Electric drill forward and reverse rotation automatic switching apparatus

An electric drill forward and reverse rotation automatic switching apparatus, comprising:

• a gearbox;
• a first-stage gear;
• a first-stage gear shaft;
• a second-stage gear;
• a second-stage gear shaft;
• a transition gear;
• a transition shaft;
• a third-stage gear;
• and
• an output shaft,
• wherein:
• the first-stage gear is fixed on the first-stage gear shaft;
• the first-stage gear is rotatably disposed on the gear box;
• the second-stage gear is fixed on the second-stage gear shaft;
• the second-stage gear shaft is rotatably disposed on the gear box;
• the transition gear is rotatably disposed on the transition shaft;
• the transition shaft is fixed on the gearbox;
• the output shaft is disposed on the gearbox;
• the third-stage gear is sleeved on the output shaft and rotatably disposed on the gearbox;
• the first-stage gear is configured to engage with a gear shaft of a rotor of a motor;
• the first-stage gear shaft engages with the second-stage gear and the transition gear simultaneously;
• the transition gear engages with the third-stage gear;
• the second-stage gear shaft and the output shaft are on a same axis;
• and
• the electric drill forward and reverse rotation automatic switching apparatus further comprises an automatic clutch mechanism disposed between the second-stage gear and the third-stage gear, the automatic clutch mechanism comprising:
• a first clutch convex platform disposed on the second-stage gear;
• a second clutch convex platform disposed on the third-stage gear;
• a clutch block disposed on the output shaft;
• a spring;
• and
• a ball,
• wherein:
• an end part of the output shaft is provided with a center hole;
• the spring and the ball are mounted in the center hole in turn:
• a head part of the second-stage gear shaft contacts with the ball and extends into the center hole;
• and
• the output shaft is axially movable against the spring with respect to the third gear and the gearbox, and the automatic clutch mechanism is configured such that:
• when a force pushes the output shaft to move axially, the spring is in a contracted state to result in the clutch block separated from the second clutch convex platform of the third-stage gear and engaged with the first clutch convex platform of the second-stage gear so that the output shaft rotates in a same direction as the second-stage gear;
• and
• when no force pushes the output shaft to move axially, the spring is in a free state to result in the clutch block separated from the first clutch convex platform of the second-stage gear and engaged with the second clutch convex platform of the third-stage gear so that the output shaft rotates in a same direction as the third-stage gear which is opposite to that of the second-stage gear.