| 主权项 |
1. An electric ratchet wrench comprising:
a body including a first end and a second end, with the first end of the body including an inner periphery having a toothed portion; a ratchet device mounted to the first end of the body, with the ratchet device including a driving member, a pawl device, a first ring gear rotatably mounted around the driving member, a second ring gear rotatably mounted around the driving member, and a direction switching rod received in the driving member, with the pawl device mounted between the first and second ring gears and including two primary pawls, a first secondary gear, and a second secondary gear, with each of the two primary pawls pivotably mounted to the driving member and configured to selectively mesh with the toothed portion of the body, with each of the first and second ring gears rotatable relative to the driving member in a clockwise direction or a counterclockwise direction, with each of the first and second ring gears including an inner toothed portion on an inner periphery thereof and an end toothed portion on an end face thereof, with the end toothed portions of the first and second ring gears facing each other, with the first secondary pawl configured to selectively mesh with the inner toothed portion of the first ring gear, with the second secondary pawl configured to selectively mesh with the inner toothed portion of the second ring gear, with the driving member including an end adapted for directly or indirectly driving a fastener, with the direction switching rod pivotable relative to the driving member between two positions respectively corresponding to a driving direction and a non-driving direction, wherein when the direction switching rod pivots between the two positions, an engagement status between each of the two primary pawls and the toothed portion of the body and an engagement status between the first and second secondary pawls and the first and second ring gears are changed to provide a direction switching function; a power device received in the second end of the body, with the power device including a motor and a power source, with the motor including a motor shaft, with the power source electrically connected to the motor for driving the motor shaft; and a transmission device including a transmission shaft, a spur gear, a first clutch member, a second clutch member, and an elastic element, with the transmission shaft rotatably mounted in the body and including a first transmission portion and a second transmission portion, with the spur gear fixed on the first transmission portion and meshed with the end toothed portions of the first and second ring gears, with the first clutch member coupled with the motor shaft of the motor, with the second clutch member mounted around the second transmission portion and movable along the transmission shaft to selectively couple with or disengage from the first clutch member, and with the elastic element mounted around the second transmission portion of the transmission shaft and biasing the second clutch member to couple with the first clutch member, wherein when the first clutch member couples with the second clutch member and when the motor shaft of the motor drives the transmission shaft and the spur gear to rotate, the spur gear drives the first and second ring gears to respectively rotate in the clockwise direction or the counterclockwise direction relative to the driving member, the two primary pawls and one of the first and second secondary pawls actuate the driving member to rotate to thereby rotate the fastener, and wherein if a resistance larger than a torque outputted by the motor shaft is encountered at a position while driving the fastener and causes a tooth slippage phenomenon in which the second clutch member repeatedly engages with and disengages from the first clutch member, the body can be manually rotated to overcome the resistance and to forcibly drive the fastener through the position at a moment the second clutch member engages with the first clutch member, and the second clutch member reengages with the first clutch member after the fastener passes through the position. |
