Low magnetic field emitting electric blanket

• US 6,153,856 A
• Filed: 11/16/1998
• Issued: 11/28/2000
• Est. Priority Date: 01/21/1997
• Status: Expired due to Term

• Current Assignee: Myoung Jun Lee
• Original Assignee: Myoung Jun Lee
• Inventors: Lee, Myoung Jun
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): DAHBOUR, HENRY
• Application Number:
  US09/192,957
• Time in Patent Office: 743 Days
• Field of Search: 219/212, 219/528, 219/529, 219/538, 219/544, 219/546, 219/548, 219/549, 219/552, 338/214, 338/299, 338/302, 338/303, 338/321
• US Class Current: 219/212
• CPC Class Codes: H05B 1/0272 For heating of fabrics
• CPC Class Codes: H05B 2203/004 using zigzag layout
• CPC Class Codes: H05B 2203/014 Heaters using resistive wires or cables not provided for in H05B3/54
• CPC Class Codes: H05B 2203/017 Manufacturing methods or apparatus for heaters
• CPC Class Codes: H05B 3/342 heaters used in textiles

Abstract

An electric blanket used with a source voltage has a control device connected to the source voltage to control the source voltage in response to a predetermined temperature setting and a heating pad having a heating element arranged in the heating pad and connected to the output of the control device to generate heat. The heating element includes a first core, a first conductive element spirally wound around the first core, a second core arranged in surrounding relation to the first core and the first conductive element and a second conductive element spirally wound around the second core. The first ends of the first and second conductive elements are connected to the output of the control device and the second ends are connected to each other to define a conductive loop. The heating element further comprises an outer cover that covers the second core and the second conductive element and shields the internal components from external environment. The first conductive element comprises a third core and a conductive wire spirally wound around the third core. The conductive wire generates heat when electricity is applied.

Claims

1. An electric blanket for use with an ungrounded source voltage, comprising:

a control device connected to the source voltage to control the source voltage in response to a predetermined temperature setting; and

a heating pad having a heating element arranged in the heating pad and connected to an output of the control device to generate heat, the heating element including;

a first core;

a first conductive element wound around the first core using the first core as an axis;

a second core arranged in surrounding relation to the first core and the first conductive element; and

a second conductive element wound around the second core using the second core as an axis, wherein the first and the second conductive elements are electrically connected to each other at one end and are connected to the ungrounded source voltage at the other end to at least partially cancel out magnetic field generated from each conductive element.

2. The electric blanket of claim 1, the heating element further comprising an outer cover that covers the second core and the second conductive element.

3. The electric blanket of claim 1, wherein each one of the first and second conductive elements comprises:

a third core;

a conductive wire wound around the third core using the third core as an axis, wherein the conductive wire generates heat when electricity is applied.

4. The electric blanket of claim 3, wherein the third core is made of a cotton strand.

5. The electric blanket of claim 3, wherein the conductive wire is made with copper having a non-conductive coating.

6. The electric blanket of claim 1, wherein the first and second cores are made of a non-conductive material with a high heat transmitting coefficient.

7. The electric blanket of claim 6, wherein the first core is made with silicone.

8. The electric blanket of claim 6, wherein the second core is made with silicone.

9. The electric blanket of claim 1, the electric blanket further including an A/C to D/C converter arranged between the control device and the heating pad to provide a D/C voltage to the heating pad.

10. The electric blanket of claim 1, the heating pad further comprising a shield arranged to cover the heating element, wherein the shield is a wire mesh made of conductive wire.

11. The electric blanket of claim 1, the heating pad further comprising a shield arranged to cover the heating element, wherein the shield is a conductive sheet.

12. The electric blanket of claim 1, wherein first ends of the first and second conductive elements are connected to the output of the control device and the second ends are connected to each other to define a conductive loop.

13. A heating element for use in an electric blanket with a source voltage, the heating element comprising:

a first core;

a first conductive element wound around the first core using the first core as an axis;

a second core arranged in surrounding relation to the first core and the first conductive element; and

a second conductive element wound around the second core using the second core as an axis, wherein the first and the second conductive elements are electrically connected to each other at one end and are connected to the source voltage at the other end.

14. The heating element of claim 13, the heating element further comprising an outer cover that covers the second core and the second conductive element.

15. The heating element of claim 13, wherein each one of the first and second conductive elements comprises:

a third core;

a conductive wire wound around the third core using the third core as an axis, wherein the conductive wire generates heat when electricity is applied.

16. The heating element of claim 15, wherein the third core is made of a cotton strand.

17. The heating element of claim 15, wherein the conductive wire is made with copper having a non-conductive coating.

18. The heating element of claim 13, wherein the first and second cores are made of a non-conductive material with a high heat transmitting coefficient.

19. The heating element of claim 18, wherein the first core is made with silicone.

20. The heating element of claim 19, wherein the second core is made with silicone.