Ejector-carrying straight-hydraulic mold clamping system

Claim 1

1 . In a direct mold clamping apparatus where a first ball nut is attached to a hollow pusher member, fixed to a movable platen, so as to be nonrotatable relative to said pusher member and movable integrally with said pusher member, and a first ball screw, which is threadedly engaged with the first ball nut and extends through a hollow portion of said pusher member, is rotated by means of a first drive source, thereby effecting mold closing or mold opening operation, a direct mold clamping apparatus with ejector, comprising: said first ball screw being axially formed with a hole at one end portion of the same screw remote from the movable platen; said pusher member being coupled to a central portion of an end face of said movable platen facing said pusher member through a substantially single ring-shaped junction plane; and an ejector, which includes: a second ball nut supported in said hollow, portion of said movable platen so as to be rotatable and axially immovable relative to said movable platen; a second ball screw mating with said second ball nut, disposed in axial alignment with said first ball screw, and having, at its one side remote from said movable platen, an end portion thereof removably fitted in said hole of said first ball screw; an ejector pin fixed to another end portion of said second ball screw facing said movable platen and arranged for projection from an end face of said movable platen remote from said pusher member; and a second drive source operatively connected to said second ball nut.