Method of using a mold closing apparatus for an injection molding machine

A method of closing a mold with an apparatus comprising:

• a stationary mold platen fixedly connected by guide columns to a support,
• a mobile mold platen supported on said guide columns and further comprising support columns attached to said mobile mold platen, said support columns each having a stop rim located on at least one end;
• a lock plate defining passages configured to allow the sop rims of said support columns to pass through the passages;
• stop rim securing elements located on said lock plate so that when said mobile mold platen is displaced by displacement forces, said stop rims are displaced and are thereafter secured by said stop rim securing elements;
• at least one closing cylinder for displacing said mobile mold platen toward and against said stationary mold platen to close a mold in said mold platen and for displacing said mobile mold platen away from said stationary mold platen to open said mold, said closing cylinder at least comprising:
• an immobile piston cylinder attached to a second support,
• a displaceable double-acting differential piston at least partially within and guided by said immobile piston cylinder during displacement and acting against said lock plate,
• an immobile differential piston within said double-acting differential piston and attached to said second support;
• wherein said immobile differential piston divides interior space within said double-acting differential piston into a mold-opening cavity exhibiting mold-opening pressure surfaces and a first mold-closing chamber defined in part by interior surfaces of the double-acting differential piston and exhibiting mold-closing pressure surfaces, said pressure surfaces are configured so said mobile mold platen is displaced when pressure is applied to said pressure surfaces;
• and rapid-acting hydraulic cylinders acting on said mobile mold platen independently of said at least one closing cylinder;
• said method comprising the steps of:
• applying pressure rapidly to said mobile mold platen and rapidly moving said mobile mold platen toward said stationary mold platen;
• securing said stop rims on said support columns by said stop rim securing elements;
• applying pressure to said first mold-closing chamber pressure surfaces and to pressure surfaces of a second mold-closing chamber defined in part by an exterior portion of said double-acting differential piston of said at least one closing cylinder for displacing said mobile mold platen toward said stationary mold platen;
• maintaining said mobile mold platen against said stationary mold platen for a predetermined time period;
• and
• applying pressure to said mold-opening pressure surfaces of said at least one closing cylinder for displacing said mobile mold platen away from said stationary mold platen.