Abstract: Plasticizable material is pressure molded into articles free from flash in mold cavities of specialized molds defined by separate mold sections with removable cores. Prior to and during molding, the sections are held clamped together to fully confine the material which is pressurized by reducing the volumetric capacity of each cavity. This pressurization is maintained until the material is set or cured, and may be increased before final set to forge or densify the material further. The method employs a conventional press and two gangs of specialized two-piece, multi-cavity molds. The molds of each gang are supported in a horizontal row, with their juxtaposed flat faces and parting planes disposed vertically, for movement of each mold section flatwise endwise of the row to open and closed positions. The mold sections are clamped closed by power means which apply extraneous clamping pressure independently of the press operation.

Abstract: An improved heating system is disclosed including a heat-generating means and plenum, a conventional ducting system interconnecting the heat-generating means to one or more air discharge registers, particularly characterized in the utilization of a heat exchanger adjacent the heat-generating source and a heat exchanger adjacent the air discharge register, with said heat exchangers being interconnected by a heat-conducting tube carrying a quantity of thermally conductive liquid so as to utilize the improved conductivity of the liquid to minimize heat loss between the heat-generating source to the register. The invention discloses utilization of the heat-conducting tube either externally or internally of a conventional ducting system. Further, the tube is disclosed in a modification as being comprised of a plurality of segments interconnected by a slip-joint or sleeve which controls the transfer of heat between adjacent segments of the tubing.

Abstract: A quantity of discrete particles of thermo-meltable material are heated to melt those particles at the surface of the charge for a predetermined distance inwardly of the charge. The particles remote from the surface of the charge remain in original and unmelted condition. While the melted particles are in a melted condition molding pressure is applied to the exterior of the charge to shape the melted material into a covering encapsulating, at least in part, the unmelted particles. In a further embodiment the particles remote from the surface of the charge may under heat and pressure be superficially tacked together.

Abstract: Seamless hollow molding rubber articles are produced by concurrently molding two article halves with mateable edges which extend toward each other. Portions of the mold plates and core are maintained continuously at the full vulcanizing heat until the halves of the articles have been vulcanized to about 60 percent of the optimum vulcanization of the material, except for thin strata defining the mateable edges. By cooling at the portions which form these strata, these portions are maintained at a lesser temperature to cause the reaction in these strata to progress slightly beyond the scorching or blowing stage to dimensional and volumetric stability. At this stage, the mateable faces of the edges are substantially free from the usual "skin" effect which effect would render them non-fusible. The mold is then opened, the core is removed, and the mold is reclosed.