Hydraulic mold clamping mechanism for injection molding machine

摘要

A mold clamping mechanism for an injection molding machine characterized in that a relatively large mold clamping cylinder has a passage in its piston intercommunicating the head and rod ends of said mold clamping cylinder during stroking of said piston by a relatively small actuating cylinder for flow of oil from said head end into said rod end and into a makeup fluid tank having a capacity corresponding to the displacement of the piston rod of said mold clamping piston and vice versa during the respective mold opening and closing strokes. To effect mold clamping at required tonnage, the mold clamping cylinder has a port through which fluid under high pressure is admitted not only into the mold clamping piston to act on a fluid pressure actuated valve therein to close said passage, but also into the head end of the mold clamping cylinder to pressurize the fluid trapped therein by the closing of said passage.PPThe mold clamping mechanism herein is further characterized in that an indexable mold supporting platen carries a plurality of mold sections for successive indexing to register with a mold section carried by a movable mold supporting platen and adapted to be clamped by said mold clamping mechanism against a stationary platen.