Thermal limiter for one or more electrical circuits and method of making the same

Abstract

This invention relates to a thermal limiter which can be used to limit one or more electrical circuits, such as multiple circuits in which one of the circuits is a primary circuit and the other circuits are secondary circuits energized or controlled by the primary circuit. The limiter of this invention is a unitary construction which can be connected to the primary and secondary circuits to control the same. A new method of making the limiter is included in this invention. This invention can be used in combination with a transformer for a television set in combination with its primary and secondary circuits, in combination with an air conditioning system, such as for automobiles, or in combination with other devices, as desired.

What is claimed is:  .[.1. A thermal limiter for at least one electrical circuit comprising a thermally responsive fuse, lead means operatively interconnected to said fuse for coupling said fuse in said circuit, an electrical circuit heater means disposed in a selected position relative to said fuse, and an insulating coating mass covering and securing said heater means and said fuse in said selected positioning thereof with said lead means having at least portions thereof exposed from said mass whereby said mass and said selected positioning provides a controlled time delay in said heater means being adapted to cause said fuse to blow and thereby open said one electrical circuit..]. .[.2. A thermal limiter as set forth in claim 1 wherein said heater means comprises a plurality of separate heater wires..]. .[.3. A thermal limiter as set forth in claim 1 wherein said heater means is spaced from said fuse, said mass being disposed between said heater means and said fuse and acting as a heat conductor therebetween..]. .[.4. A thermal limiter as set forth in claim 1 wherein said heater means comprises a heater wire coiled on said fuse..]. .[.5. A thermal limiter as set forth in claim 1 wherein said heater means comprises a heater wire disposed in series between one of said lead means and said fuse..]. .[.6. A thermal limiter as set forth in claim 1 wherein a housing means receives said heater means and said fuse therein in said selected positioning therebetween, said mass being disposed in said housing to cooperate with said housing to cover and secure said heater means and said fuse in said selected positioning thereof..]. .[.7. A thermal limiter as set forth in claim 6 wherein said heater means comprises a coiled heater wire having its opposed ends electrically interconnected to two lead means respectively having portions thereof exposed from said mass and from said housing means, said fuse having opposed sides thereof respectively electrically interconnected to said first mentioned lead means one of which is also one of said lead means electrically interconnected to said heater wire..]. .[.8. A thermal limiter as set forth in claim 1 wherein said lead means comprise a first pair of lead means respectively and electrically interconnected to opposed sides of said fuse, a second pair of lead means being respectively and electrically interconnected to opposed sides of said heater means and having portions thereof exposed from said mass..]. .[.9. A thermal limiter as set forth in claim 8 wherein said lead means comprise the teeth of a plural circuit wire attachment comb having an electrically insulative base carrying a plurality of electrically conductive wire attachment teeth with wire attaching base supported tooth ends secured to said base and with wire attaching free tooth ends extending away from said base and into said 
     
        mass..]. 10. A thermal limiter as set forth in claim .[.9.]. .Iadd.26 .Iaddend.wherein two supporting wires oppositely extend from said fuse to two of said free tooth ends which define said first pair of lead means, a sleeve of insulative shrink tubing surrounding said fuse with said two supporting wires extending from said sleeve, said tubing being embedded in said mass.  .[.11. A thermal limiter as set forth in claim 8 wherein said heater means comprises another electrical heater disposed in series between one of said first pair of lead means and said fuse..]. .[.12. A thermal limiter as set forth in claim 6 wherein said housing means has means locating said exposed parts of said lead means relative to each 
     
     
        other..]. 13. A thermal limiter as set forth in claim .[.12.]. .Iadd.28 .Iaddend.wherein said locating means space said lead means with at least 
     
