Power tool including a fuel gauge and method of operating the same

• US 7,649,337 B2
• Filed: 05/17/2006
• Issued: 01/19/2010
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Original Assignee: Milwaukee Electric Tool Corporation (Techtronic Industries Company Limited)
• Inventors: Mergener, Matthew J., Uehlein-Proctor, Nancy, Holly, Jeffrey S.
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US11/435,596
• Publication Number:
  US 20060267556A1
• Time in Patent Office: 1,343 Days
• Field of Search: 320/107, 320112-116, 320/101, 439/155, 439/352, 439/500, 439/929, 814/73, 324/432, 324/434, 324/435
• US Class Current: 320/112
• 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

Abstract

A power tool and a method of operating a power tool. The power tool can include a housing supporting a motor, a switch assembly, and a fuel gauge. The method can include the acts of activating the switch assembly to electrically connect the motor and a battery, measuring a state of charge of the battery, displaying the state of charge on the fuel gauge before electrically connecting the motor and the battery, and stopping the display of the state of charge before deactivating the switch assembly.

Claims

1. A method of operating a power tool, the power tool including a housing supporting a motor, a switch assembly, and a fuel gauge, the method comprising the acts of:

activating the switch assembly to electrically connect the motor and a battery;

measuring a state of charge of the battery;

displaying the state of charge on the fuel gauge by activating the switch assembly, the state of charge being measured as the switch assembly is activated and before the motor is electrically connected to the battery; and

stopping the display of the state of charge before deactivating the switch assembly.

2. The method of claim 1, wherein displaying the state of charge includes displaying an at rest state of charge of the battery.

3. The method of claim 1, wherein displaying the state of charge includes displaying the state of charge on the fuel gauge for about 2 seconds after activating the switch assembly.

4. The method of claim 1, further comprising operating the motor, wherein the state of charge of the battery changes during operation of the motor, and wherein, during operation of the motor, the fuel gauge continually displays the state of charge measured before operation of the motor.

5. The method of claim 1, further comprising calculating a second state of charge of the battery, the second state of charge being different than the first state of charge;

and displaying the second state of charge before reconnecting the motor and the battery.

6. The method of claim 1, further comprising alerting an operator when the motor is overloaded.

7. The method of claim 6, wherein alerting the operator includes activating the display.

8. The method of claim 6, further comprising stopping the motor when the motor is overloaded.

9. A method of operating a power tool, the power tool including a housing supporting a motor and a fuel gauge, the method comprising the acts of:

connecting a battery to the housing, the battery having an at rest state of charge, the at rest state of charge being a state of charge of the battery before the battery is affected by current draw from the motor;

displaying the at rest state of charge of the battery on the fuel gauge; and

activating the motor and continuing to display the at rest state of charge of the battery on the fuel gauge as the battery powers the motor.

10. The method of claim 9, wherein the power tool includes a switch assembly supportable on the housing and operable to electrically connect the motor and the battery, and further comprising moving at least a portion of the switch assembly relative to the housing to measure the at rest state of charge of the battery.

11. The method of claim 10, wherein moving the portion of the switch assembly relative to the housing includes electrically connecting the motor and the battery with the switch assembly, and further comprising removing the at rest state of charge from the fuel gauge before electrically disconnecting the battery and the motor with the switch assembly.

12. The method of claim 9, wherein displaying the at rest state of charge of the battery on the fuel gauge includes displaying the at rest state of charge of the battery before activating the motor.

13. The method of claim 9, wherein the power tool includes a switch assembly supportable on the housing and operable to electrically connect the motor to the battery, and wherein displaying the at rest state of charge of the battery on the fuel gauge includes displaying the at rest state of charge for approximately 2 seconds after moving at least a portion of the switch assembly with respect to the housing.

14. The method of claim 9, further comprising alerting an operator when the motor is overloaded.

15. The method of claim 14, wherein alerting the operator includes displaying an alert on the fuel gauge.

16. The method of claim 14, further comprising deactivating the motor when the motor is overloaded.

17. The method of claim 14, further comprising stopping the display of the at rest state of charge of the battery on the fuel gauge before deactivating the motor.

18. The method of claim 9, further comprising operating the motor and changing a state of charge of the battery, and wherein continuing to display the at rest state of charge of the battery includes displaying the at rest state of charge recorded before operating the motor.

19. A power tool comprising:

a movable spindle for supporting a tool element;

a housing supporting a motor and a drive mechanism driven by the motor, the drive mechanism being operably connected to the spindle for causing movement of the spindle relative to the housing, the housing having a forward end supporting the spindle and a rearward end;

a battery connectable to the rearward end;

a fuel gauge supported on the housing for displaying an at rest state of charge of the battery, the at rest state of charge being a state of charge of the battery before the battery is affected by current draw from the motor; and

a switch assembly operable to electrically connect the motor and the battery and activate the fuel gauge to display the at rest state of charge of the battery.

20. The power tool of claim 19, wherein the fuel gauge is operable to display the at rest state of charge during continued operation of the motor.

21. The power tool of claim 19, wherein the fuel gauge is operable to display the at rest charge for approximately 2 seconds after activation of the motor.