Battery pack adaptor with overstress detection circuit

• US 9,871,370 B2
• Filed: 09/01/2015
• Issued: 01/16/2018
• Est. Priority Date: 09/01/2015
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Friedman, Brian E., Gorti, Bhanuprasad V., Held, Christopher R., Moturu, Abhisheka, Varipatis, Michael, Wisniewski, Paul J., Roberts, Michael W.
• Primary Examiner(s): Nguyen, Danny
• Application Number:
  US14/842,220
• Publication Number:
  US 20170063073A1
• Time in Patent Office: 868 Days
• Field of Search: 361 86- 87
• CPC Class Codes: B25F 5/00 Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
• CPC Class Codes: H01M 10/6235 Power tools
• CPC Class Codes: H02H 3/087 for dc applications
• CPC Class Codes: H02H 7/20 for electronic equipment for converters H02H7/10; for electric measuring instruments G01R1/36; for dc voltage or current semiconductor regulators G05F1/569; for amplifiers H03F1/52; for electronic switching circuits H03K17/08
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An adaptor for connecting a power source to a power tool includes a housing having a first end that is configured to connect to a power source and a second end that is configured to connect to a power tool. The adaptor includes a control circuit disposed within the housing. The control circuit is configured to detect an overstress condition in the power tool and to control the power tool responsive to detecting the overstress condition.

Claims

1. An adaptor for connecting a power source to a power tool, the adaptor comprising:

a housing having a first end that is configured to connect to a power source and a second end that is configured to connect to a power tool; and

a control circuit disposed within the housing, wherein the control circuit comprises a microcontroller and a transistor that is operably connected to the microcontroller, the control circuit being configured to;

determine if the power tool is in a pulse width modulation mode,

determine if a current through the transistor is greater than a threshold current limit, and

responsive to determining the power tool is in the pulse width modulation mode and the current is greater than the threshold current limit, open the transistor to prevent current flow from the power source to the power tool.

2. The adaptor of claim 1, wherein:

the first end of the housing is configured to slidably connect with a battery pack; and

the second end of the housing comprises a tower portion that is configured to insertably connect with the power tool.

3. The adaptor of claim 1, wherein the control circuit is configured to detect an overstress condition in the power tool and to control the power tool responsive to detecting the overstress condition by causing the power tool to stop.

4. The adaptor of claim 1, wherein:

the transistor is configured to measure a power source current; and

the microcontroller is configured to control the transistor to cause the power tool to stop in response to the measured current exceeding a threshold current limit.

5. The adaptor of claim 1, wherein the control circuit further comprises a diode that is operably connected between the transistor and a positive leg of the power source.

6. A method for detecting and controlling an overstress condition in a power tool, the method comprising:

detecting an overstress condition in a power tool by a control circuit disposed within a housing of an adaptor, wherein the adaptor is operably connected between a power source and the power tool and the control circuit comprises a microcontroller and a transistor that is operably coupled to the microcontroller and wherein detecting the overstress condition includes;

determining if the power tool is in a pulse width modulation mode, and

determining if a current through the transistor is greater than a threshold current limit; and

controlling the power tool by the control circuit disposed within the housing of the adaptor responsive to detecting the overstress condition in the power tool, wherein controlling the power tool includes responsive to determining the power tool is in the pulse width modulation mode and the current is greater than the threshold current limit, opening the transistor to prevent current flow from the power source to the power tool.

7. The method as in claim 6, wherein controlling the power tool comprises:

causing the power tool to stop responsive to detecting the overstress condition in the power tool.

8. The method as in claim 6, wherein detecting the overstress condition comprises:

measuring a power source current by the control circuit; and

comparing the power source current to a threshold current limit.

9. The method as in claim 8, wherein controlling the power tool comprises:

causing the power tool to stop in response to the measured current exceeding the threshold current limit.

10. A cordless power tool system, comprising:

a cordless power tool configured to receive a power source to power the power tool;

a power source; and

an adaptor for connecting the power source to the cordless power tool, the adaptor comprising;

a housing having a first end that is configured to connect to the power source and a second end that is configured to connect to the cordless power tool; and

a control circuit disposed within the housing, wherein the control circuit comprises a microcontroller and a transistor that is operably connected to the microcontroller, the control circuit being configured to;

determine if the power tool is in a pulse width modulation mode,

determine if a current through the transistor is greater than a threshold current limit, and

responsive to determining the power tool is in the pulse width modulation mode and the current is greater than the threshold current limit, open the transistor to prevent current flow from the power source to the power tool.

11. The cordless power tool system of claim 10, wherein:

the first end of the housing is configured to slidably connect with a battery pack; and

the second end of the housing comprises a tower portion that is configured to insertably connect with the power tool.

12. The cordless power tool system of claim 10, wherein the control circuit is configured to detect an overstress condition in the power tool and to control the power tool responsive to detecting the overstress condition by causing the power tool to stop.

13. The cordless power tool system of claim 10, wherein:

the transistor is configured to measure a power source current; and

the microcontroller is configured to control the transistor to cause the power tool to stop in response to the measured current exceeding a threshold current limit.

14. The cordless power tool system of claim 10, wherein the control circuit further comprises a diode that is operably connected between the transistor and a positive leg of the power source.