Electric screwdriver and a controller thereof

An electric screwdriver device comprising an electric screwdriver and a controller connected to said electric screwdriver, in which

• said controller comprises:
• a power source and a power circuit for said power source, said power circuit having a function for selectively providing an output for a normal rotation from said power source or an output for a reverse rotation from said power source in accordance with a normal rotation signal or a reverse rotation signal given by said electric screwdriver and for shutting down an output from said power source in accordance with a stop signal of said electric screwdriver or a tightening completion signal generated by said electric screwdriver;
• and
• a tightening completion signal and reverse rotation signal processing unit for processing said tightening completion signal and said reverse rotation signal, and
• said electric screwdriver comprises:
• a screwdriver motor to be connected to the power source terminals of said power circuit;
• a common line for supplying a reference voltage;
• a normal-rotation/reverse-rotation shifting switch for shifting between the normal-rotation and the reverse-rotation of the screwdriver motor;
• a first signal line for interconnecting a first output terminal of said normal-rotation/reverse-rotation shifting switch and said controller;
• a second signal line for interconnecting a second output terminal of said normal-rotation/reverse-rotation shifting switch and said controller;
• a starting switch connected between said common line and a first input terminal of said normal-rotation/reverse-rotation shifting switch;
• and
• a braking switch connected between said starting switch and a second input terminal of said normal-rotation/reverse-rotation shifting switch,
• said normal-normal-rotation/reverse-rotation shifting switch being capable of switching between
• a normal rotation connecting position where the normal-rotation/reverse-rotation shifting switch is operable to connect said starting switch to said first signal line and to connect said braking switch to said second signal line
• and a reverse rotation connecting position where the normal-rotation/reverse-rotation shifting switch is operable to connect said starting switch to said second signal line and to connect said braking switch to said first signal line,
• said starting switch being configured
• to supply a start signal and a stop signal from said first signal line to said controller, respectively, by turning on and off during said normal-rotation/reverse-rotation shifting switch being positioned in said normal rotation connecting position, and
• to supply the starting signal and the stop signal from said second signal line to said controller, respectively, by turning on and off during said normal-rotation/reverse-rotation shifting switch being positioned in said reverse rotation connecting position, and
• said braking switch being configured,
• in case of the braking switch being a normal-open type switch, to be closed when the tightening completion torque for the tightening operation having been reached and to supply a tightening completion signal to said controller, and
• in case of the braking switch being a normal-close type switch, to be opened when the tightening completion torque for the tightening operation having been reached and to supply a tightening completion signal to said controller.