Plastic injection machine

Claim 1

IN A PLASTIC INJECTION MACHINE INCLUDING A BED AND A TABLE GUIDE ON SAID BED WITH A SHIFTABLE TABLE ON SAID GUIDE SUPPORTING A PAIR OF SPACED APART LOWER MOLD MEMBERS FOR RESPECTIVE MOVEMENT BETWEEN A CENTRAL INJECTING STATION AND OPPOSITE EJECTING STATIONS ADJACENT THE ENDS OF SAID TABLE GUIDE, THE IMPROVEMENT COMPRISING KNOCKOUT PIN SUPPORTING MEANS AT EACH OF SAID EJECTING STATIONS POSITIONED BENEATH SAID BED, UPWARDLY EXTENDING KNOCKOUT PINS FOR EACH OF SAID EJECTING STATIONS SUPPORTED AT THEIR LOWER ENDS DIRECTLY TO SAID PIN SUPPORTING MEANS, MEANS IN SAID GUIDE AND SAID BED AT EACH OF SAID EJECTING STATIONS DEFINING OPENINGS SUPPORTING A SUBSTANTIAL PORTION OF THE LENGTH OF SAID PINS FOR GUIDE RAISING AND LOWERING STRIPPING MOVEMENT THEREIN WITH THE UPPER ENDS OF SAID PINS RECEIVED AND SUPPORTED IN SAID TABLE GUIDE OPENINGS BENEATH SAID TABLE IN THE LOWERED POSITION THEREOF, MEANS IN SAID TABLE DEFINING OPENINGS BENEATH SAID LOWER MOLD MEMBERS PROVIDING FOR THE MOVEMENT OF THE UPPER ENDS OF SAID PINS THERETHROUGH, SAID PINS BEING PROPORTIONED TO EXTEND INTO OPERATIVE ENGAGEMENT WITH SAID LOWER MOLD MEMBERS THROUGH SAID TABLE OPENINGS IN THE RAISED POSITION THEREOF, A KNOCK-OUT PIN OPERATING MOTOR FOR EACH OF SAID STATIONS INCLUDING A HYDRAULIC PISTON MOTOR HAVING A FIXED CYLINDER AND A PISTON ROD CONNECTED TO SAID KNOCK-OUT PIN SUPPORTING MEANS TO EFFECT SAID GUIDED EJECTING MOVEMENT OF SAID PINS IN SAID BED AND TABLE GUIDE, A SOURCE OF HYDRAULIC FLUID UNDER PRESSURE, A SEPARATE ELECTRIC CONTROL VALVE FOR EACH OF SAID MOTORS, AND A COMMON CONTROL CIRCUIT FOR SAID VALVES INCLUDING A FIRST PAIR OF LIMIT SWITCHES FOR ACTUATION IN RESPONSE TO MOVEMENT OF SAID TABLE INTO SAID EJECTION STATIONS FOR THE RESPECTIVE SELECTION OF SAID CONTROL VALVES TO EFFECT THE EJECTION OF MOLDED ARTICLE FROM ONE OF SAID LOWER MOLD MEMBERS AT THE ASSOCIATED SAID STATION, A SECOND PAIR OF LIMIT SWITCHES, ONE FOR EACH OF SAID EJECTING STATIONS, HAVING CONTACT CONNECTED TO CONTROL THE ASSOCIATED SAID CONTROL VALVE AND POSITIONED TO BE OPERATED IN RESPONSE TO THE EJECTING MOVEMENT OF SAID PISTON ROD TO LIMIT THE EXTENT OF RAISING MOVEMENT THEREOF, AND A FUNCTION SELECTOR SWITCH IN SAID CIRCUIT HAVING A PAIR OF SELECTABLE POSITIONS WITH CONTACTS IN THE FIRST OF SAID SELECTABLE POSITIONS CONNECTED THROUGH SAID SECOND PAIR OF LIMIT SWITCHES TO PROVIDE FOR THE RAISING AND HOLDING OF SAID PINS IN A RAISED EJECTING POSITION AND HAVING FURTHER CONTACTS IN THE SECOND OF SAID SELECTABLE POSITIONS PROVIDING FOR THE RAISING FOLLOWED IMMEDIATELY BY THE LOWERING OF SAID KNOCK-OUT PINS.