Negative-pressure adsorption formation control mechanism and bag opening device using same

The invention discloses a negative-pressure adsorption formation control mechanism and a bag opening device using the same. The negative-pressure adsorption formation control mechanism comprises a movable arm, a cam, a first pulley, a second pulley, an upper sucking disc and a ratchet mechanism. The negative-pressure adsorption formation control mechanism and the bag opening device disclosed by the invention have the beneficial effects that in the lifting process of the movable arm, a ratchet drives the cam to rotate, the cam drives the second pulley to rotate by driving the first pulley, thesecond pulley rotates to drive the upper sucking disc to fall off by a distance adjusting mechanism, a piston rod pushes a piston, the upper sucking disc and a lower sucking disc exhaust, the piston rod retracts the piston to form negative pressure after the cam rotates by a circle, the upper sucking disc and the lower sucking disc adsorb a bag, and the upper sucking disc returns to the original position, so that the open