Driver

1. A driver comprising:

a striking unit configured to be movable in a first direction and a second direction that is opposite to the first direction;

a first bias unit configured to move the striking unit in the first direction so that a fastener is struck by the striking unit;

a first operational unit configured to be operated by an operator;

a second operational unit configured to be pressed against a workpiece to which the fastener is struck; and

a control unit configured to move the striking unit in the first direction by using the first bias unit when the control unit detects the operation of the first operational unit and the pressing of the second operational unit against the workpiece,

wherein the control unit is configured to control the driver in a first driving mode or a second driving mode in response to selection by the operator,

wherein the control unit is configured to execute,

the first driving mode causing the striking unit to perform a single driving operation when the control unit detects both the operation of the first operational unit and the operation of the second operational unit, and

the second driving mode causing the striking unit to perform a driving operation every time when the second operational unit is operated while the first operational unit remains operated by the operator, and

wherein the control unit further includes a limitation mode in which;

(1) after a driving operation in response to operation of the second operational unit in the second driving mode, the control unit terminates the second driving mode; or

(2) the control unit maintains the first driving mode that is automatically selected when the driver is activated, without allowing the operator to select the second mode.

2. The driver according to claim 1 ,

wherein the control unit automatically selects the limitation mode when determining an abnormal state.

3. The driver according to claim 2 ,

wherein a second bias unit configured to move the striking unit in the second direction is arranged,

the control unit is configured to move the striking unit stopping at a predetermined position in the second direction by using the second bias unit, and then, to move the striking unit in the first direction by using the first bias unit so that the fastener is struck by the striking unit, and besides, to move the striking unit in the second direction by using the second bias unit to return the striking unit to the predetermined position, and

the control unit determines the abnormal state on the basis of operational time taken from a moment of start of the movement of the striking unit stopping at the predetermined position in the second direction through a moment of the striking of the fastener by the striking unit to a moment of the movement of the striking unit in the second direction and arrival of the striking unit at the predetermined position.

4. The driver according to claim 2 , further comprising a second bias unit configured to move the striking unit in the second direction,

wherein the second bias unit has:

an electric motor configured to be rotated by supply of power thereto;

a power supply configured to supply the power to the electric motor; and

a power transmission mechanism configured to move the striking unit in the second direction by using a torque of the electric motor.

5. The driver according to claim 4 ,

wherein the power supply is a storage battery, and

the control unit determines the abnormal state on the basis of a voltage of the storage battery.

6. The driver according to claim 4 ,

wherein the control unit determines the abnormal state on the basis of a current value of the power supply.

7. The driver according to claim 4 ,

wherein the control unit determines the abnormal state on the basis of a temperature of the power supply.

8. The driver according to claim 4 ,

wherein the control unit determines the abnormal state on the basis of a usage history of the power supply.

9. The driver according to claim 1 further comprising

a display unit displaying which one of the first driving mode, the second driving mode and the limitation mode is being operated.

10. A driver comprising:

a striking unit configured to be movable in a first direction and a second direction that is opposite to the first direction;

an electric motor configured to move the striking unit in the second direction by using power of a power supply;

a first bias unit configured to move the striking unit in the first direction so that a fastener is struck by the striking unit;

a first operational unit configured to be operated by an operator;

a second operational unit configured to be operated by the operator and pressed against a workpiece to which the fastener is struck; and

a control unit configured to move the striking unit in the first direction by using the first bias unit when the control unit detects the operation of the first operational unit and the pressing of the second operational unit against the workpiece,

wherein the control unit can execute;

a first driving mode performing a driving operation moving the striking unit in the first direction by using the first bias unit when the control unit detects the operation of the first operational unit after the pressing of the second operational unit against the workpiece, and

a second driving mode performing a driving operation moving the striking unit in the first direction by using the first bias unit so that the fastener is struck when the control unit detects the operation of the first operational unit and the pressing of the second operational unit against the workpiece, and

wherein the control unit monitors a state of the power supply, and when determining that the power supply is in an abnormal state, the control unit prohibits the driving operation in the second driving mode selected by the operator and permits the driving operation in the first driving mode selected by the operator.

11. A driver comprising:

a striking unit configured to be movable in a first direction and a second direction that is opposite to the first direction;

an electric motor;

a power transmission mechanism configured to convert a torque of the motor into a moving force of the striking unit;

a battery configured to supply the power to the motor;

a first operational unit configured to be operated by an operator;

a second operational unit configured to be pressed against a workpiece to which the fastener is struck; and

a control unit configured to control the motor,

wherein, by an operation of the operator, the control unit can execute;

a first driving mode performing a driving operation moving the striking unit in the first direction when the control unit detects the operation of the first operational unit after the pressing of the second operational unit against the workpiece, and

a second driving mode performing a driving operation moving the striking unit in the first direction so that the fastener is struck when the control unit detects the operation of the first operational unit and the pressing of the second operational unit against the workpiece, and

wherein the control unit monitors a state of the battery, and when determining that the battery is in an abnormal state, the control unit prohibits the driving operation in the second driving mode selected by the operator and permits the driving operation in the first driving mode selected by the operator.

12. A driver comprising:

a striking unit configured to be movable in a first direction and a second direction that is opposite to the first direction;

a first bias unit configured to move the striking unit in the first direction so that a fastener is struck by the striking unit;

a first operational unit configured to be operated by an operator;

a second operational unit configured to be pressed against a workpiece to which the fastener is struck; and

a control unit configured to move the striking unit in the first direction by using the first bias unit when the control unit detects the operation of the first operational unit and the pressing of the second operational unit against the workpiece,

wherein the control unit is configured to control the driver in a first driving mode or a second driving mode in response to selection by the operator,

wherein the control unit is configured to execute;

the first driving mode causing the striking unit to perform a single driving operation when the control unit detects both the operation of the first operational unit and the operation of the second operational unit, and

the second driving mode causing the striking unit to perform a driving operation every time when the second operational unit is operated while the first operational unit remains operated by the operator, and

wherein the control unit changes the driving mode from the second driving mode to the first driving mode without the selection by the operator when detecting an abnormal state in the second driving mode.