Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With means to heat or cool
Reexamination Certificate
1999-10-20
2001-12-04
Heitbrink, Tim (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With means to heat or cool
C264S328150
Reexamination Certificate
active
06325615
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to heater systems for injection molding equipment, particularly, the invention relates to such systems with heaters which require periodic replacement.
Plastic injection molding utilizes steel molds which are separable and have cavities into which molten plastic resin is injected. The pressures that the molds are subjected to can be extreme and thus the mold components are often massive to support such pressures. Often the nozzles which are utilized to inject the plastic resin into the mold cavities have ancillary heating to properly maintain the molten resin temperature. The ancillary heating is provided by heater coils or cartridges placed on or at the nozzles. In that these nozzles and ancillary heaters are positioned within the mold parts, channels, pipes, and tubing are provided thru the mold parts to provide electrical power to the heaters. The channel, tubing, and pipe sizes are kept to a minimum to reduce tooling costs and preserve the mold strength. The heaters conventionally utilize magnesium wire and operate at 240 volts. Such heaters periodically burn out.
The channels, pipe and tubing are typically electrically conductive so that the connection components must be insulated. The limited space, the high current requirements, and the necessity of maintaining the integrity of the electrical path, make conventional friction electrical connections, such as bullet and spade connectors unsuitable for these applications. Thus in the conventional system, connections between the heaters and conductor wires which run thru the mold parts are brazed or permanently crimped. When the heater burns out, the heater and the connecting wires has to be pulled through channels, pipe or tubing. New wires then need to be fished through the channels, pipe, or tubing. Alternately, the wires must be cut and rebrazed or new non-reusable crimp connectors installed. This is a time consuming process and can result in very expensive downtime for the injection molding equipment.
SUMMARY OF THE INVENTION
An injection molding system with an electric heater has a reusable high temperature electrical connection assembly that provides a very secure small diameter high current inline coupling.
The system is comprised of a mold, a heating, connecting wire and a connector assembly. The heaters and the mold are conventional and well known in the art. The connector assembly, in a preferred embodiment, has a male portion and a female portion. Each is permanently connectable to two wire ends to be removably connected. The male connector portion has a metallic tubular portion with a first end open for insertion and attachment by crimping or brazing of one wire end, and a second end having exterior threads for joining to the female portion. The second end also has a conductive pin integral with the metallic tubing and extending axially outward therefrom. The female portion has another metallic tubular portion with one end open for insertion and attachment by crimping or brazing of the other wire end to be connected, and an opposite end with an opening sized to receive the conductive pin and a flange. A nonconductive nut with internal threads is rotatably positioned on the second metallic tubular portion, adjacent the flange, for engagement with the exterior threads. High temperature resistant insulative tubing is disposed on the metallic tubular portions except for the flange and exterior threads such that the insulative nut is rotatable to secure the male and female connector portions together.
An object and advantage of the invention is that it allows wires to be quickly de-coupled and coupled in order to change the electric heater.
In injection molding applications, where the wires are run from the electrical component through channels, pipe or tubing to the power source, with this connection assembly, the wires can be left in place and only component needs to be removed and replaced. For example, a nozzle heater core.
A further object and advantage of the invention is that the threaded means of coupling eliminates accidental de-coupling, such as that which can occur with friction type connectors such as bullet and spade.
The small size allows it to be used in areas where space precludes the use of larger locking type plug connections.
These advantages also apply to similar components, particularly in the injection molding context, such as thermocouples.
REFERENCES:
patent: 4157806 (1979-06-01), Bourdon et al.
patent: 4557685 (1985-12-01), Gellert
patent: 4563795 (1986-01-01), Fournier
patent: 4771534 (1988-09-01), Gellert
patent: 5575941 (1996-11-01), Johnson
Branwall Eric Carl
Johnson J. Evan
Heitbrink Tim
Patterson, Thuente, Skaar & Christensen, P. P.A.
Thermetic Products, Inc.
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