Apparatus and method for vulcanizing pneumatic tire

A pneumatic tire vulcanizing apparatus comprising an upper mold and a lower mold which is separable from the upper mold, in which each of its upper and lower molds has a plurality of sectors separable from one another in a circumferential direction, the sectors being configured to be movable into a larger diameter and a smaller diameter by sliding up and down along a tapered guide surface inclining outward toward mating surfaces of the upper and lower molds, and the sectors being provided with coil springs for biasing the sectors so as to always force the sectors into the smaller diameter, respectively,

• the apparatus further comprising:
• push pins positioned within the lower mold and contacting back segments of each of the sectors of the lower mold for moving the sectors of the lower mold into the larger diameter and the smaller diameter by sliding the sectors of the lower mold up and down, respectively;
• push pins positioned within the upper mold and contacting back segments of each of the sectors of the upper mold for moving the sectors of the upper mold into the larger diameter and the smaller diameter by sliding the sectors of the upper mold down and up, respectively;
• and
• drive cylinders positioned outside of each of the upper and lower molds and comprising cylinder rods configured to penetrate the upper and lower molds and contact rear ends of each of said push pins for actuating the respective push pins,
• wherein each of the push pins is provided with a corresponding one of said drive cylinders and cylinder rods, and is arranged to be substantially coaxial therewith during operation of said mold,
• wherein a speed of movement of the individual sectors into the larger and smaller diameters is controlled by the respective push pins actuated by the drive cylinders and cylinder rods, and
• wherein each of the springs, push pins, drive cylinders, and cylinder rods is parallel to the respective corresponding tapered guide surface.