Patent ID: 6779999
Filing Date: 2004-08-24
Classification: B29C

Abstract:
A mold centering apparatus for controlling relative movement between mold plates in a stack mold, said stack mold having a first mold plate positioned between a pair of second mold plates, said first mold plate connected to said second mold plates by said centering apparatus, said mold plates being movable along a mold axis between an open position and a closed position, said first mold plate having mold faces on opposite sides of said first plate, said second plates being designed for mating with the faces on opposite sides of the first plate such that in said closed position molten plastic may be injected between said first and second plates, for producing molded plastic products, said centering apparatus comprising: an elongate threaded rod member comprising a central portion, and two oppositely extending, outer portions extending from said central portion parallel to said mold axis toward each said second plate, said central portion being attached to a peripheral portion of the first plate, said rod member being axially rotatable with respect to said first plate, said rod being prevented from axial movement relative to said first plate, each said outer portion including a threaded portion, the threaded portions of each said outer portion having the same thread count and pitch but being in opposite orientation to the other; a threaded connector secured to the periphery of each said second plate, each said connector defining a threaded bore therein, mating each respective threaded portion of the threaded rod, so that each second mold plate is connected with the first mold plate by said rod and connector to move between the open and closed positions along the mold axis upon rotation of the threaded rod; said portions of the rod rotating as one unit when secured together as the molding apparatus is moved between the open and closed positions, the outer rod portions rotating within each said bore an equal an opposite amount thereby equalizing the distances of each second mold plate from the first mold plate as the apparatus is moved between the open and closed positions; at least one rod outer portion being releasably detachable from said rod central portion, thereby allowing at least one said second mold plate to be separated from said first plate along the mold axis beyond said open position and beyond the length of the threaded rod without axial rotation of said rod and thus without said threaded connector losing threaded engagement with the at least one threaded rod portion.