Vehicle wheel pneumatic tires and the manufacture thereof

In an injection molding apparatus for producing molded articles having a multipart core defining the inner side of a mold cavity, the core being reduced in size about its external periphery by relative displacement of individual parts for the removal of the article from the mold, a multi-part injection mold, said core inserted into said mold and completely enclosed thereby, said mold having upper, lower and sets of outer mold components, said sets of outer mold components being replaceable to form different sized mold cavities for the successive injection molding actions;

• the improvement comprising:
• a first injection molding station for injection molding a first part of said article, said first station disposed in a press, an upper thrust plate associated with said press, a first mold carrier having a first of said sets of outer mold components, a first closure bell for holding said core, said upper and lower mold components and first of said sets of outer mold components to define a first molding cavity, a first injection unit associated with said first molding station, a second injection molding station disposed in said press for molding a second part of said article, a second mold carrier arranged in a force transfer arrangement with said first closure bell, said second mold carrier having a second of said sets of outer mold components, a second closure bell for holding said core, said upper and lower mold components and second of said sets of outer mold components to define a second molding cavity, a base member in a force transfer relationship with said second closure bell, a second injection unit associated with said second molding station, force generating means to move said upper thrust plate toward said base and transmit a closure force through said upper thrust plate and said first and second closure bells to said base for simultaneous molding at said first and second stations, means for transporting said core, said upper and lower mold components with said first part to said second molding station for molding said second part, and means associated with said transporting means for placing and extracting said core, said upper and lower mold components relative to said first set of outer mold components when at said first injection molding station and relative to said second set of outer mold components when at said second injection molding station.