Clamping jaw locking device of duct piece lifting appliance and duct piece lifting appliance

The utility model relates to a clamping jaw locking device of a duct piece lifting appliance and the duct piece lifting appliance. The clamping jaw locking device of the duct piece lifting appliance comprises a base body and a guide block, the guide block is arranged on the base body in an up-down moving mode, and an ejector rod is connected to the guide block; the rocker arm is hinged to the base body, and one end close to the guide block is a driving end; the vertical side face of the side, close to the rocker arm, of the guide block forms a rocker arm supporting face, and the driving end is supported on the rocker arm supporting face under the action of a rocker arm reset spring connected with the rocker arm. The other end of the rocker arm is a clamping end and used for being supported on a locking base at the top end of the clamping jaw to prevent the clamping jaw from swinging in the opening direction. The guide block is provided with a lowermost position, a middle position and an uppermost position; a