Power tool charging system having a charge level indicator and charge control functions

• US 6,229,280 B1
• Filed: 03/18/1999
• Issued: 05/08/2001
• Est. Priority Date: 03/18/1998
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company), Makita Corporation
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company), Makita Corporation
• Inventors: Muramatsu, Tomoo, Sakoh, Masahiko, Matsunaga, Yutaka, Sugiura, Masatoshi, Horikawa, Kazuyoshi
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/272,638
• Time in Patent Office: 782 Days
• Field of Search: 320/106, 320/127, 320/128, 320/132, 320/149, 320/150, 320/153, 320/114, 320/DIG. 21, 320/110
• US Class Current: 320/106
• CPC Class Codes: G01R 31/3646 for indicating electrical conditions or variables, e.g. visual or audible indicators
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/007194 of the battery

Abstract

A charging system includes an electric power tool (2) and a charger (1) having internal rechargeable batteries (6) and a controller (9) for monitoring the charge/discharge level of the batteries (6). The electric power tool (2) additionally includes a pair of charge terminals (13a, 14a) for carrying current to charge the batteries (6), a temperature terminal (15a) for outputting to the charger (1) data on the temperature of the batteries, and a data terminal (16a) for outputting to the charger data on the battery charge/discharge level from the controller (9). The charger (1) includes a pair of charge terminals (13b, 14b), a temperature terminal (15b), and a data terminal (16b) that are electrically connected to the corresponding tool terminals when the tool (2) is set on the charger for a charge. The charging system indicates the remaining charge level on an indicator unit (4) based on the received data on the battery charge/discharge level and changes the amount of the charging current based on the data on the battery charge/discharge level and the battery temperature data received from the tool (2).

Claims

1. A power tool charging system, comprising:

an electric power tool including,

at least one rechargeable battery on which the electric power tool operates,

a controller for monitoring charge/discharge level of the at least one battery and for generating data on the charge/discharge level of the at least one battery and

a data transmission terminal for externally providing the data on the charge/discharge level of the at least one battery; and

a charger on which the electric power tool is set for charging the at least one battery, the charger supplying charging current to the at least one battery when the electric power tool is set on the charger.

2. A charging system in accordance with claim 1, wherein the charger further includes a data receive terminal which is connected to the data transmission terminal of the electric power tool when the electric power tool is set on the charger, the data receive terminal receiving the data on the charge/discharge level of the at least one battery from the controller and changing the amount of the charging current based on the charge/discharge level data.

3. A charging system in accordance with claim 2, wherein the charger further includes an indicator means for indicating the remaining charge of the at least one battery based on the charge/discharge level data received from the controller.

4. A charging system in accordance with claim 1, wherein the electric power tool further includes a temperature sensor for measuring and generating data on the temperature of the at least one battery, and a temperature transmission terminal for externally providing the data on the measured battery temperature.

5. A charging system in accordance with claim 4, wherein the charger further includes a temperature receive terminal which is connected to the temperature transmission terminal when the electric power tool is set on the charger, the charger having means for reading the battery temperature and changing the amount of the charging current based on the battery temperature.

6. A charging system in accordance with claim 5, wherein the amount of the charging current supplied by said charger is changed to zero amperes.

7. A charging system in accordance with claim 2, wherein the amount of the charging current supplied by said charger is changed to zero amperes.

8. A charging system in accordance with claim 3, wherein the amount of the charging current supplied by said charger is changed to zero amperes.

9. A charging system in accordance with claim 6, wherein the charger is adapted to increase the amperage of the charging current to the level prior to the decrease to zero amperes once the temperature of the battery decreases to a predetermined level.

10. A charging system in accordance with claim 6, further comprising means for determining the electric power tool is disposed on the charger for charging when the charger reads the battery temperature by receiving data on the battery temperature at the temperature receive terminal.

