Abstract: A method of making an integral heated nozzle using a terminal locating and sealing key. A spiral portion of an electrical heating element is press fitted into a spiral groove in the cylindrical outer surface of an elongated inner portion. The remaining outwardly extending terminal portions of the heating element are inserted through two holes in the key and the key is pushed inwardly to a position against the inner portion. The key has a pin portion which is received in a matching hole in the inner portion to exactly determine the length of the spiral portion of the heating element and accurately locates the terminal portion of the heating element. An outer collar portion having a slot in which the key is received is then mounted in place around the rear end of the inner portion. A thermosetting ceramic sealant is applied in the space between the inner and outer collar portions then heated to integrally joint them together.

Abstract: A valve member locating insert to be mounted in the front end of an injection molding nozzle. The locating insert has an outer mounting collar portion and a concentric inner collar portion which receives the reciprocating valve member to accurately locate it to prevent damage around the gate. The inner collar portion is connected to the outer collar portion by a single connecting vane portion. Melt flows through the locating insert in a C-shaped space between the collar portions. The vane portion and the inner collar portion have upstream and downstream ends which extend diagonally to be washed by the melt flow to avoid deadspots and reduce turbulence.

Abstract: An injection molding valve member having a smaller neck portion leading to a short head portion. This facilitates the backflow of melt around the head portion as the valve member is driven forwardly to the closed position. In one embodiment, the neck portion is formed by a number of flutes spaced around the valve member having lands between them.

Abstract: An injection molding torpedo which can itself be injection molded by a M/M process of a carbide alloy to have high resistance to corrosion and wear. The torpedo has a conical front surface which forms a pointed tip and a melt channel extending to an outlet on the conical front surface. The melt channel has a central rear portion extending from an inlet on the surface of the torpedo and a diagonal front portion extending from the rear portion to the outlet. The diagonal front portion of the melt channel is tapered inwardly enough to offset the diagonal at which it extends to allow for free ejection of the molded torpedo from its mold. This requires that the taper be enough that the shortest longitudinal line along the inner surface forming the melt channel does not diverge outwardly anywhere along its length.

Abstract: A method of making an elongated electrical heating element having a resistance wire with a helical portion extending between two lead pins surrounded by compacted insulating powder in an outer casing. The lead pins are attached to a tightly coiled resistance wire by screwing threaded portions at the inner ends of the lead pins into coiled portions at the outer ends of the resistance wire. The lead pins are pulled further apart to stretch the coiled resistance wire to form the helical portion of the resistance wire and then attached to a resistance meter. One of the lead pins is then rotated relative to the other lead pin to adjust the effective electrical resistance of the heating element to an accurate and uniform valve. The resistance wire and lead pins are mounted in an outer casing which further stretches the helical portion to a predetermined length. The outer casing is then filled with insulating powder in a conventional vibrating filling machine.

Abstract: Injection molding apparatus for side gating to several cavities spaced around a central heated nozzle extending through an opening in the mold. Several side gate seals are seated in a front portion of the nozzle, each in alignment between one of several radial portions of a melt channel through the nozzle and a gate leading to one of the cavities. The side gate seals each have an outer end which extends a sufficient distance outwardly past the inner surface of the opening in the mold to provide room for cooling conduits extending between the cavities and the central opening. The side gate seals are mounted after the nozzle is sealed in the opening in the mold. A gate insert is then mounted radially into position over the outer end of each side gate seal. A gate insert retainer plate secures the gate inserts in place.

Abstract: Injection molding apparatus for hot tip gating wherein a torpedo is screwed into a threaded seat in the forward end of a nozzle. The torpedo has an elongated shaft with a pointed tip mounted centrally in an outer collar by a pair of spiral blades which impart a swirling motion to the melt flowing to the gate. The temperature of the melt in the gate varies according to a continuous thermodynamic cycle in the torpedo. A thermocouple bore extends radially inward through the outer collar and one of the spiral blades to a conductive inner portion of the central shaft of the torpedo. The thermocouple bore is positioned whereby a thermocouple element extends radially outward from it into an insulative air space between the forward end of the nozzle and the mold. The thermocouple element has a substantially 90 degree rearward bend a predetermined distance from its inner end.

Abstract: Valve gated injection molding apparatus with a spring mounted on a central pin adjacent the head of a valve member in a spring chamber in each of the pistons. The spring is compressed between the base of the pin and the cap of the piston to preload it. When the valve member and piston are driven forwardly to the closed position, the head of the valve member retracts somewhat into the spring chamber against the force applied forwardly against the head of the valve member by the spring. This cushions the impact of the front end of the valve member in the gate and provides for tight seating of the front end of the valve member in the gate without requiring all of the components to be made to precise tolerances with exact allowance for thermal expansion. The spring is a number of selected disc springs stacked in sets facing in opposite directions, from which the force applied to the head of the valve member is predetermined.

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.

Abstract: A compact injection molding melt distribution manifold. The manifold has integral or monolithic inlet and main portions and both portions have a common electrical heating element. A melt passage extends through the manifold from a common inlet in the inlet portion and branches in the main portion to a number of spaced outlets leading to different gates.

Abstract: A pre-wired injection molding assembly to be supplied to the customer for installation in a mold. The assembly includes a number of sub-manifolds connected to a main manifold, a wiring frame having a number of elongated fingers connected to the sub-manifolds, and a number of heated nozzles connected to the sub-manifolds. The fingers of the wiring frame extend from a hollow channel member which leads to a connector box. The assembly is pre-wired by the supplier by running the wires from the nozzles along the fingers and through the channel member to the connector box. The pre-wired assembly is mounted from the rear in a matching mold manifold plate which greatly facilitates installation and disassembly for the customer.

