Electric wheeled apparatus

1. An electric wheeled apparatus comprising:

a main body;

at least one wheel supported by the main body in a rotatable manner;

an electric motor configured to apply torque to the at least one wheel;

a battery interface configured to removably receive at least first battery pack and a second battery pack which are each originally designed as a power source of an electric power tool, wherein the battery interface is configured to receive the first and second battery packs while the first and second battery packs are detached from the power tool; and

an electric circuit unit configured to electrically connect the first and second battery packs attached to the battery interface with the electric motor,

wherein the battery interface comprises a first positive connection terminal, a first negative connection terminal, a second positive connection terminal and a second negative connection terminal,

the first positive connection terminal and the first negative connection terminal are configured to be electrically connected with a positive terminal and a negative terminal of the first battery pack respectively when the first battery pack is attached to the battery interface,

the second positive connection terminal and the second negative connection terminal and configured to be electrically connected with a positive terminal and a negative terminal of the second battery pack respectively when the second battery pack is attached to the battery interface, and

the electric unit is configured to selectively be switched to form a series connection circuit in which the first positive connection terminal is electrically connected with the second negative connection terminal with the electric motor being electrically interposed in the connection circuit between the first positive connection terminal and the second negative connection terminal, and in which the first negative connection terminal is electrically connected with the second positive connection terminal without the electric motor being electrically interposed in the connection circuit between the first negative connection terminal and the second positive connection terminal, and

the electric circuit unit is further configured to selectively be switched to form any one of the series connection circuit and a parallel connection circuit in which the first positive connection terminal is electrically connected with the second positive connection terminal without the electric motor being electrically interposed in the connection circuit between the first positive connection terminal and the second positive connection terminal, and in which the first negative connection terminal is electrically connected with the second negative connection terminal without the electric motor being electrically interposed in the connection circuit between the first negative connection terminal and the second negative connection terminal.

2. The electric wheeled apparatus as in claim 1 , wherein the electric wheeled apparatus is an electric bicycle, which further comprises:

pedals configured to be pedaled by a user on the electric bicycle; and

a user force transmission configured to mechanically connect the pedals with the at least one wheel so as to transmit force applied to the pedals by the user to the at least one wheel.

3. The electric wheeled apparatus as in claim 2 , wherein the electric circuit unit is configured to control electric power supply from the first and second battery packs to the electric motor in accordance with the force applied to the pedals by the user.

4. The electric wheeled apparatus as in claim 1 , wherein

the electric wheeled apparatus is a carrier cart,

the main body has a platform configured to support baggage,

the at least one wheel includes a pair of wheels; and

the battery interface is arranged such that the first and second battery packs are partly located between the pair of wheels when the first and second battery packs are attached to the battery interface.

5. The electric wheeled apparatus as in claim 4 , wherein the electric circuit unit is configured to control electric power supply to the electric motor in accordance with a force applied to the carrier cart by a user.

6. The electric wheeled apparatus as in claim 1 , wherein

the electric apparatus is a wheelbarrow,

the at least one wheel is a single wheel and

the electric motor is an in-wheel incorporated in the single wheel.

7. The electric wheeled apparatus as in claim 6 , wherein the electric circuit unit is configured to control electric power supply to the electric motor in accordance with a force applied to the wheelbarrow by a user.

8. The electric wheeled apparatus as in claim 1 , wherein

the electric wheeled apparatus is a suitcase,

the main body is an openable case that supports the at least one wheel driven by the electric motor, and

the battery interface is arranged within the openable case such that the first and second battery packs are able to be attached to and detached from the battery interface from inside the openable case.

9. The electric wheeled apparatus as in claim 8 , wherein the electric circuit unit is configured to control electric power supply to the electric motor in accordance with a force applied to the suitcase by a user.

10. The electric wheeled apparatus as in claim 1 , wherein

the electric wheeled apparatus is an electric power mower having a cutter, and

the electric motor is configured to apply torque to both of the at least one wheel and the cutter.

11. The electric wheeled apparatus as in claim 10 , wherein the electric circuit unit is configured to control electric power supply to the electric motor in accordance with a force applied to the electric power mower by a user.

12. The electric wheeled apparatus as in any claim 1 , wherein

the electric wheeled apparatus is an electric power cultivator having a cultivating rotor, and

the electric motor is configured to apply torque to both of the at least one wheel and the cultivating rotor.

13. The electric wheeled apparatus as in claim 12 , wherein the electric circuit unit is configured to control electric power supply to the electric motor in accordance with a force applied to the electric power cultivator by a user.

14. A combination comprising:

an electric power tool;

at least a first battery pack and a second battery pack each configured to be detachably attached to the electric power tool;

a charger configured to electrically connect to and recharge the first and second battery packs; and

the electric wheeled apparatus as in claim 1 , the battery interface of which is configured to removably receive the first and second battery packs while the first and second battery packs are detached from the electric power tool.

15. The electric wheeled apparatus as in claim 1 , wherein the electric circuit unit comprises a first selection switch configured to selectively electrically connect the first negative connection terminal with any one of the second positive connection terminal and the second negative connection terminal, without the electric motor being electrically interposed in the connection circuit between the first negative connection terminal and the any one of the second positive connection terminal and the second negative connection terminal.

16. The electric wheeled apparatus as in claim 1 , wherein the battery interface is configured to removably receive a third battery pack which is originally designed as a power source of the electric power tool, wherein the battery interface is configured to receive the third battery pack while the third battery pack is detached from the power tool,

the battery interface further comprises a third positive connection terminal and a third negative connection terminal which are configured to be electrically connected with a positive terminal and a negative terminal of the third battery pack respectively when the third battery pack is attached to the battery interface, and

when the electric circuit unit forms the series connection circuit, the third positive connection terminal is electrically connected with the second negative connection terminal without the electric motor being electrically interposed in the connection circuit between the third positive connection terminal and the second negative connection terminal, and the third negative connection terminal is electrically connected with the first positive connection terminal with the electric motor being electrically interposed in the connection circuit between the third negative connection terminal and the first positive connection terminal.

17. The electric wheeled apparatus as in claim 16 , wherein the electric circuit unit is further configured to selectively be switched to form any one of the series connection circuit and the parallel connection circuit in which the first positive connection terminal is electrically connected with both the second and third positive connection terminals without the electric motor being electrically interposed in the connection circuit between the first positive connection terminal and either of the second and third positive connection terminals, and the first negative connection terminal is electrically connected with both the second and third negative connection terminals without the electric motor being electrically interposed in the connection circuit between the first negative connection terminal and either of the second and third positive negative connection terminals.

18. The electric wheeled apparatus as in claim 1 , wherein the electric circuit unit comprises a first selection switch and a second selection switch, the first selection switch is configured to selectively electrically connect the first negative connection terminal, with any one of the second positive connection terminal and the third negative connection terminal, without the electric motor being electrically interposed in the connection circuit between the first negative connection terminal and the any one of the second positive connection terminal and the third negative connection terminal, and the second selection switch is configured to selectively electrically connect the second negative connection terminal, with any one of the third positive connection terminal and the third negative connection terminal, without the electric motor being electrically interposed in the connection circuit between the second negative connection terminal and the any one of the third positive connection terminal and the third negative connection terminal.