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 probe with an elongated outer body has an electrical heating element wound in a helical coil around a central thermocouple tube integrally braze filled in silver in the body. A thermocouple bore extends through the tube into the silver adjacent the forward end of the body. This improves temperature control of the melt flowing around the probe and also facilitates manufacture.

Abstract: An injection molding nozzle having a melt channel with a number of diagonal portions which branch to equally spaced outlets for multi-cavity molding. The nozzle has an integral electrical heating element with a forward portion which extends adjacent the forward face of the nozzle between the spaced outlets of the melt channel. The forward portion of the heating element is integrally brazed in channels in the forward face of the nozzle and has a number of radially extending arms. One of the arms extends outward midway between each two adjacent outlets. This provides additional heat to the melt near the outlets and ensures it is evenly balanced between the diagonal portions of the melt channel.

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.