Molding machine

Claim 1

APPARATUS FOR FORMING MULTIPLE HOLLOW ARTICLES SUCH AS CONTAINERS AND THE LIKE FROM A SHEET OF THERMOPLASTIC MATERIAL; AND COMPRISING A MOLE DHAVING A PLURALITY OF LIKE CAVITIES, A LIKE PLURALITY OF ELONGATED PLUNGERS EACH OF A PERIPHERY AND LENGTH LESS THAN THE COOPERATION DIMENSIONS OF A ASSOCIATED MOLD CAVITY AND MOUNTED IN OPPOSITION TO THE MOLD FOR COOPERATION WITH A CORRESPONDING MOLD CAVITY FOR DRAWING PREDETERMINED AREAS OF THE SHEET INTO THE MOLD CAVITIES UPON RELATIVE MOVEMENT OF THE MOLD AND MOLD PLUNGERS TOWARD EACH OTHER, MEANS ENGAGING THE SHEET ADJACENT OPPOSITE MARGINS THEREOF FOR SUPPORTING THE SHEET IN TENSE CONDITION BETWEEN THE PLUNGERS AND THE MOLD AND CONSIDERABLY ABOVE THE MOLD, CLAMPING MEANS INCLUDNG MEANS DISPOSED IN INDEPENDENT SPACED POSITION ABOVE SAID MOLD AND INCLUDING A GRID BACK-UP MEANS LOCATED ABOVE THE SUPPORTED SHEET AND BELOW THE PLUNGERS AND HAVING A PLURALITY OF OPENINGS THERETO CORRESPONDING IN NUMBER TO AND RESPECTIVELY ALIGNED WITH THE MOLD CAVITIES WITH BACK-UP SURFACES AROUND EACH OPENING SPACED CONSIDERABLY ABOVE AND RADIALY OUTWARDLY OF THE MOUTHS OF THE MOLD CAVITIES FOR COOPERATIVELY SUPPORTING CORRESPONDING INTERNAL AREAS OF THE SHEET, SAID CLAMPING MEANS FURTHER INCLUDING SUPPORT MEANS BELOW SAID SHEET AND ABOVE SAID MOLD, SAID SUPPORT MEANS HAVING A PLURALITY OF APERTURES THEREIN RESPECTIVELY ALIGNED WITH AND OF SUBSTANTIALLY THE SAME SIZE AS SAID GRID BACK-UP MEANS OPENINGS, MEANS FOR SHIFTING SAID SUPPORT MEANS RELATIVE TO SAID GRID BACK-UP MEANS COOPERATIVELY TO CLAMP SAID SHEET THEREWITH FOR ACCURATELY DEFINING THE ENCLOSED PREDETERMINED AREAS TO BE STRETCHED INTO THE MOLD CAVITIES, MEANS FOR RELATIVELY SHIFTING THE PLUNGERS THROUGH THE OPENINGS IN SAID GRID BACK-UP MEANS OPENINGS AND SAID SUPPORT MEANS APERTURES AND FOR SHIFTING SAID MOLD TOWARD SAID SUPPORT MEANS AND SAID BACK-UP MEANS FOR SAID PLUNGERS TO ENGAGE ONLY A RELATIVELY SMALL CENTRAL PORTION OF EACH AREA AND THEREAFTER INTO CORRESPONDING MOLD CAVITIES TO DRAW THE CLAMPED AREAS OF THE SHEET AS PARTIALLY FORMED ARTICLES SUBSTANTIALLY INTO THE CORRESPONDING MOLD CAVITIES WITH OUT CONTACTING ADJACENT MOLD SURFACES, SAID MEANS FOR RELATIVELY SHIFTING THE PLUNGERS THEREAFTER FURTHER DRAWING THE PARTIALLY FORMED ARTICLES OF THE CLAMPED AREAS INTO THE MOLD CAVITIES, AND DIFFERENTIAL FLUID PRESSURE MEANS OPERATING WITHIN THE MOLED CAVITIES FOR EXPANDING THE DRAWN AREAS OF THE SHEET INTO ENGAGEMENT WITH THE INTERIOR SURFACES OF THE CORRESPONDING MOLD CAVITIES FOR COMPLETING THE FORMATION OF THE HOLLOW ARTICLES, EACH MOLD CAVITY HAVING AN UPSTANDING PORTION THEREABOUT MOVEABLE UP THROUGH THE CORRESPONDING SUPPORT MEANS APERTURE AND INTO THE CORRESPONDING BACK-UP MEANS OPENING AND COOPERATING WITH THE EDGE OF THE LATTER TO SHEAR THE RESPECTIVE PREDETERMINED AREAS FROM THE REMAINDER OF SAID SHEET.