Carriage bidirectional expansion mechanism and operation method thereof

The invention discloses a carriage bidirectional expansion mechanism which comprises two sets of drawing assemblies, two sets of lifting assemblies and an auxiliary frame, and the drawing assemblies and the lifting assemblies are both integrally installed in the auxiliary frame. Each drawing assembly comprises a drawing motor, the output shaft end of the drawing motor is fixedly connected with a drawing transmission shaft, gears are symmetrically and fixedly installed on the surface of the drawing transmission shaft, a transmission cross beam is slidably installed in the auxiliary frame, a rack is fixedly installed on the bottom surface of the transmission cross beam, and the rack is in transmission connection with the gears. Two sets of drawing motors are arranged on the drawing assembly in the horizontal direction to control two sets of drawing transmission shafts, gears on the surfaces of the drawing transmission shafts are used for driving transmission cross beams, gaps between the transmission cross beam