Mold clamping device and molding method

摘要

A movable platen ( 4 ) capable of advance and retraction with respect to a fixed plate is provided with a tie bar connecting device ( 12 ) for meshing a split nut ( 18 ) with the multiple groove portion ( 16 ) of a tie bar ( 10 ), and a mold clamping cylinder ( 20 ) operable with the split nut ( 18 ) serving as a reaction force point. The mold clamping cylinder ( 20 ) comprises a primary piston ( 22 ) contacting the split nut ( 18 ) and a secondary piston ( 24 ) movable relative to the primary piston ( 22 ). It is arranged that the movable platen ( 4 ) is stopped just before the position at which the movable mold contacts the fixed mold, and in this state the split nut ( 18 ) is reliably meshed with the multiple groove portion ( 16 ). Thereafter, the secondary piston ( 24 ) and primary piston ( 22 ) are moved integrally with respect to the movable platen ( 4 ) so as to effect mold contacting and mold clamping. After molding, the secondary piston ( 24 ) and the primary piston ( 22 ) are relatively moved to effect mold release.