Injection molding apparatus with alternately moved metal molds

In an injection molding machine of the type having two sets of metal molds each including a stationary metal mold half and a movable metal mold half, and mold clamping means for clamping together the stationary and movable metal mold halves for injecting molten material from an injection cylinder into a cavity formed by said stationary and movable metal mold halves, the improvement comprising:

• a metal mold supporting plate which supports said stationary metal mold halves and said movable mold halves of said two sets of metal molds at positions based in a direction perpendicular to an axis of said injection cylinder;
• means for reciprocating said metal mold supporting plate in a direction perpendicular to the axis of said injection cylinder for alternately setting said two sets of metal molds into said injection molding machine;
• said reciprocating means including an auxiliary support separate from a support for supporting said injection molding machine, a drive member mounted on said auxiliary support, a pinion driven by said drive member and journalled by said auxiliary support and arm means for transmitting movement of a shaft of said pinion to said supporting plate;
• means for moving one of said movable metal mold halves toward and away from one of said stationary metal mold halves which is held at a position at which said molten resin is injected into said mold cavity;
• and
• positioning means for positioning said metal mold supporting plate at a prescribed position, said positioning means being disposed below one of said stationary die plates which is set into said injection molding machine;
• and
• wherein said mold clamping means further secures said mold supporting plate and wherein each of said positioning means and said mold clamping means includes recesses formed in said mold clamping plate and a piston rod moves into and out of said recesses.