Apparatus for heat sealing an open end of thermoplastic tubes

Claim 1

IN A HEAT SEALING APPARATUS OF THE THERMAL IMPULSE TYPE COMPRISING, IN COMBINATION, SEALING AND PRESSURE BARS POSITIONED OPPOSITE EACH OTHER AND MOUNTED FOR RELATIVE MOVEMENT TOWARDS AND AWAY FROM EACH OTHER; SAID SEALING BAR INCLUDING A SEALING BAND FACING THE PRESSURE BAR, ADAPTED TO BE HEATED BY PASSING A PULSE OF CURRENT THERETHROUGH, MEANS FOR RELATIVELY MOVING SAID BARS TO APPLY PRESSURE ON ONE END REGION OF A THERMOPLASTIC TUBE POSITIONED BETWEEN THEM WHEREBY SAID TUBE END IS CLOSED AND MADE TO ASSUME A FANTAIL FORM CONTACTING PLY PORTIONS, A SUBSTANTIALLY FLAT ELEMENT POSITIONED BETWEEN SAID BARS; SAID ELEMENT HAVING A NOTCH WHICH HAS OPPOSITE WALLS AND AN INTERMEDIATE FLOOR WALL; THE CONTACTING PLY PORTIONS OF SAID FANTAIL FORM BEING ADAPTED TO ENTER SAID NOTCH, FIT THEREIN AND CONTACT SAID FLOOR WALL; SAID SEALING BAND EXTENDING ALONG SAID CONTACTING PLY PORTIONS ACROSS THE TUBE WHEN SAID PLY PORTIONS ARE ENTERED IN SAID NOTCH; SAID BARS AND NOTCHED ELEMENT WHEN HOLDING SAID PLY PORTIONS, FORMING A MOLD CAVITY THEREFOR, AND SWITCHING MEANS OPERABLE IN TIMED RELATION WITH SAID BAR MOVING MEANS, FOR PASSING A PULSE OF CURRENT THROUGH SAID SEALING BAND WHEREBY SAID CONTACTING PLY PORTIONS WILL BE MADE TO CONFORM TO SAID MOLD CAVITY AND BE SEALED TOGETHER.