     
        one different spacing between adjacent lead means. 14. A thermal limiter as set forth in claim .[.12.]. .Iadd.28 .Iaddend.wherein said locating means comprise a wall of said housing means having a plurality of aligned and spaced pocket means therein respectively receiving said exposed portions of said lead means therein.  .[.15. A method making a thermal limiter for at least one electrical circuit comprising the steps of providing a thermally responsive fuse, operatively interconnecting lead means to said fuse for coupling said fuse in said circuit, disposing an electrical circuit heater means in a selected position relative to said fuse, and covering and securing said heater means and said fuse in said selected positioning thereof with an insulating mass so that said lead means have at least portions thereof exposed from said mass whereby said mass and said selected positioning provides a controlled time delay in said heater means being adapted to cause said fuse to blow and thereby open said one electrical circuit..]. .[.16. A method of making a thermal limiter as set forth in claim 15 and including the step of forming said heater means for a plurality of separate heater wires..]. .[.17. A method of making a thermal limiter as set forth in claim 15 wherein said step of disposing said heater means includes the step of spacing said heater means from said fuse, and disposing said mass between said heater means and said fuse to act as a heat conductor therebetween by said step of covering and securing..]. .[.18. A method of making a thermal limiter as set forth in claim 15 and including the step of forming said heater means from a heater wire and coiling said heater wire on said fuse..]. .[.19. A method of making a thermal limiter as set forth in claim 15 and including the step of forming said heater means from a heater wire and disposing said heater wire in series between one of said lead means and said fuse..]. .[.20. A method of making a thermal limiter as set forth in claim 15 and including the step of providing a housing means to receive said heater means and said fuse therein in said selected positioning therebetween, said mass being disposed in said housing to cooperate with said housing to cover and secure said heater means and said fuse in said selected positioning thereof..]. .Iadd. 21. A thermal limiter for at least one electrical circuit comprising a thermally responsive fuse of generally cylindrical configuration; lead means operatively interconnected to said fuse for coupling said fuse in said circuit; an electrical circuit heater means disposed in a selected position adjacent said fuse in substantially parallel relation therewith and comprising a coiled heater wire having its opposed ends respectively electrically interconnected and securely attached to two lead means comprising blade-like leads positioned in line with the axis of said coil and wrapped at least partially around the ends thereof; a housing means receiving said heater means and said fuse therein in said selected position; and an insulating coating mass disposed in and cooperating with said housing to cover and secure said heater means and said fuse in said selected positioning with all of said lead means having at least portions thereof exposed from said mass; whereby said mass and said selected positioning provides a controlled delay in the time between activating of said heater means and the blowing of said fuse to open said one electrical circuit. .Iaddend. .Iadd. 22. A thermal limiter according to claim 21 wherein one of said blade-like leads is electrically interconnected to one side of said fuse. .Iaddend..Iadd. 23. A thermal limiter according to claim 22 wherein the end of said fuse which is remote from electrical connection to said heater means is connected to a blade-like lead, and said blade-like lead is disposed intermediate aforesaid two blade-like leads and is in alignment therewith. .Iaddend..Iadd. 24. A thermal limiter according to claim 22 wherein said mass is disposed between said heater means and said fuse to act as a heat conductor therebetween. .Iaddend. .Iadd. 25. A thermal limiter for at least one electrical circuit comprising a thermally responsive fuse, a first pair of lead means electrically interconnected to opposed sides of said fuse, an electrical heater means disposed in a selected position relative to said fuse, a second pair of lead means electrically interconnected to opposed sides of said heater means, an insulating coating mass covering and securing said fuse in said selected positioning, and a plural circuit wire attachment comb comprising an electrically insulative base supporting a plurality of electrically conductive wire attachment teeth, said base being spaced apart from said insulating coating mass and said teeth extending away from said base and into said mass for connection to said leads, whereby said mass and said positioning provides a controlled delay in the time between activating of said heater means and the blowing of said fuse to open said one electrical circuit. .Iadd. 26. A thermal limiter for at least one electrical circuit comprising a thermally responsive fuse, lead means operatively interconnected to said fuse for coupling said fuse in said circuit, an electrical heater means disposed in a selected position relative to said fuse, housing means for receiving and positioning said heater means and said fuse and including locating means for exposed parts of said lead means, and an insulating coating mass cooperating with said housing to cover and secure said heater means and said fuse in said selected positioning with all of said lead means having at least portions thereof exposed from said mass whereby said mass and said selected positioning provides a controlled delay in the time between activating of said heater means and the blowing of said fuse to open said one electrical circuit.