Mold clamping apparatus

Abstract

An apparatus for moving upper and lower molds toward and apart from each other and giving additionally increased clamping force to the engaged molds. The apparatus includes a pair of reversible small power prime movers, a plurality of screw rod pairs, each of which consists of a first screw rod having an unthreaded extension and a hollow second screw rod embracing the unthreaded extension therein so as to freely rotate relative to the first screw rod, a pair of transmission mechanisms for transmitting rotary forces from the pair of prime movers respectively to the first screw rods and to the hollow second screw rods, a plurality of nut member pairs, each of which consists of a first nut member and a second nut member respectively threadedly engaged with the first and second screw rods so as to move up or down when the screw rods are rotated in one or other direction therealong, first and second molds respectively connected to the first and second nut members so as to move toward or apart with each other, and a piston device for giving additionally increased mold clamping force to the engaged two molds when the prime movers are stopped.

Dependencies are inferred from the claim text.