Differential pressure forming machine

Abstract

Abstract THIS DISCLOSURE RELATES TO DIFFERENTIAL PRESSURE FORMING MACHINES FOR MOLDING ARTICLES IN THERMOPLASTIC MATERIAL, AND MORE PARTICULARLY TO CERTAIN NOVEL AND USEFUL IMPROVEMENTS IN MACHINES OF THIS NATURE WHICH PERMIT SUDH MACHINES TO CYCLE MORE RAPIDLY AND THEREFORE PERMIT SUCH AN INCREASED QUANTITY OF PRODUCTS IN A GIVEN OPERATING TIME. THE INVENTION IS CONCERNED WITH A MACHINE OF THE TYPE WHICH CAN BE PLACED IN POSITION OFR IN-LINE OPERATION WITH AN EXTRUDER ISSUING A CONTINUOUS SHEET OF THERMOPLASTIC MATERIAL, OR WHICH MAY BE ADAPTED TO MOLD SHEETS OF THE THERMOPLASTIC MATERIAL WHICH ARE DRAWN FROM A ROLL. ACCORDINGLY, SUCH MACHINES USUALLY INCLUDE BANKS OF HEATERS, MOUNTED ABOVE AND BELOW THE LEVEL OF THE SHEET WHICH IS BROUGHT INTO THE MACHINE, TO BRING THE PALSTIC TO THE FORMING TEMPERATURE. FURTHER, FORMING MACHINES OF THIS CHARACTER USUALLY EMPLOY A PAIR OF PLATENS, ONE ABOVE AND ONE BELOW THE SHEET OR WEB OF MATERIAL, FOR MOUNTING MALE AND FEMALE DIE MEMBERS WHICH COOPERATE TO FORM PRODUCTS IN THE PREHEATED SHEET OF MATERIAL IN ACCORDANCE WITH THE CONFIGUARTION OF THE MOLDS. SUCH MACHINES MAY BE DEEP DRAW MACHINES SUCH AS ARE SUITABLE FOR FORMING CUPS AND THE LIKE OR SHALLOW DRAW MACHINES FOR FORMING ARTICLES SUCH AS CUP LIDS AND LIKE ARTICLES. GENERALLY SPEAKING, IN DEEP DRAW MACHINES OF THIS TYPE THE MALE DIES ARE PLUG ASSISTS WHICH AID IN MOVING PORTIONS OF THE PLASTIC SHEET INTO THE FEMALE CAVITIES, AND A VACUUM PUMP IS CONNECTED TO THE FEMALE CAVITIED, AND A VACUUM PUMP IS CONNECTED TO THE FEMALE CAVITIES TO DRAW THE MATERIAL INTO ENGAGEMENT WITH THE WALLS THEROF AT AN APPROPRIATE TIME. NESTING CHAINS ARE CONVENTIONALLY EMPLOYED TO CLAMP THE SIDES OF THE SHEET MATERIAL AND AT INTERVALS TO DRAW SUCCESSIVE LENGTHS OF IT FROM THE HEATING ZONE TO A POSITION BETWEEN THE FORMING DIES.

Inventors

• 👤 Gaylord W Brown
• 👤 Donald J Rise

Bibliographic Details