Abstract: A method and an apparatus for injecting a steam into a mold in an injection molding machine by injecting a desired stream toward the opening of the metal mold including a gate and cavities in connection with the opening and closing operation of the metal mold thereby intending the cooling solidification of the molten resin on th gate portion and simultaneously intending removal of dewing and an oily matter on the surface of the metal mold.

Abstract: A runnerless method for injecting and molding a synthetic resin through a gate wherein a molten resin is intermittently cooled to solidification using a cooling medium to close the door for every injecting and molding operation of a molten resin in the gate, and relates also to a novel runnerless apparatus for injecting and molding a synthetic resin provided with a metal mold mechanism composed of a plural number of component members, in which the passage for the molten resin including a runner, the gate, and a cavity are drilled, a cooling medium-employing intermittent cooling mechanism for intermittently cooling the gate thereby enabling solidification of the molten resin in the gate, a mechanism for continuously applying heat to the gate for melting an existing resin, and an injection mechanism.

Abstract: A pointed heat-generating device includes a fine and small heat-generating coil which gradually changes its winding diameters or winding density. The pointed heat-generating device is fixed to a heat-generating front part of a projectile-shaped heat-generator main body. The thermal distance between the heat-generating coil in the pointed heat-generating device and the tapered peripheral surface of the heat-generating front part is shortened and maintained constant over its the whole area.