Abstract: A sprue bar nozzle assembly for controlling flow of melt through conduits of a mold assembly for injection molding comprises a sprue bar extension and nozzle, the sprue bar extension comprising means for adjusting the overall length of the sprue bar nozzle assembly and the nozzle comprising a nose comprising a seating surface for mating engagement with a mating surface of a mating segment of a melt conveying conduit and a slide valve, an open position of the slide valve permitting melt to flow through the sprue bar nozzle assembly and a closed position preventing melt from flowing through the sprue bar nozzle assembly, the slide valve being biased to a closed position by a biasing means and being driven to the open position by forces applied to the nose of the nozzle as a result of closure of an associated mold assembly.

Abstract: A nozzle controls flow of melt in injection molding equipment by passive actuation with opening and closing of a mold assembly. The nozzle comprises a valve pin having a pin passage therethrough movably supported within a nozzle passage and a contact arm transverse to and extending beyond the nozzle passage, the valve pin sealingly engaging the nozzle passage. Biasing means biases the valve pin to a closed position preventing passage of melt through the nozzle. The contact arm effects movement of the valve pin to an open position when closing of the mold assembly exerts a force on the contact arm to overcome the biasing means. A mold arrangement of plural mold assemblies comprises pairs of nozzles of the invention to control flow of melt through mating conduit segments between an injection unit and at least one mold assembly, the nozzles arranged and configured for seating engagement with abutment of the conduit segments.

Abstract: A pressure indicating fitting for injection molding equipment comprises a fitting body with a fitting bore therethrough, the fitting body being installed in the equipment with the fitting bore open to the interior of a passage for conveying melt, an indicating member received within the fitting bore and being bonded thereto to be retained in a normal position and being displaced therefrom to an indicating position by force from melt applied to the indicating member sufficient to cause the bond to fail, the indicating position determined by abutting contact of a surface of the indicating member with a surface of the fitting body and exposing a portion of a stem of the indicating member. Advantageously, the indicating member is retained in an indicating position by a press fit between the indicating member and fitting body. An injection molding manifold comprises a pressure indicating fitting in accordance with the invention.

Abstract: A latching device (20) for a mold assembly (10) uses a cam action to hold the “A” side plate against the hot runner system/nozzle plate (18) during operation. Preferably, a latch (20) is provided on each side of the mold to effectively hold the “A” side plate against the nozzle plate (18) during the high pressure injection of plastic melt. For purposes of a mold insert change, each latch (20) is rotated to release the “A” side plate from the nozzle plate (18), and hold the “A” side plate against the “B” side plate. This enables the “A” (12) and “B” (14) portions of the mold assembly to be moved away from the nozzle plate (18), thereby avoiding interference of the hot runner nozzles and “A” side insert and enabling quick mold insert change.

Abstract: A thermal expansion compensation support and method are used in a hot runner injection mold for maintaining liquid-tight relationships between parts that define a flow passageway. The support includes an annular housing having an annular recess that receives a spring, such as a Belleville washer, and a cover that overlies the annular recess in the housing. The housing and the cover are spring biased from each other to maintain a pressure force on the surfaces that are in contact with the outer faces of each of the cover and of the annular housing. The support imparts a holding force on the several parts of the machine that define the molding material flow passageway to prevent leakage. The method involves holding the parts together at a first holding force level for an initial portion of a warm-up temperature range and holding the parts together at a second holding force level for the remainder of the temperature range.

Abstract: A latching device (20) for a mold assembly (10) uses a cam action to hold the “A” side plate against the hot runner system/nozzle plate (18) during operation. Preferably, a latch (20) is provided on each side of the mold to effectively hold the “A” side plate against the nozzle plate (18) during the high pressure injection of plastic melt. For purposes of a mold insert change, each latch (20) is rotated to release the “A” side plate from the nozzle plate (18), and hold the “A” side plate against the “B” side plate. This enables the “A” (12) and “B” (14) portions of the mold assembly to be moved away from the nozzle plate (18), thereby avoiding interference of the hot runner nozzles and “A” side insert and enabling quick mold insert change.

Abstract: A molding nozzle controls the flow of material from a source of plastic melt to an outlet that communicates with a gate to a mold cavity. The nozzle contains a valve pin that includes a guide section and a valve end, and is movable toward and away from the gate to open and close the gate selectively. The valve pin is guided for movement by guide surfaces on inwardly-extending vanes within the nozzle, such that the guide surfaces engage the guide section of the valve pin. The valve end of the valve pin has a smaller diameter than that of the guide section, so that the valve section is free-floating to allow annular flow in the guide surface region to minimize the likelihood of formation of flow lines in the molded part.

Abstract: A thermal expansion compensation support and method are used in a hot runner injection mold for maintaining liquid-tight relationships between parts that define a flow passageway. The support includes an annular housing having an annular recess that receives a spring, such as a Belleville washer, and a cover that overlies the annular recess in the housing. The housing and the cover are spring biased from each other to maintain a pressure force on the surfaces that are in contact with the outer faces of each of the cover and of the annular housing. The support imparts a holding force on the several parts of the machine that define the molding material flow passageway to prevent leakage. The method involves holding the parts together at a first holding force level for an initial portion of a warm-up temperature range and holding the parts together at a second holding force level for the remainder of the temperature range.

Abstract: A thermal expansion compensation support and method are used in a hot runner injection mold for maintaining liquid-tight relationships between parts that define a flow passageway. The support includes an annular housing having an annular recess that receives a spring, such as a Belleville washer, and a cover that overlies the annular recess in the housing. The housing and the cover are spring biased from each other to maintain a pressure force on the surfaces that are in contact with the outer faces of each of the cover and of the annular housing. The support imparts a holding force on the several parts of the machine that define the molding material flow passageway to prevent leakage. The method involves holding the parts together at a first holding force level for an initial portion of a warm-up temperature range and holding the parts together at a second holding force level for the remainder of the temperature range.

Abstract: A valve for controlling the flow of fluent plastic material from an injection molding machine to a mold cavity. The valve includes an axially slidable valve pin that interacts with a material outlet to control flow through the valve selectively. The valve pin is actuated by an eccentric cam arrangement that positively drives the valve pin between positions where it is engaged with or disengaged from the material outlet. The cam acts on the valve pin only in an axial direction to avoid wear occasioned by side loads imposed on a valve pin.