Method for making electrical heating mats and blanks therefor

Claim 1

A METHOD FOR MAKING LOW TEMPERATURE ELECTRICAL HEATING ELEMENTS HAVING AT LEAST ONE RESISTOR IN THE FORM OF A RESISTANCE FOIL OF UNIFORM THICKNESS EXTENDING IN SINUOUS WINDINGS OF UNIFORM WIDTH, SAID METHOD COMPRISING: (A) ADVANCING AT LEAST ONE THIN RESISTANCE FOIL WEB OF A SUBSTANTIAL WIDTH, (B) WHILE REMOVING UNIFORM WIDTHS OF FOIL MATERIAL FROM SAID RESISTANCE WEB TO FORM A FIRST SET OF NUMEROUS NARROW LONGITUDINAL SLOTS AND A SECOND SET OF CORRESPONDING SLOTS ARRANGED RESPECTIVELY BETWEEN THE SLOTS OF SAID FIRST SET, THE SLOTS IN EACH SET BEING INTERRUPTED OVER UNIFORMLY SPACED-APART AREAS LOCATED APPROXIMATELY MID-WAY BETWEEN THE INTERRUPTIONS OF THE OTHER SET, (C) THEN, WHILE THE THUS-SLOTTED FOIL WEB IS BEING FURTHER ADVANCED, APPLYING TO EACH SURFACE THEREOF A CONTINUOUS WEB OF FLEXIBLE INSULATING MATERIAL, THE WIDTH OF SAID INSULATING WEBS BEING AT LEAST SUFFICIENT TO COVER SAID FOIL WEB OVER ITS WIDTH (D) AND ADHERING THE INSULATING WEBS TO EACH OTHER SO THAT A COILABLE COMPOSITE WEB RESULTS WHICH CAN SUBSEQUENTLY BE SEVERED ACROSS THE AREAS OF INTERRUPTIONS OF SAID SLOTS, TO PRODUCE SEPARATE, THIN, FLEXIBLE INSULATED HEATING MATS.

Claim 2

A METHOD FOR MAKING LOW TEMPERATURE ELECTRICAL HEATING ELEMENTS HAVING AT LEAST ONE RESISTOR IN THE FORM OF A RESISTANCE FOIL OF UNIFORM THICKNESS EXTENDING IN SINUOUS WINDINGS OF UNIFORM WIDTH, SAID METHOD COMPRISING: (A) ADVANCING AT LEAST ONE THIN RESISTANCE FOIL WEB OF A SUBSTANTIAL WIDTH, (B) WHILE REMOVING UNIFORM WIDTHS OF FOIL MATERIAL FROM SAID RESISTANCE WEB TO FORM A FIRST SET OF NUMEROUS NARROW LONGITUDINAL SLOTS AND A SECOND SET OF CORRESPONDING SLOTS ARRANGED RESPECTIVELY BETWEEN THE SLOTS OF SAID FIRST SET, THE SLOTS IN EACH SET BEING INTERRUPTED OVER UNIFORMLY SPACED-APART AREAS LOCATED APPROXIMATELY MID-WAY BETWEEN THE INTERRUPTIONS OF THE OTHER SET, (C) THEN, WHILE THE THUS-SLOTTED FOIL WEB IS BEING FURTHER ADVANCED, APPLYING TO EACH SURFACE THEREOF A CONTINUOUS WEB OF FLEXIBLE INSULATING MATERIAL, THE WIDTH OF SAID INSULATING WEBS BEING AT LEAST SUFFICIENT TO COVER SAID FOIL WEB OVER ITS WIDTH (D) AND ADHERING THE INSULATING WEBS TO EACH OTHER SO THAT A COILABLE COMPOSITE WEB RESULTS WHICH CAN SUBSEQUENTLY BE SEVERED ACROSS THE AREAS OF INTERRUPTIONS OF SAID SLOTS, TO PRODUCE SEPARATE, THIN, FLEXIBLE INSULATED HEATING MATS.