Resistance measurement tool

• US 10,209,286 B2
• Filed: 02/15/2016
• Issued: 02/19/2019
• Est. Priority Date: 02/15/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Weber, David Charles, Mahoney, Mark Milton, Strachan, Jonathan
• Primary Examiner(s): Hollington, Jermele M
• Assistant Examiner(s): Nasir, Taqi
• Application Number:
  US15/043,787
• Publication Number:
  US 20170234917A1
• Time in Patent Office: 1,100 Days
• Field of Search: 324549, 324691, 324 99 D, 324103 R, 324103 P, 324122, 324522, 324399, 324402, 324519, 324525, 324532, 324628
• CPC Class Codes: G01R 27/02 Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant by measuring phase angle only G01R25/00
• CPC Class Codes: G01R 27/14 Measuring resistance by measuring current or voltage obtained from a reference source G01R27/16, G01R27/20, G01R27/22 take precedence
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72

Abstract

A tool to measure resistance of a wire harness is disclosed herein. An example disclosed tool includes a connector with first and second plugs. The example disclosed tool also includes a resistor. A first terminal of the resistor is electrically coupled to the first plug. Additionally, the example disclosed tool includes a thermal switch attached to the resistor with a thermally conductive adhesive. A first terminal of the thermal switch is electrically coupled to a second terminal of the resistor, and a second terminal of the thermal switch is electrically coupled to the second plug.

Claims

1. A tool for measuring resistance of a wire harness comprising;

a connector having first and second plugs;

a resistor electrically coupled to the first plug; and

a thermal switch electrically coupled between the resistor and the second plug, wherein a node between the resistor and the thermal switch is only shared by the resistor and the thermal switch.

2. The tool of claim 1, wherein the connector is a dual-pin banana plug.

3. The tool of claim 1, wherein the resistor is a power resistor.

4. The tool of claim 1, wherein the resistor has an impedance value between two to ten ohms.

5. The tool of claim 1, wherein the thermal switch is a normally-closed switch.

6. The tool of claim 1, wherein the thermal switch has a trigger threshold between 57 degrees Celsius and 63 degrees Celsius.

7. The tool of claim 6, wherein the thermal switch has a reset threshold 17 degrees below the trigger threshold.

8. The tool of claim 1, further including a heat shrink casing around the resistor and the thermal switch.

18. The tool of claim 1, wherein the thermal switch is to switch open when a temperature of a surface of the resistor to which the thermal switch is directly attached to is greater than a trigger threshold temperature.

19. The tool of claim 1, wherein the resistor and the thermal switch are electrically coupled in series.

20. The tool of claim 1, wherein a node shared by the first plug and the resistor is only shared by the first plug and the resistor, and wherein a node shared by the second plug and the thermal switch is only shared by the second plug and the thermal switch.

9. A resistance measurement tool comprising;

a connector having first and second plugs;

a resistor having a first terminal electrically coupled to the first plug, the resistor to generate heat when the resistance measurement tool is connected to a vehicle power bus;

a first switch having a first terminal electrically coupled to a second terminal of the resistor;

thermally conductive adhesive between the first switch and the resistor that attaches the first switch directly to the resistor; and

a second switch attached to the resistor, a first terminal of the second switch electrically coupled to a second terminal of the first switch, a second terminal of the second switch electrically connected to the second plug, wherein a node between the resistor and the second switch is only shared by the resistor and the second switch.

10. The resistance measurement tool of claim 9, wherein the connector is a dual-pin banana plug.

11. The resistance measurement tool of claim 9, wherein the resistor is a power resistor.

12. The resistance measurement tool of claim 9, wherein the resistor has an impedance value between two to ten ohms.

13. The resistance measurement tool of claim 9, wherein the first switch is a push-button switch.

14. The resistance measurement tool of claim 9, wherein the second switch is a normally-closed thermal switch.

15. The resistance measurement tool of claim 14, wherein the second switch has a trigger threshold between 57 degrees Celsius and 63 degrees Celsius.

16. The resistance measurement tool of claim 15, wherein the thermal switch has reset threshold 17 degrees below the trigger threshold.

17. The resistance measurement tool of claim 9, further including a heat shrink casing around the resistor and the thermal switch.

21. The tool of claim 9, wherein the resistor, first switch, the second switch are electrically coupled in series.

22. The tool of claim 9, wherein a node between the first switch and the second switch is only shared by the first switch and the second switch.