Abstract: A sprue gated injected molding system having nozzles with a removable hollow gate insert received in a seat in the forward end of each nozzle to form the gate. Each gage insert has a forward portion with a tapered outer surface which abuts against a matching tapered surface of an opening through to mold to the cavity. The forward portion of the gate insert is resilient which ensures extremely good contact between them under bearing pressure due to thermal expansion of the nozzle. Thus optimum uniform heat transfer is provided between the gate insert and the cooled mold. The gate insert has a circumferential removal flange to facilitate it being pryed out of the seat if replacement is required. In an alternate embodiment an elongated torpedo is seated centrally in the melt bore of each nozzle. The torpedo has an outer retaining ring and a number of radially extending tapered fins which form melt flow channels between them.

Abstract: A multi-cavity valve gates injection molding system. The pneumatic actuating mechanism to reciprocate each elongated valve member includes a piston which reciprocates in a cylindrical opening through a cylinder plate. A sealing bushing which is mounted around each valve member has a flanged portion which bridges an insulative air gap between the manifold and the cylinder plate. Thus, the sealing bushing forms part of the piston cylinder as well as sealing against melt leakage around the reciprocating valve member. The piston has a circumferential outer band formed of a graphite alloy seated in a groove formed between a front portion and a removable rear plate portion.

Abstract: A thermocouple assembly and method of making it wherein a pair of wires formed of dissimilar metals extend through electrical insulating material in a thin flexible stainless steel sheath. A forward portion of the sheath containing the wires is snugly received in a nickel alloy casing which is then bent to form an opening to receive a screw therethrough to accurately secure the forward end of the thermocouple assembly in place. The casing is made strong enough to maintain the circular shape and bending the sheath and casing together securely retains the sheath in the casing.

Abstract: An injection molding heated manifold having a melt passage with a longitudinal portion to convey melt from a molding machine to a number of different nozzles. The steel manifold has a pair of cooling bores extending parallel to and equally spaced on opposite sides of the longitudinal portion of the melt channel. A cooling fluid, such as air, flows through the cooling bores to quickly cool the manifold after the system is shut down to minimize deterioration of the melt in the melt channel. The air flows helically around spiral vanes which are mounted in the cooling bores to avoid temperature stratification along the melt passage.

Abstract: An injection molding steel valve member in which a central cooling shaft is surrounded by a series of concentric insulation chambers. Cooling water is pumped through the cooling chamber to remove heat from the forward end of the valve member so the adjacent melt in the cavity will solidify more quickly. The insulation chambers reduce lateral heat loss to minimize the problem of solidification of melt around the outer cylindrical surface of the valve member.

Abstract: A number of heated injection molding nozzles are mounted along the side surface of a melt conveying manifold. In one embodiment of the invention, a connector collar having a tapered flange portion is bolted to the side surface of the manifold to provide each melt bore outlet. Each nozzle has a matching flange portion with a melt bore inlet extending laterally from a side surface. The nozzle is mounted on the manifold by securing the flange portions together by bolting a wedge clamp having two halves over the aligned flange portions. This accurately aligns the inlet with the outlet and allows the nozzle to be rotated to a particular angular position. In another embodiment, a melt conduit member is mounted between the manifold and each nozzle. The melt conduit member is clamped to the manifold after being rotated to a desired angular position about a first axis.

Abstract: An injection molding system having at least one insulation gate seal extending outwardly to bridge an insulative air space between a heated nozzle and the adjacent cooled cavity plate. Each seal has a central bore therethrough to convey pressurized melt from the nozzle to the aligned gate. The outer end of each seal has a circular groove extending between a central portion and a surrounding flange portion. The flange portion is substantially larger in diameter than the gate and extends outwardly past the face of the central portion into sealing contact around the gate against the surrounding surface of the cavity plate. The combination of the clearance provided between the face of the central portion and the surrounding surface of the cavity plate and the distance between the gate and the surrounding flange portion limits the temperature of the cavity plate immediately around the gate, while still providing the necessary seal.

Abstract: A valve gated injection molding system for making hollow plastic products. A fixed pin extends through an elongated hollow valve member which is reciprocated between a retracted open position and a forward closed position in which the forward end of the valve member is seated in the gate. The fixed pin has a hollow portion for the flow of pressurized gas to a porous portion at the forward end which is centrally located in the gate. In the open position, gas from the fixed pin flows into the hollow center of a stream of melt which flows into the cavity around the forward end of the fixed pin to form a melt bubble in the cavity.

Abstract: This invention relates to an injection molding system having two heated nozzles mounted in tandem. The rearward nozzle is considerably longer than the forward nozzle and has a melt bore which is considerably larger in diameter than the melt bore of the forward nozzle. The smaller forward nozzle has a backplate secured to its rear end with a thin flanged portion which extends outwardly and rearwardly into bearing contact against a rearward mold core to secure the forward nozzle in position in a well in a forward mold core. The rear face of the backplate has a seat extending around the melt bore to receive a cylindrical forward portion of a gate insert mounted on the forward end of the rearward nozzle. Thus thermal expansion of the larger rearward nozzle is taken up by the forward portion of the gate insert sliding in the seat.