Tool with battery pack

• US 7,176,656 B2
• Filed: 06/22/2004
• Issued: 02/13/2007
• Est. Priority Date: 06/22/2004
• Status: Expired due to Fees

• Current Assignee: Campbell Hausfeld/Scott Fetzer Company (Berkshire Hathaway Incorporated)
• Original Assignee: Campbell Hausfeld/Scott Fetzer Company (Berkshire Hathaway Incorporated)
• Inventors: Feldmann, William Mark
• Primary Examiner(s): Easthom; Karl
• Assistant Examiner(s): Berhanu; Samuel
• Application Number:
  US10/873,050
• Publication Number:
  US 20050280393A1
• Time in Patent Office: 966 Days
• Field of Search: 320/111, 320/114, 320/116, 320/117, 320/136, 320120-121, 429/99
• US Class Current: 320/114
• 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: H02J 7/0014 Circuits for equalisation of charge between batteries

Abstract

A handheld tool has an attached position in which the tool is removably attached to a battery pack. The battery pack has an auxiliary battery and output terminals for outputting electricity from the auxiliary battery. The tool includes a load and a primary battery. Input terminals of the tool are configured to connect to the battery output terminals when the tool is in the attached position. A circuit is connected to the load, the primary battery and the input terminals. The circuit is configured to power the load solely from the primary battery when the housing is not in the attached position, and to power the load from both the primary and auxiliary batteries in series when the housing is in the attached position.

Claims

1. A handheld tool comprising:

a load;

a primary battery;

input terminals configured to connect to output terminals of a battery pack that output electricity from an auxiliary battery in the pack; and

a circuit configured to power the load solely from the primary battery when the input terminals are not connected to battery pack output terminals and do not input electricity into the tool, and to switch, automatically and in response to the input terminals being connected to the auxiliary battery output terminals, to powering the load with both the primary and auxiliary batteries electrically in series;

wherein the input and output terminals comprise prongs and jacks, and removably attaching the pack to the tool entails plugging the prongs into the jacks, which immediately places the auxiliary battery in series with the primary battery and the load.

2. The tool of claim 1 further comprising a handheld tool housing, removably attachable to the battery pack, that houses the load, the primary battery and the circuit.

3. An apparatus comprising the tool of claim 1 and the battery pack, wherein, when the tool is removably attached to the pack, the tool and the pack are attached rigidly together to form a tool structure that can be grasped by hand as a single unit.

4. The tool of claim 1 wherein the tool is a drill.

5. The tool of claim 1 wherein the load is a motor.

6. The tool of claim 1 wherein the circuit is configured to monitor, while the tool is powered with both batteries in series, the voltages of the primary and auxiliary batteries individually to determine which, if any, of the two batteries is weak.

7. The tool of claim 6 wherein the circuit is configured to divert current around the weak battery while continuing to power the load through the other battery.

8. The tool of claim 6 wherein the circuit is configured to display an indication of which of the two batteries is weak.

9. The tool of claim 1 wherein the circuit can connect the auxiliary battery user-selectably in series or in parallel with the primary battery and the load when the pack output terminals are connected to the tool input terminals.

10. An apparatus comprising:

a tool having first and second input terminals for inputting electrical current with which to power the tool;

a self-contained first battery pack comprising a first battery, first and second input terminals and first and second output terminals, and configured to be removably attached to the tool with the output terminals of the first pack respectively connected to the tool input terminals to power the tool solely from the first battery by electrons flowing from the first pack into the tool through the first output terminal of the first pack and the first input terminal of the tool and returning into the first pack through the second input terminal of the tool and the second output terminal of the first pack; and

a self-contained second battery pack comprising a second battery and first and second output terminals, and configured to be removably attached to the first pack while the first pack is attached to the tool, with the output terminals of the second pack respectively connected to the input terminals of the first pack for electrons to flow from the second pack into the first pack through the first output terminal of the second pack and the first input terminal of the first pack and to return from the first pack into the second pack through the second input terminal of the first pack and the second output terminal of the second pack, and the output terminals of the first pack respectively connected to the tool input terminals to power the tool with both batteries in series, and the second pack sensing whether the first battery is weak.

11. The apparatus of claim 10 wherein the second pack is configured to sense, while the tool is being powered by both batteries in series, also whether the second battery is weak and to divert the current powering the tool around the weak battery while continuing to power the tool through the battery that is not weak.

12. A handheld tool comprising:

a load;

a primary battery;

input terminals configured to connect to output terminals of a battery pack that output electricity from an auxiliary battery in the pack; and

a circuit configured to power the load solely from the primary battery when the input terminals are not connected to battery pack output terminals and do not input electricity into the tool, and to switch, automatically and in response to the input terminals being connected to the auxiliary battery output terminals, to powering the load with both the primary and auxiliary batteries electrically in series;

wherein the circuit is configured to short the input terminals together when the input terminals are not connected to an external power source and to remove the short in response to the input terminals being electrically connected to the auxiliary battery output terminals.

13. The tool of claim 12 further comprising a handheld tool housing, removably attachable to the battery pack, that houses the load, the primary battery and the circuit.

14. An apparatus comprising the tool of claim 12 and the battery pack, wherein, when the tool is removably attached to the pack, the tool and the pack are attached rigidly together to form a tool structure that can be grasped by hand as a single unit.

15. The tool of claim 12 wherein the tool is a drill.

16. The tool of claim 12 wherein the load is a motor.

17. The tool of claim 12 wherein the circuit is configured to monitor, while the tool is powered with both batteries in series, the voltages of the primary and auxiliary batteries individually to determine which, if any, of the two batteries is weak.

18. The tool of claim 17 wherein the circuit is configured to divert current around the weak battery while continuing to power the load through the other battery.

19. The tool of claim 17 wherein the circuit is configured to display an indication of which of the two batteries is weak.

20. The tool of claim 12 wherein the circuit can connect the auxiliary battery user-selectably in series or in parallel with the primary battery and the load when the pack output terminals are connected to the tool input terminals.