Impact switching device of an impact drill gearbox

An impact switching device of an impact drill gearbox, including a gearbox front shell (1), an output shaft (2) through the gearbox front shell (1), a torque regulating mechanism (3) on the top of the gearbox front shell (1), an impact mechanism (4) arranged on the output shaft (2), a decelerating mechanism (5) at the bottom of the gearbox front shell (1), and a gear shifting mechanism (6) connected between the torque regulating mechanism (3) and the decelerating mechanism (5), wherein the bottom of the output shaft (2) is connected with the decelerating mechanism (5), the gearbox front shell (1) on its top is prominently mounted with threaded columns (11), and the gear shifting mechanism (6) includes a function switching loop (61) rotationally encasing the gearbox front shell (1), a circular adjustment screw (62) which rotates by the driving of the function switching loop (61), a gear shifting gasket (63) below the adjustment screw (62), and stop posts (64) which slide vertically by the driving of the function switching loop (61), wherein the adjustment screw (62) is grooved with inner threads (621) on its internal surface, through which the adjustment screw (62) is in thread connection to the threaded columns (11), the stop posts (64) are slidingly connected to the gearbox front shell (1) along the vertical direction, the lower ends of the stop posts (64) are connected with the decelerating mechanism (5), the gear shifting gasket (63) is slidingly connected to the gearbox front shell (1) along the vertical direction, the upper end face of the gear shifting gasket (63) is prominently provided with position-limiting bosses (631), and on the bottom of the adjustment screw (62) are prominently and downwards arranged with position-limiting protruded posts (622) corresponding to the position-limiting bosses (631).