Patent ID: 9555536
Date: 2017-01-31
CPC Classifications: B25B,B25F

Claim:
1. A two-stage locking electric screwdriver comprises a matching external enclosure, and inside the enclosure there are at least: a motor unit, to provide power source; a clutch unit, coupled with and driven by the motor, the clutch unit has power transmission and speed shifting functions, and can provide two-stage torque output; a screwdriver head unit, driven by the clutch unit, and can be fitted with various screwdriver heads; a trigger unit, to control the starting of the motor of the electric screwdriver, and meanwhile has a function to avoid button reset; and a controller unit, with a built-in micro-controller unit (MCU) panel, and a power source to supply required power; wherein said clutch unit further includes: an internal gear clutch, a lower clutch, a coupling shaft, a torque tube, a torsion spring, and a torque sheath; the internal gear clutch is in the form of a planetary gear, with one side bound with a gear and a gear disc, and coupled with and driven by the spin axis of the motor, and with the other side configured with a pair of interlaced (inner and outer ring) planetary orbits, and with design of cam surface on the planetary orbits formed by interlaced projecting portions; steel balls are provided on the pair of planetary orbits; the cam surfaces of the lower clutch and the internal gear clutch contact each other; the coupling shaft goes through the lower clutch and one of its ends is linked to and moves along with the planetary gear of the internal gear clutch; the other end of the coupling shaft is provided with a torque tube, and the torque tube has a going-through torsion spring, and is further covered by a torque sheath.