11. A charging system in accordance with claim 6, wherein the charger further includes a pair of first charge terminals for supplying the charging current to the at least one battery and the electric power tool further includes a pair of second charge terminals that are connected to the at least one battery and that establish contact with the first charge terminals when the electric power tool is set on the charger, and further wherein the at least one battery is determined to be fully charged when the voltage between the second charge terminals exceeds a predetermined first threshold, thus shutting off the charging current, and the at least one battery is defective when the voltage between the second charge terminals is no higher than a predetermined second threshold, thus shutting off the charging current.

12. A charging system in accordance with claim 11, wherein the terminals of the electric power tool are provided thereon in proximity to one another, and the terminals of the charger are provided thereon in proximity to one another so as to establish electrical contact with the corresponding terminals of the electric power tool when the tool is set on the charger for charging the at least one battery.

13. A charging system in accordance with claim 2, wherein the electric power tool further comprises a temperature sensor for measuring and generating data on the temperature of the battery, and a temperature transmission terminal for externally providing the data on the battery temperature.

14. A charging system in accordance with claim 3, wherein the electric power tool further comprises a temperature sensor for measuring and generating data on the temperature of the battery, and a temperature transmission terminal for externally providing the data on the battery temperature.

15. A charging system in accordance with claim 7, wherein the charger is adapted to increase the amperage of the charging current to the level prior to the decrease to zero amperes once the temperature of the battery decreases to a predetermined level.

16. A charging system in accordance with claim 8, wherein the charger is adapted to increase the amperage of the charging current to the level prior to the decrease to zero amperes once the temperature of the battery decreases to a predetermined level.

17. A power tool charging system, comprising

a power tool including,

at least one rechargeable battery housed within the power tool for supplying power to said power tool,

a controller for monitoring a condition of said at least one battery and for generating data based on said condition of said at least one battery, and

a data transmission terminal for externally providing the data on said condition of said at least one battery;

and

an external charger housed separately from said power tool and upon which said power tool is set for charging the at least one battery, the external charger supplying charging current to the at least one battery when the power tool is set on the charger.

18. The charging system of claim 17, wherein said condition monitored by said controller is the charge/discharge level of said at least one battery.

19. The charging system of claim 17, where said condition monitored by said controller is the temperature of said at least one battery.

20. The charging system of claim 17, wherein the external charger includes a data receive terminal for connecting to the data transmission terminal of said power tool.

21. The charging system of claim 20, wherein the external charger includes a receiving recess within which said data receive terminal is positioned, said receiving recess being sized and shaped to receive a portion of said power tool having said data transmission terminal.

22. A power tool charging system, comprising

an electric power tool including,

at least one rechargeable battery on which the electric power tool operates,

a controller for monitoring charge/discharge level of the at least one battery and for generating data on the charge/discharge level of the at least one battery,

a data transmission terminal for externally providing the data on the charge/discharge level of the at least one battery,

a temperature sensor for measuring and generating data on the temperature of the at least one battery, and

a temperature transmission terminal for externally providing the data on the measured battery temperature;

and

a charger upon which the electric power tool is set for charging the at least one battery, the charger supplying charging current to the at least one battery when the electric power tool is set on the charger, the charger including,

a data receive terminal which is connected to the data transmission terminal of the electric power tool when the electric power tool is set on the charger, the data receive terminal receiving the data on the charge/discharge level of the at least one battery from the controller, the charger operating to change the amount of charging current based on the charge/discharge level data, and

a temperature receive terminal which is connected to the temperature transmission terminal of the electric power tool when the electric power tool is set on the charger, the temperature receive terminal receiving the measured battery temperature from the temperature sensor, the charger operating to change the charging current based on the measured battery temperature.

23. A charging system in accordance with claim 22, wherein the amount of charging current is changed to zero amperes in response to the charge/discharge level data.

24. A charging system in accordance with claim 22, wherein the amount of charging current is changed to zero amperes in response to the measured battery temperature.