Heat sealing machines

Claim 1

IN A HEAT SEALER, THE COMBINATION OF LATERIALLY SPACED PAIRS OF CLAMPING JAWS FOR THE ENGAGING WORK TO BE SEALED, ONE PAIR OF SUCH CLAMPING JAWS INCLUDING A HEATED DIE FOR EFFECTING A SEAL, FOR SUPPORTING ONE JAW OF EACH PAIR OF OPPOSITE SIDES OF AN OPEN SPACE, A KNIFE DISPOSED BETWEEN SAID PAIRS OF CLAMPING JAWS AND HAVING MEANS GUIDING IT FOR MOVEMENT INTO AND FROM SAID OPEN SPACE BETWEEN THE PARIS OF CLAMPING JAWS AND TO AND FROM ENGAGEMENT WITH WORK EXTENDING ACROSS SAID SPACE AND ENGAGED BY THE RESPECTIVE PAIRS OF JAWS, AND MECHANISM FOR ACTUATING SAID CLAMPING JAWS AND KNIFE SEQUENTIALLY INTO WORK ENGAGEMENT, SAID MECHANISM BEING-ADAPTED TO ADVANCE THE KNIFE INTO SAID SPACE THROUGH AND BEYOND THE WORK ENGAGED BY THE JAWS, THE JAWS CLAMPING THE WORK WHILE THE KNIFE ACTS THEREON AND HOLDING THE WORK IN TENSION AS THE KNIFE ENTERS SAID SPACE, ONE OF THE JAWS MOUNTED ON SAID SUPPORTING MEANS HAVING A TAPERED SURFACE OVER WHICH THE WORK IS TENSIONED BY THE COMPLEMENTARY JAW ACTUATED BY SAID MECHANISM.