Tradesco Mold Limited

David Robert Brown

Henry John Rozema

Vincent Travaglini

Joseph Robert Klanfar

Nick Travaglini

A method and apparatus for distributing melt through three level stack molds. According to the method a crossover manifold is provided between adjacent mold levels of the stack mold, the crossover manifold having a plenum generally coaxial with a mold axis. Melt is introduced into the plenum through an inlet passage and distributed from the plenum to respective nozzle arrays through a separate outlet conduit associated with each mold level. The apparatus includes a crossover manifold mounted between first and second mold levels and having a plenum generally coaxial with the mold axis. An inlet conduit fluidly communicates with the plenum and an injection head to provide a melt path from the injection head into the plenum. A separate outlet conduit is provided for each mold level. Each outlet conduit fluidly communicates at one end with the plenum and at an opposite end with the injection nozzles of a respective mold level to provide a melt path from the plenum to each of the injection nozzles of the respective mold level. Each outlet conduit defines a respective melt path of generally equal length and resistance to melt flow.

Melt distribution arrangement for three level stack molds

A multi-level stacked mold having at least two and as many as four levels of cavities has a stock distribution mold block centred axially of the stacked mold blocks, the axially extending stock inlet passage to the distribution block connecting with radially off-set stock transfer passages that cross the axially openable mold block interfaces, into the adjoining mold blocks. These openable stock transfer passages, are each provided at their respective, non-encapsulated, radially off-set, opening interfaces with a valveless anti-drool arrangement. The mold flow passage system is subject to continual, extreme, thermal cycling and cyclical mechanical loading, during the repeated opening-and-closing cycles of the mold. Each separable anti-drool sealing interface has a relatively axially displaceable portion extending to bridge the initial gap opening between adjacent mold blocks and serving as an expansible piston means. This extension of the displaceable 'expansible piston means' portion is pressure responsive and serves to increase the internal volume of the adjacent transfer passage, while permitting equalizing the pressure of stock in the passage to atmospheric pressure, thus reducing the likelihood of the drooling of liquid plastic into the opening interspace, or the induction of atmospheric air into the flow passages.

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Terra Cotta, Canada

David Robert Brown