A gearbox assembly includes a housing, a cover, a screw rod inserted through the housing along a first direction, a worm wheel integrally formed on the screw rod, and a worm arranged in the housing along a second direction perpendicular to the first direction. The worm is driven into rotation by a driving shaft, so that the worm drives the worm wheel and the screw rod into rotation through a kinetic pair. The screw rod moves a lifting mechanism attached to the screw rod in a vertical direction through screw transmission. A stop pin is arranged on the housing and positioned in the direction of extension of a free end of the driving shaft of the worm against the free end.