/588, 264/328.15, 264/328.8
• US Class Current: 425/549
• CPC Class Codes: B29C 45/2725 Manifolds
• CPC Class Codes: B29C 45/30 Flow control means disposed within the sprue channel, e.g. "torpedo" construction

Abstract

An injection molding manifold for distributing pressurized melt from a common inlet to thirty two outlets. The steel manifold has rear and forward plate portions which are integrally brazed together. The rear portion is drilled and plugged along a first transverse plane to provide the melt passage with branches from a common inlet portion to four intermediate portions. Four sets of matching grooves are machined in the joining faces of the rear and forward portions whereby each intermediate portion of the melt passage in turn branches along a second transverse plane to eight outlet portions, each leading to a cavity. The combination of the melt passage branching in several different directions in two different transverse planes with the second plane having different sets of curved portions allows the melt passage to have a large number of outlets while still having smoothly curved bends without having a leakage problem.

Claims

1. A unitary injection molding distribution manifold which branches at only two transverse planes to provide at least thirty-two outlets from a single common inlet, comprising:

(1) two brazed-together plates forming a unitary distribution manifold having a first plate with a rear face and a second plate with a forward face and first and second spaced-apart transverse planes which extend parallel to and lie between the rear and forward faces;

(2) a single melt passage extending generally longitudinally in the manifold from the rear face to the forward face and having;

(a) an unbranched, single, common inlet portion extending longitudinally from an inlet on the rear face to the first transverse plane where the melt passage branches in that transverse plane to at least four spaced-apart, unbranched first transverse plane passages;

(b) at least four spaced-apart, unbranched intermediate portions, each of which extends longitudinally from one respective first transverse plane passage to the second transverse plane where the melt passage branches in that second transverse plane to at least thirty-two second unbranched transverse plane passages;

(c) at least thirty-two spaced-apart, unbranched outlet portions, each of which extends longitudinally from one respective second transverse plane passage to a respective outlet on the forward face; and

wherein the melt passage extends an equal distance between the inlet and each outlet.

2. An injection molding manifold as claimed in claim 1 having a plurality of spaced bores, each bore extending through the manifold from the rear face to the forward face to receive an elongated heated probe therethrough, each bore having a rear portion and a forward portion, the rear portion of each bore extending from the rear face of the manifold to the second transverse plane and having a diameter to snugly receive the elongated probe therein, the forward portion of each bore providing one of the outlet portions of the melt passage extending from the second transverse plane to one of the outlets on the forward face of the manifold, the forward portion of each bore being larger in diameter than the rear portion of the bore and the heated probe extending through the bore, whereby the outlet portion of the melt passage extends along around the heated probe extending through the forward portion of the bore.

3. An injection molding manifold as claimed in claim 2 wherein at the second transverse plane the melt passage branches to at least eight curved portions of the melt passage, each of the curved portions extending in the second transverse plane to the forward portion of a respective one of the probe receiving bores, the curved portion of the melt passage being substantially smaller in diameter than the forward portion of the bore, the curved portion of the melt passage joining the forward portion of the bore being offset to one side of the heated probe extending through the bore to impart a swirling motion to melt flowing from the curved portion of the melt passage into the forward portion of the bore around the heated probe extending therethrough.